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Thread: 3.4 Modification Encyclopedia

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    Aug 2008
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    3.4 Modification Encyclopedia

    This Encyclopedia will not be alphabetically formatted or even layed out by difficulty of modification. Instead, consider it a in depth look at the functions of the 3.4 motor from beginning to end and it's upgrade choices along the way. It will be continually updated with new mods/info as time allows.


    There are three basic principles to making power in an engine. They are air, spark, and fuel

    The air consists of all your intake and exhaust components (how quickly can you get the cool air in and the hot exhaust gasses out). The spark consists of your spark plugs, wires, ignition timing, and coil packs. While your fuel consists of the amount of fuel, fuel pressure, and fuel maps. All three upgraded in conjunction will give maximum results and often must be done together. For instance, adding a lot more air will require more fuel to keep the A/F ratio in tact. This can become difficult on the 3.4 motor because of it's lack of tuning but there are ways to combat that. Besides those three components there are more ways to improve the 3.4 including suspension upgrades, as well as tuning, and upgrading the drivetrain. For now we will stick to the main three components, the first of which is Air and the modifications available to get it into your motor faster and get the exhaust gasses out quickly. Upgrading the air intake while neglecting the exhaust will simply create a bottle neck so it's important to do the whole Air system and not just pieces of it.

    Air Intake

    Generally speaking the more air you can get into your engine the more power that is made and the more economical your gas mileage becomes (slightly). This being said, most stock intakes are barely adequate for more than a slight trickle of air to enter the engine. Most manufacturers take audible noise into consideration and try to keep the sound of air rushing into your engine at a minimal level. While this is great for a luxury car, it has no place in the F-Body platform.

    Three things are to be considered when taking into account the effectiveness of an intake. Direction, Size, and Filter. The stock 3.4 intake is horrible in each of these categories. The rubber elbow connecting to the throttle body is asked to make a 90* turn, horrible for air flow. The straighter the path, the more air can enter. Secondly, the stock intake is pathetically sized, at least internally. When taking a closer look inside the intake one can see that the smallest bottle neck consists of a few mere inches from which air is expected to fit. Finally, the filter. If it's a paper filter, it's crap. Paper filters let little air flow through as it is. Add that to the diminutive diamater of the stock intake and it's counterproductive 90* turn and you can start to see why adding a new intake is the first step into waking up the 3.4 motor.

    So what are the options?

    A cold air intake is a good place to start. It means just that. You are literally ripping out your old stock intake, which gulps hot air from the engine compartment and replacing it with an intake that sits down underneath the engine compartment, suckin in cold air and more of it, which helps to make more power.

    There are many Cold Air intakes out there, and they more or less do the same thing. Open up the airways with wider piping, relocate to a colder air source, and usually include a high performance air filter. As a rule, the only filter we recommend is the K&N filter. It is the best filter in the business. (Consequently you could just change your stock filter to a K&N and see minimal results but after discussing the 3.4's shortcomings, not upgrading the whole unit seems pointless)

    A K&N stock replacement filter will usually run you 45$. Part # KNN-33-2042

    Continuing on with the Cold Air intake options for the 3.4 there are a few popular ways to go. First is the Ebay kits. I am including them because some of them really aren't that bad. Just make sure they come with a k&n filter. These kits can be hit or miss in terms of ease of installation but they are certainly an option. Usually an Ebay kit with K&N filter will run you 85$

    Ebay kit shown here:

    There are 2 other options left, and they are both superior to what we have discussed thus far. The first is to go with a quality cold air intake kit, such as a moroso or K&N FIPK (fuel injected performance kit) They are both well manufactured and put together, however the K&N FIPK seems to be the most popular. They will all run you 200$ + but you get what you pay for.

    These are easily your best bet at a cold air intake. They will improve throttle response significantly, as well as increasing gas mileage slightly and also giving an audible sucking noise when accelerating.

    K&N FIPK part # KNN-57-3010-1
    Moroso part # MOR-65840

    K&N FIPK shown here:

    The final option I will touch on briefly is switching to a Ram Air kit. Ram air kits, are the BEST way to get air into your motor as far as the 3.4 is concerned. However it's not the most convenient method since one will have to first switch the stock hood to a Ws6 hood with functional ram air scoops, as well as modifying the intake elbow to attach the ram air kit. Many v8 Ws6 Trans am's had these intakes that you can find on ebay, as well as a kit that is sold by suncoast creations. They are NOT cheap, usually one will cost 250$ + but it is the most helpful intake out there for the 3.4, especially since it eliminates the 90* turn, making it a nice straight shot into the throttle body.

