Help with 1976 Trans Am

[Trans Am Man]

I just got my dads 1976 trans am with a 455. I want to start replacing parts, and get some more hp. I was wondering where i should start.

[Scrapper]

put you some headers on it and check with eldabrock carb and intake for more power. you could put nitric in it.

[MrPbody]

TransAmMan,

If that is an original 455 car (came from Pontiac with that specific engine in it), I would remove the engine AND transmission, slide them under a bench covered in a moisture "proof" cover and store them for "posterity". '76 455 cars are pretty rare. The '76 455 is a turd as far as performance goes, but the novelty is "special". No matter what you decide, I advise against making any changes that can't be undone. No cutting or drilling on the body, please. This car WILL have collector value in the future, as long as it is relatively unmolested. Anything you remove, label and store for reinstallation, even if you won't be the one.

Once the original engine and trans are safely stored, get a 400 block and get "started". By stroking a 400 to 461, you get "the best of both worlds". That is, the strength of the 400 block (physically stronger than a 455 block) and the displacement/performance of the 455. There are other advantages as well.

TH350 (what's in there now) isn't up to the task of a high-powered Pontiac. Pontiac put them in because TH400 wouldn't fit with the catalyst in place and the "smogger" engines didn't make enough power for them to be a liability. TH400 is the only OEM trans that CAN stand up behind a well-done Pontiac. Torque output far exceeds small blocks, and significantly exceeds big blocks (Chevys).

The 6H heads have HUGE (124 CC) combustion chambers, making them poor candidates for a good performer. If iron heads are in the "future", 6X is a good place to start for the larger engine. Edelbrock, KRE, AllPontiac and Jim Samson all supply aftermarket aluminum heads that are VERY good.

Comp has the cam issue nailed. The XE grinds are superior to any other we've ever tried in "pump gas" engines. Flat tappet hydraulics and solids, hydraulic and solid rollers are all avalable. Flat hydraulics are the "norm" (as wiht most streeters). Flat solids are regaining popularity as valve train parts are more refined. We avoid hydraulic rollers, as the "retro-fit" lifters can be problematic. Solid rollers are the best. Modern parts make them a viable street system.

I would get Jim Hand's book "How to Build Max-performance Pontiac V8s", published by SA Designs, and get "educated" on the current approach to building a strong Injun. 600 HP on 93 octane is straight-forward. It's not "cheap", but neither is any other 600 HP "pump gas" engine. We have guys running deep into the 10s in "drivers" weighing in over 3,500. You don't need to start there, but it IS available, so plan accordingly.

Scrapper,

Adding headers will help, you're correct, but only "real" ones. The three-tube cheapies don't make any more power than the log manifolds. The "HO" or "Ram Air" manifolds make more power than cheap headers. GOOD (Hooker, Mad Dog, Doug's, etc.) headers make a world of difference. CERTAIN Edelbrock intakes will help, too. The factory iron intake on these engines is actually superior to "Performer" for power production and efficiency. At the higher preformance levels, Torker, T-2 and RPM have "their place". Pontiacs don't have nearly as poorly designed factory manifolds as most "OEM" engines. And the Edelbrock carbs are useless on a Pontiac. They're only marginally useful on 350 Chevy, which they're "intended" for. Q-Jet is the best street carb, but must be built by a knowledgeable Q-Jet builder. "Quadra-Flood" and "Quadra-Junk" are statements coming from someone that is NOT a good Q-Jet builder.

For sheer power production, you just can't beat a good Holley. We get ours from AED.

Jim

[455HO4spdTransAm]

