I recently bought a 1988 trans am GTA, and I'm trying to figure out what I'd like to do with it. I'm new to building cars and fairly inexperienced, but I would like to learn on this car as much as I can. So far, I think my goal is to get to 400 crank horses, or fairly close. I've been looking at the bottlenecks of the 350 and the car and know that I need to upgrade the heads and intake manifold. My goal is to keep it TPI, as well as try to stay revving close to stock to prolong the engine life and require fewer engine internals to be built (Also I love the low-end torque lol). Does anyone have advice or combos of what heads and intake manifolds I can match that allow me to stay with the TPI? A lot of companies have stopped making some of their old manifolds, which makes a lot of the forums I'm reading fairly outdated. I would also like, if at all possible, to stay under the stock hood and not need to cut out a hood scoop. Any advice would be appreciated while I navigate through the build.

 

The goal of 400hp and tpi is a little counter intuitive. At least with 350ci. Not impossible, just more difficult. HP comes from revving. Tpi doesn't rev. Which means to work with long runners, then the cam can only be so radical, which is also counter intuitive to more hp. More ci or shorter runner intake makes it a lot easier.
My suggestion for your goal, FIRST manifold, any 195cc aluminum head, something like trick flow or afr enforcers and a 220 ish intake duration cam. (Talk to cam vendors like Comp, Lloyd Elliot, Jones, to make an informed choice). Support it with good exhaust, etc etc etc and you'll be around your goal. Then how are you going to tune it? Next is your axle ratio, brakes, and chassis support.
I switched to an hsr and miss none of the torque but enjoy the rev to 5500, even with 3.08 gearing. Just something to think about. Good luck on your journey

 

If you want to make 400 net HP at the crankshaft with the engine installed in the car with a stock appearing individual long tube runner TPI induction system you are going to need a stroker motor.

 

i have always been told that fuel-injected is a more efficient system than carbureted, but i know a lot of 3rd gen enthusiasts love converting to carbureted. If wanting to stay electronically tuned, would tbi be a better system to get power out of? i assume the reason tpi is harder to get power out of is due to longer runs when having to fit in the injectors. From the research i have already done I'm pretty heavily leaning towards 195 heads, and will probably go with afr enforcers as they dont seem to be overkill (at least not overly) and are also high quality, so i was trying to see if any tpi manifolds would complement them and be able to push 400hp to the crankshaft with ~36lb injectors and a cam. There is a flipping point for me where i could move to a different system if tpi really is to hard to push power out, to the point it outweighs the desire to stay with the car's original system.

 

there inlies the rub. Every change of any sort is going to have a drawback. Converting to carb can work great but can you tune a carb? Luckily needs fewer tools to tune but no less knowledge. Which carb? There's more than one reason factories stopped using carbs 35 years ago. Switching efi systems all have some draw. Factory stuff from then is antiquated and much harder to tune these days. Newer factory stuff (think lsx computer) all has to be integrated and works great but it's likely *you're* making the harness and possibly self tuning. Aftermarket systems often have nice harnesses and often self tuning but then you're relying on aftermarket quality control on things like throttle bodies, ecms, sensors. OEM definitely has better reliability in those cases. And at the end of the day, how much of this can YOU take on? Many shops don't want to touch this work. Others aren't cheap. Just more food to think on.

 

I unfortunately don't come from a family with any mechanics or really anyone with much knowledge on cars, so learning is harder than it may be for some. i think i would be able to do most of the mechanical mods myself, other than building the transmission, but i do not think I'm confident in tuning if i were to go to a standalone ecu that would be possible to tune at home. i dont know if any of the tuner shops around here even still do old cars, so ill have to call around before i start fully into the project. though i am willing to put a good amount of money into the car i am not trying to build a drag monster; however my horsepower goal may be to ambitious with the level of experience (or lack thereof) that i currently have. i likely won't be starting the power push till late next year, or even possibly 2027, as restoring the car cosmetically to its former glory is the first goal. This gives me a lot of time to work on a plan to reach a set goal, and some time to learn what I'm even doing. As i said though, possibly i am aiming to high as my plan was to build this car enough to gain some experience, then likely sell it (years down the road, im not looking to move on to quick lol) for a Corvette which i can really push power out of.

 

this isn't an attack on your skills or ability to learn mechanical skills, but honestly if you want to go faster, these days it's just easier and smarter to buy a faster car. Newer stuff or even older stuff is easier to build and tune if you want to become a wrench and tinker on your ride. 3rd gens are really in a weird spot in this day. If it works fine, drive it. Enjoy the 3rd gen for what it is. Nothing wrong with that. My 77 certainly isn't fast. Other than exhaust and tuning, its stock, maintained and very fun to drive.

 

I totally get that and honestly, as much as i love the look of the car, I'd be more likely to get something newer with a bit more power, but i was sold the car (pretty much gifted the car given how much i paid) by a close family friend. it was always his dream car growing up and after he bought it the radiator went bad and he didn't have the time or money to fix replace it and the car just sat. he recently decided hed never get the time to fix it up at this point, so he sold me it under the condition i drive his son to prom in it when hes older, so im gonna have it for at least 7 more years. i asked if he would rather i keep it stock or not, since I'd prefer to get a bit more power out of it, and he said he'd love to see it with more modern numbers. Personally, i think that older cars should be left original on the outside because that's what makes them iconic, but there's no reason you shouldn't be able to change the engine bay. i still want to keep the 350 however. i realize how unfortunately weird of a stage Firebirds and Camaros were in at that stage though, but it's what I've got for the foreseeable future (which im pretty ok with, i love how it looks lol).

 

If you ultimate plan is to sell it, depending on what condition it is in and miles on it, I'd pay more for a completely stock car, or at least mods that are from that era than I would for one that has been modified. But thats just me. Some porting and a different cam wouldn't bother me but I'd be buying it for the joy of having a car from that era. at a minimum, save the parts.