    Picture of a Ram Air Kit on a 3.4: * note, the ws6 hood and subsequent ram air intake is only available for the firebird.

    the Suncoast Ram Air Kit part # is 28001K

    When it comes down to it, replacing the stock intake on the 3.4 is easily the best place to start when it comes to modifying this engine. There are many different ways to do it, and many companys that make intake kits. It should also be noted that the cheapest method would be to simply make your own kit. Materials could easily be picked up at any Home Depot, such as metal tubing, hose clamps, etc. however if aesthetics are in consideration i would suggest sticking to a prebuilt kit.

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    Throttle Body

    Continuing on our journey with the 3.4 modifications, we come to the throttle body. The air intake connects to a rubber elbow that subsequently attaches to the throttle body. This is undoubtedly one of biggest restrictions on the 3.4 motor, spanning a pathetic 50mm and unfortunately one of the most difficult to improve upon. Many ask "Can I buy an aftermarket throttle body or swap a bigger one from another vehicle?" The answer is NO. There are limited things to be done for the throttle body, two to be exact, and they both involve time and modification.

    The first and more easy of the two options is to remove and have the stock throttle body ported and polished. This can be done with dremel tools and a good portion of time. Porting and polishing the stock throttle body will open up the port a bit, smoothen out the surface for air to move along, and help out a good deal. This modification nets arguable gains in hp and throttle response, but every little bit helps on the 3.4.

    You can do this mod yourself, or if you don't feel crafty with a dremel there are those out there who will do this for you. Expect to pay ~ 80$ for this to be done.

    Pics of stock throttle body vs. P&P throttle body.

    The second, and more difficult option for the 3.4 throttle body involves mating an LT1 Throttle body onto the 3.4 plenum (upper intake) The Lt1 throttle body is a twin butterfly design with two 48mm ports. This will involve machining the 3.4 plenum to allow the use of the bigger throttle body, so it's not for your every day 3.4 owner. However, those who want to maximize the 3.4's potential, this is the BEST option available.

    Picture of LT1 Tb on 3.4 plenum

    these are the only feasible options for upgrading the stock throttle body on the 3.4 motor, however it is one of the essential upgrades necessary to make these cars go. Your air intake is only as good as the smallest bottle neck and this may be it.

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    Upper & Lower Intakes

    The next step into the 3.4 motor is the Upper (Plenum) and Lower intakes. As air passes through the throttle body via the air intake it enters the upper and lower intakes. These intakes are stacked one on top of another with a gasket sandwitched in between. Air enters the upper intake, splits into a Y, and then continues down each runner into the lower intake manifold where fuel is added by the overhead fuel injectors as it begins to enter the cylinder heads for combustion.

    3.4 Intakes shown here:

    The 3.4 intakes are poorly designed. The upper intake has little volume internally and the lower intake runners are thin and short, making the 3.4 run out of breath quickly during acceleration. Many have noted that their 3.4's seem to run out of breath at around 4,000 rpms, the poor design of the intakes is certainly to blame.

    Cutout cross section of the upper intake shown here:

    The intakes aren't the only reason the 3.4 runs out of breath quickly, lots of it has to do with the iron heads that come stock on our cars (more on that later) but it's a necessary part to modify if you want to get the most out of your engine. Many ask "Is there any intakes I can swap from another engine without changing the heads?" The answer, like the throttle body is NO. Well, not exactly. It is possible to swap over an intake from a 3rd gen. 2.8/3.1 camaro or firebird but it's not an upgrade. I've also heard the fiero v6 intakes can swap as well, but once again not an upgrade. Their are only two feasible options for opening up the intakes on the 3.4. The first is to port, polish, and gasket match the stock intakes as best as possible, and the second is to undertake the 3x00 swap (a lot more on that later). But for now, we'll stick with the stock pieces.

    There's not much that can be done on the upper intake, at least internally, however it is possible to do some work on the throttle body opening, as well as porting out and polishing up the intake runners on the bottom of the upper intake. This can be done with a dremel and some good bits, as well as a good amount of time.