1st, but for the 301 which has a diff bore center than the rest any Pontiac V8 engine block is the same as any other and with the corresponding bore size and crankshaft any Pontiac v8 can b made into 326,350,389,400,421,428 or 455. even the 301 has the same outside dimisions, fastner points as well as fastener sizes. Essentually this allows that there truly is no big or small block Pontiac V8.
SOME Pontiac engine blocks are stronger than others due to their nickel content and the type of crank they have, all performance versions of Pontiac V8 engines are hgh nickel and include either a nodular cast crank, or in a few cases such as the race 421, a few of the 1st 428 H.O.'s as well as the famed RamAir V use a steel crank. 421 S.D street, 421 S.D race, 428 H.O. 389 n 400 Ram Air III(the former is tri-power while the latter is single 4v begining in 1967), Ram Air IV 400, Ram Air V 400, HO455, 455 S.D and 455 H.O. are great candidates for building awsome power and tq with the latter 5 being 4blt main blocks.
If u do not have a 455 H.O. in the car, its just a base 455 and has a cast crank vs Nodular iron, but being a 76 it is also as strong as any other Pontiac v8 except the 4blt main versions. Since ALL Pontiac V8 blocks are machined and marked to accept 4blt main caps by simply drilling and tapping the premarked bolt positions and adding the 4blt caps this isn't so much of an issue. Besides, if u don't expect to exceed 650bhp and or 600lb/ft tq even a low nickel content 2blt main Pontiac v8 block will serve just fine, even with a plain cast vs nodular iron or steel crank.
When it comes to building power from any Pontiac engine always remeber they are TQ monsters, as in they thrive on hgh amounts of low rpm tq; therefore hop ups should concentrate on increasing this as well as widening the powerband( that band within its servicable rpm limit where 70 per cent or more of the engines peak tq and or peak hp is created). BOPC(Buick, Oldsmobile, Pontiac, Cadillac) engines respond more to manipulations of duration, cam centerline, and cam seperation numbers than manipulations of lift factors. Lobe center and lobe seperation numbers are best kept between 105 and 110 and split pattern cams where the lift and duration as well as lobe sep numbers for the exhaust are greater than those for the intake. This because like all TQ monster engines they are purposely restricted on the exhaust side of the head so that more heat is contained in the combustion process longer than an engine which might have much better breathing on their exhaust side. This aspect coupled with a Pontiac v8's relatively long rods and stroke which increases the lenth of the pause at TDC and BDC when the piston changes directions accounts for the relatively hgh tq production at low RPM.(the longer the pause at TDC during the combustion cycle the longer the mixture has to burn, thus the leaner and cleaner it burns and the leaner and cleaner any engine burns the more tq it is going to make and the fewer rpm at which it will make same, this is the idea behind long rodding small cube engines, it enhances low end tq production.) Remeber that HP actually only exists in horses. In relation to any internal combustion engine the hp number is simply a mathematical representation of an amount of tq multiplied by the indicated RPM, and it follows that the more tq one produces and the lower rpm at which they do so the fewer rpm one need achieve to produce any desired level of hp factor. This becomes a double edged sword tho, in that if you add too hgh a numerical gear, too hgh a stall speed converter in auto applications or incur a lotta wheel spin, you end up with a fat lazy running engine no matter what you do to it because you unload the engine. With a tq monster when you do that you allow it to rev up thru the rpm range so fast that you incur a situation where you are putting mixture into the engine far faster than you can cleanly burn and exhaust the mixture, thus contaminating all incoming intake charges with unburned hydrocarbons from the previous combustion cycle. Remember that an IC(internal combustion) engine, in addition to being a heat pump, is also a load reader, in that no matter how much power it is capable of producing it is only going to produce that which one can effect enough load on it to NEED to produce, IE; your engine can be CAPABLE of producing 1000hp but if you run out of load at 700 that is all it will actually produce because it has no reason to produce any more. This is where Pontiac and other tq monster engines get the underserved rep of not being able to rev and blowing up when you force them to. ANY ENGINE unloaded at hgh rpm, or even low rpm for that matter, is going to soon come undone, this is why missed shifts and over revving and free revving in neutral leads to quick engine failure and Pontiac engines are no exception to this rule, its just that with their hgh low rpm tq numbers it is far easier to UNLOAD them than many other engine brands. Pontiac engines, given the proper detailed prep, will safly rev as hgh as will any other simularly sized and prepared engine, it is just that it is seldom nessecary to rev them very hgh to create good power numbers and they do not care for a real quick rev up speed for the aforementioned reasons. Save for a done up set of after market aluminums or maybe a set of rare Ram Air V's, once u get to and above 389 cubes with a Pontiac engine the heads are going to b done by 65-6700 rpm with any head that will physically fit the blocks, at which point the engine is going to unload and pushed much past that very often, let go, no matter how well prepped it is, what block or crank you may use.