    Worked intake shown here:

    It should also be noted that some have chopped off the top half of the upper intake and machined on a bigger top, however doing so will not allow the upper intake to fit into the f-body engine bay since there is only about 2 inches of clearance to begin with from intake to the edge of the metal cowl. Only transplanted 3.4's really have this as an option.

    The lower intake by comparison can be ported out quite nicely. The runners are easy to reach with tools, and it can also be gasket matched like the upper intake.

    Lower Intake shown here:

    Considering the poor design of the 3.4 upper and lower intakes, it is essential to not leave them out of the equation when trying to improve one of the biggest restrictions on this motor.

    Expect to pay anywhere from 150-250 $ to have these ported, depending on whom you go to. Of course, porting it yourself is always free.

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    Cylinder Heads

    As the air rushes down the intake runners towards the heads it is mixed with fuel from the overhead injectors and split just before the intake valve by the port divider. Head flow is key to performance since it is the last venue prior to the combustion chamber. Unfortunately the heads on the 3.4 are near as poor as can be in regards to flow, volumetric efficiency, and even weight.

    What is the reason for this? GM upgraded the v6 camaro/firebird application 3 times from 1982-1993 starting with the newly fuel injected 2.8 in 1985 (135 hp, 173 cid), followed by the 3.1 in 1990 (140 hp, 191 cid) and finally the 160hp, 207 cid 3.4 liter in 1993 as the fourth generation began. All three of these motors are from the same 60* family. While their cid, accessories and other parts may be slightly different they are in fact very similar to one another. In fact, it is true that many engine upgrades that can be done on a 3.4 can also be done directly on a 2.8 or 3.1 60* motor. Somehow through all these years the cylinder heads stayed pretty much the same and found their way onto the new 1993 camaro/firebird. These 32 lb cast iron "boat anchors" have been compared to a set of v8 heads with a pair of cylinders "hacked off". The only thing that is truly hacked by these heads is performance. A stock cylinder head usually flows 129/120 cfm @.500 at its best. This is sad when you look at the significantly lighter 3100 aluminum heads which flow ~ 162/139 cfm @.500 It is for this reason that many are upgrading to the better performing aluminum heads off of 3100's, 3400's, and 3500's (aka the 3x00 swap) There will be a lot more on the 3x00 swap later, but for now we will stick with the stock heads.

    These heads came from GM with significant casting flaws aside from their poor design.

    Stock cylinder head:

    Stock intake runner (port divider shown)

    So what can be done to improve the heads on the 3.4? If you choose not to undertake the 3x00 swap (which includes swapping intakes and other modifications) than the only one left is to work on the existing stock heads. Because of the poor design and casting flaws there is some good improvement to be made on these heads. The intake and exhaust ports can be gasket matched and polished out to remove casting flaws and impediments to air flow. Bowl work can be done as well as "shark finning" the intake port divider. It is a bad idea to fully remove the port divider since it serves an explicit purpose in splitting the air before the valve and will actually hurt air flow. Depending on your performance aspirations you can have the valves worked to a certain degree. Unfortunately you cannot really affect the poor design of these heads but porting, polishing, and gasket matching will improve these heads significantly. The best iron ported heads have seen flow numbers of ~ 158/142 cfm @ .500 (just shy of stock 3100 heads) Because of this, there is a definitive roof for performance that cannot be surpassed. Anyone wanting more power will have to swap to the aluminum heads which have more potential.

    Worked intake port:

    Worked exhaust port:

    The final product:

    As you can see, there is much to be done for the 3.4 cylinder heads. A good machine shop can usually do all of this, though prices will vary depending on what is done and whom you go to. I would not suggest attempting something of this nature unless you have prior experience. This particular set of cylinder heads (shown above) were done by John Caraher owner of whom you can contact if interested in head work or the 3x00 swap for that matter.

    This concludes the first part of air intake modification into the 3.4 60* motor. We have discussed the actual pieces that allow air to enter the motor (Air intake, throttle body, upper & lower intakes, and cylinder heads) Upgrading these simultaneously will net the biggest power gains, but they are ususally done one at a time. The second part consists of valve lift and it's components.

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    Rocker Arms

    The second way to increase air flow into the engine is to increase valve lift. There are two engine components that affect lift. They are the camshaft and rocker arms. Rocker arms are more straight forward than cams, and usually don't require upgrading anything else in the process, whereas a camshaft will often require upgrading the valvetrain components and timing chain. This being said, rocker arms are the easiest way to increase lift without digging too far into your 3.4 motor.

    Comp Roller Rocker Arms on the 3.4

    The rocker arms are located just beneath the valve covers. Unfortunately upgrading the rocker arms on the 3.4 can be difficult for three reasons. First, the aftermarket for rocker arms is not vast for the 3.4 . The stock rocker arm ratio is 1.5 and the highest ratio ever seen in an aftermarket rocker arm is 1.6. Secondly, unlike your daddy's 71 mach1 you can't just remove the valve covers in a matter of seconds. The 3.4 requires the removal of the upper intake plenum and all it's wires/hoses as well as the removal of the EGR to take the valve covers off. When you consider the depth of a cam install its really not that bad, in fact it's rather simple. The third reason for difficulty is that the rocker arms on the 3.4 are not "self adjusting", valve lash will need to be set after installing new rocker arms, and it can be a real pain some times trying to figure out how to do it. Picking up a haynes or chiltons manual will help clear this procedure up.

    The ratio of the rocker arm correlates to the amount of valve lift. A higher ratio equates to more lift, and thus more power. Besides the ratio, there is another aspect to aftermarket rocker arms that help power. Roller capablilty is said to free up some power by reducing the friction of the rocker arms movement on the valve stem. This is more of an added bonus to a rocker arm as the real power is made in the ratio and correlation to valve lift. Comp Cams makes two sets of rocker arms, both roller action. The 1.52 ratio rocker arm is a very slight upgrade over the stamped 1.5 ratio rockers. They are moreso for people who want to replace old worn out parts rather than feel the benefits of a higher ratio. To be honest, it doesn't make much sense buying these as they cost nearly as much as the 1.6's. The second as previously mentioned is Comp's 1.6 Roller Rockers which are superior to the 1.52's. So what kind of power gains are to be had? Like all modifications you will not get the true benefit out of these rockers until you upgrade the other parts around it. One testament stated the 1.6 RR as boosting power by about ~ 8hp (at the crank) on they dyno. Also, it is a good idea to upgrade to Comp hardened pushrods at the time of a rocker arm install, though its not mandatory.

    Be sure when purchasing rocker arms that they are for the use on 10mm rocker studs, as this is what comes on the 3.4 heads.

    Comp Roller Rocker:

    Comp Cams 1.52 Roller Rocker part #1413-12 ~ 116$

    Comp Cams 1.6 Roller Rocker part # 1414-12 ~ 125$

    *note- Crane does make a FULL roller rocker that is very pricey and would necessitate changing the rocker arm studs to 3/8.

    Comp Cams Hardened Pushrods (stock length) part # 7816-12 ~ 30$

    Go Back to the Top


    Upgrading the Camshaft is the most productive way of increasing valve lift. Cams are in essence not particularly easy to comprehend, being that there are many variables that go into a cam and therefore the selection process must be well thought out. There are some cams meant for boosted applications, others for cars looking to be very street-able, while some offer radical changes that will make street-ability quite out of the question. The first question you must ask yourself when choosing a cam is what are your power goals for your 3.4? Some cams on the market are even smaller than stock, or very close to, therefore it is necessary to understand what the specs of a cam mean. For starters, take a look at our Cam FAQ page HERE, that will get you familiarized with the basic compounds.

    The #'s for the stock 3.4 cam are 195/201 .390"/.410" 109

    Thats: Intake/Exhaust Duration @ .050" lift | Intake/Exhaust Valve Lift with Stock Rocker | Lobe Separation Degree

    Click HERE to view our list of 3.4 camshaft options.

    Upgrading the rocker arm lift from 1.5 will affect the "overall" lift. The combination of cam lift and rocker arm lift will give you your total lift, but keep in mind too much lift will put you in danger of valve float and will require the upgrade to heavier valve springs, which consequently will necessitate upgrading the stock timing chain to at least a double roller chain which is much stronger.