With Pontiac, unless you plan on a somewhat hgh compression and or Large cube build, stick with the stock intake, other than a weight savings and a pretty look the stock Pontiac 4v hgh perf intake is VERY HARD to top otherwise and ur 76 455 in a TA will have this stock hgh perf 4v intake. With a 455, its a good bet however for performance sake to install a carb adapter and go with a 750cfm Holley dbl pmper for a mild performance upgrade or even stone stock, an 830cfm for a more agressive upgrade, or an 850 for even MORE agreesive upgrade such as HGH comp, BIG camshafts etc... Port or gasket matching of heads on both intake and exhaust sides, as well as the intake(whatever intake you use) up to 1/2" into the ports will do wonders for perf improvement, so much that an all out porting job will yield little more improvement and should be relegated to last effort status after all other avenues of performance upgrade have been exhausted.( never ever polish an intake or head runner, intake manifold and head intake port polishing leads to fuel puddleing and decreased port velocity, while doing the exhaust side of the head is a waste of time and money since carbon deposits will cover same in short order anyway, thisis why extrude honing in porting techniques is so popular, it leave a texture that promotes swirl which increases port velocity, think of an increase in port velocity as a way of introducing a greater amount of mixture into a cylinder in the same amount of space and time cause that is exactly what it does.) If you plan to do a somewhat mild build,or basically STOCK retain the exhaust manifolds but install a 2.5-3" exhaust system that includes a crossover or preferably and x pipe and, whatever size exhaust you run , KEEP THE TAIL PIPES. Headers on BOPC engine short of major upgrades yield far less improvement in perf on Pontiacs than on other brands, since they relieve a lot of back pressure that really enhances the characteristics of the engines nature to produce abundant low end tq. High performance ignition systems on the other hand yield great power gains with Pontiacs as does cold or forced air induction systems. In fact, cut the door out of the back of ur non functional shaker and u can realize as much as a 10-15hp gain with no other changes, better yet just drill it full of small holes. After market oil pans with crawl baffles and extra oil capacity are also a good investment on a pontiac, especuially one making good power and traction, since hard launches tend to expose the pick up in stock pans and starve the engine for oil under the worst of circumstances. always warm a Pontiac engine before driving, especially before driving hard, it does wonders for engine life.
A last tip, there is yet no replacement for displacement, only substitutes that surfice only so long as a larger engine doesn't also employ them. Next, NO ENGINE knows or cares what brand it is, engines of the same size and rates of thermal and volumetric efficiency are going to create the exact same amount of peak power, the only way to exceed this is to enlarge the engine and or raise the inlet pressure above 1psi.
Do not let blind brand loyalty, either your own or someone elses dictate what type of engine you use or how you build it. Try to understand not only how an engine works and what works but more importantly WHY an engine works and its power production characteristics, since unless you understand WHY something works you have little chance of making it work any better than it already does outside of just random shots in the dark, which is seldom very effective. The 2 most important ingrediants in a performance combination are the operator and the chief wrench, the more adept and experienced one is in these 2 areas the less money it will cost one to achieve any desired level of performance with any brand or type of vehicle. MOST IMPORTANT, no matter what you read, or hear about doing upgrades for performance, or anything for that matter, NEVER stop thinking for yourself and reinforceing what you may hear or read with hands on experience. Believe me when i tell you that this is how EVERY advancement in anything was achieved someone read, or heard something, expounded upon it with hand on experience and discovered a way to make something that worked, work better. Never believe that YOU can't achieve the same result since anyone can teach you something, even YOU, even if its no more than what not to do.
You will note i gave no specific numbers for cam specs, engine size, comp ratio etc, this is because these are things best left to the decision of the owner of the ride in question based on his honest assesment of what he expects of the car when completed, honest being the key word.
How do I know all this about Pontiac and tq monsters in General ?
I began buying, wrenching and racing BOPC in 1963, among my Pontiacs have been 5 2cnd gen Trans Ams counting the one i have now which is also a 455, but a 455 H.O., 10 GTO's a 65, a 67, 6 diff 68's including 2 converts, a 69 and a 71; 3 Catalina 2+2's including a 421 street and 2 428 H.O. powered; 3 Grand Prix Model SJ's 1 69 428 4spd, 1 70 455 auto and 1 71 455 4spd, plus Bonnevilles, plain jane catalinas, a grandville, 2 Pontiac safari wagons including a 389 4spd 63 nomad 2dr. On a clean well tuned pass in good air, my present TA will achieve hgh 10 sec ET's @ 127-130mph with a 3.08 gear, full interior, power steering, full exhaust including tail pipes on DOT tires without so much as a set of slapper bars or a roll cage, albeit after replacing the stock super t10 4spd with a TKO600 Tremec SROD 5spd, low 11.0's with a th400 no brake and a 3500rpm converter. Not the best i have known such beasts to run by far but very good for a pmp gas ride that tho it isn't,AND i have a 2 stage wet plate nitrous oxide injection system on the engine totalling 250hp, COULD be a dailey driver and can be driven anywhere i the country at and above the posted speed limit without undue mishap and breakage IMHO(in my humble opinion).