    As a rule, it is necessary to install new lifters when installing a new camshaft. Companies like Comp sell cam packages that include everything necessary for your cam install. A full cam kit will generally include cam, lifters, valve springs, valve spring retainers, valve locks, valve seals, timing chain, and cam lube for installation purposes. Many of the items are upgrades over stock such as the heavier springs, double roller timing chain, and hardened lifters. It is important to match the proper valve springs with the new cam, as well as other components. Therefore it is highly recommended to go with a full kit, as opposed to buying them one piece at a time.

    Comp Cams "Full" Kit 16-233-4

    So what other items will be necessary for your cam install?

    For cam install, you will need a good cam lube as well as either 4 quarts diesel oil to run with your cam break-in or a bottle of cam break in oil additive to be added to conventional oil (do not use synthetic oil for break-in)

    Comp Cam Lube & Cam Break-in Oil Additive:

    Also, engine assembly lube is reccomended for the journals of the cam, while the cam lube is reccomended for use on each lobe. It never hurts to pick up both. Engine assembly lube can be found at any local auto parts store.

    Besides the lubrication of the camshaft, it is important that if new lifters are to be used, that they be soaked in oil for at least 24 hrs. before installation. This will help "plump" them up for initial break-in.

    Besides all of the above listed parts, it may become expedient to purchase other things prior to your cam install, such as gaskets, RTV, new water pump, sensors etc. though this will vary on an individual basis what else is needed.

    Besides these basic concepts and items, there is some more particular information regarding a cam install on the 3.4 worth noting. The 3.4 motor, unlike it's 2.8 and 3.1 predecessors employs the use of a camshaft sensor which is fitted into a chasm just in front of the LIM base on the block. This sensor reads a magnetic tab on the first cam journal to monitor revolutions and compute this information to the ignition system. This is important to note since many cams available for the 3.4 do NOT have this magnetic tab for the sensor to recognize. Fear not however, as this will simply revert the computer back to "batch fire" injection which at the most will lose you a few mpg. It is important to note however for those hoping to keep their SFI system in full perfect harmony.

    Also, the 3.4 uses an oil gear drive that is meshed up with the camshaft at it's rear most journal. This gear drive is fit down into where the distributor hole would be on older vehicles. There is black rubber O ring that is notorious for hardening over time and leaking oil around its base. Replacing this O ring is an absolute certainty in the least, however there is a teflon O ring that is now available to replace the older rings succeptible to hardening and leaking over time. It would be wise to pick this up at the expense of a few dollars more.

    A cam install on a 3.4 can be done with the engine in the car. There is adequate room to do so, though it is suggested that the radiator be removed first. It is however, impossible to replace cam bearings with the block in the car, therefore if they are to be replaced or any other bottom end work to be done, it will necessitate the removal of the engine.

    Be prepared to dig deep into your 3.4

    Finally, the cam "break-in" procedure is one that must be done properly to ensure that the new engine parts are not damaged. Generally with flat tappet cams, such as in the 3.4 it is suggested to run the engine in a stationary position for 20-25 minutes at about 2,000 rpm. Some variance is allowed within that time, however dropping anywhere close to or below 1,500 rpm is not acceptable. Some companies will suggest other break-in procedures for their cams so it is important to check with the manufacturer first before performing the procedure. Once broken in, the oil and filter must be changed immediately, with another oil/filter change 500 miles after. The use of a good quality oil filter is essential for cam break-in, something like a K&N Gold Class filter will fit the bill.

    Keep in mind, adding a big enough camshaft will necessitate upgrading the fuel system. This can be done by swapping in bigger fuel injectors, or simply upping the fuel pressure with a fuel pressure regulator (more on those later)

    -The price for seperate cams, custom grinds, and cam kits are too numerous to list and will vary between manufacturers. Our own sponsor at offers cam kits for the 3.4, and is a good place to get acquainted with the available products.

    - Comp Cam Lube- Part #

    -Comp Cam Break-in Oil Additive-Part #

    K&N Gold Class Oil Filter- Part # hp1001, or hp2001 (same price as 1001, only twice as much filter area)-

    Teflon Oil Gear Drive O Ring- Part#

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    Last edited by tkoforpresident; 06-27-2009 at 11:47 PM.

    93 3.4 Firebird
    Pacesetter Headers, Flowmaster 80, Comp 1.6 RR, Custom Cam, Cloyes 2x Set, P&P Heads & Intakes, Ram Air Intake, Posi Rear w/3.42's and Disk Brakes, OBD-1 Swap.
    Cam and Heads by Tune By

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