Hello everyone, my dad and I purchased an 86 Trans Am as a first car for me to begin driving back towards the end of 2023. As we finally near completing it, I have a little bit of the hot rod bug after reading up on how slow my setup can be. It's a typical LG4 305 with a 700r4 and a 10 bolt 2.73 open diff. It has a few small things done to it such as an emissions delete (smog pump and cat), Edelbrock intake, open element air cleaner, and a double roller timing set. The car will also be receiving a Transgo shift kit and a Corvette servo when it's taken in for a transmission service. We have pretty much brought the car back from the dead and are finally within a couple weeks of it being on the road. My question is, what would be some reasonable mods that I could do to my car to make it quicker? What order should I do things in? Also, things that would likely take more than a weekend would be off the table as I am still in high school and the car will be daily driven.
Any and all suggestions are welcome

 

In regards to mods for that engine, IMO save your money.

Revisit in 5 years, enjoy the car as is now.

 

a posi with a better ratio would probably be the most satsifying. I agree with not modifying the engine until you have the cash/time to build a bigger one

 

I also echo the statements to avoid modifying the 305. However, of your plans are to swap in some other form of Gen I small block you can buy some parts that will transfer over to a different engine (ex. 350) such as exhaust from the headers back to the tailpipe. In the meantime you can also improve the suspension, chassis and brakes as well as fixing anything that is broken. But mostly save your money. You're in HS. At some point you're going to need more reliable transportation as your life broadens and you can't depend on an 80's daily driver to get you to work, interviews, etc. Keep it running, do minor things to scratch the itch but don't go crazy.

 

Build up a mild L31 in the garage and swap it in when it's ready to go. Once you start driving it, you'll probably need to do a lot of very uncool not hotrodding things to make it nice first.

 

 

I have to say it... this question has been answered many, many times on TGO. Maybe a bit of research and reading on TGO will get you on the right track.

It's 2025, very time consuming and expensive trying to restomod a thirdgen. I'm not talking about the frustration of failing parts out of the box and so on. At the end of the day, with your expensive "make it quicker", a Honda Accord Hybrid will smoke you at the red light with only 200hp.

Save your money, enjoy the car for what it is. An antiquated slow sport coupe.

Peace

 

I appreciate the words everyone! I wasn't sure if it would be a waste of money to put any work into the little 305 in it now but the consensus seems to be that it is a waste of money. I most likely will end up doing at least a catback of sorts (probably an SLP Loudmouth) and an eaton posi w/ some better gearing to get a little more out of the car. My main focus for the car is to take the twisties fast aswell so I'll definitely have to spread out where I spend money haha
And I apologize if bringing this up was sort of beating a dead horse, just wanted to see if anyone had any specific suggestions for my circumstances

 

If you like cornering get yourself some Koni yellows. That will be an upgrade worth every penny no matter what direction you end up taking the car in the future.

 

Personally I find a SBC powered vehicle more reliable than most newer cars. The 80s technology will not leave you stranded nearly as often as the newer overly electronic dependant vehicles will. I have driven enough of both with high mileage that I trust an older vehicle better than the electronic nightmares that were built the past 15+ years. Then again look around today and you see every major manufacturers dealership service department inundated with engine failures. GM 5.3L/6.2L, Mopar Hurricane, Ford Ecoboosts, Toyota turbo I6, Honda turbo 4s, to name a few specificially that are failing before their first oil change.

I am daily driving a 1987 at the moment with a spare parts L31 350 in it. I have not had to touch the thing mechanically in a year since I put it together. I freshened up a ~140K mile L31, went through the wiring where it needed work, the fuel system, cooling system, A/C system, brakes, suspension and steering. Still running the GM built TH400 and the factory 8.5 10 bolt in it because they were operating as designed.

I personally would not hesitate at all to pull an old carb era GM out of a farmers field, get it running, do some basic work to it and drive it from one side of the country to the other and back. My brother, a couple of our buddies and I actually did that with a 454 powered P30 motorhome about 10 years ago. Drove it from Texas to Florida, then up to New York before driving back to Texas through Pennsylvania, Ohio, Kentucky and Tennessee. It burned a quart of oil every 80 gallon tank of fuel, threw a smog pump belt at some point and cooked an ignition control module. I have had to do more work on a 4 year old daily driver on a long trip than I did that 1985 P30.

 

HOLY ****!!! Fast and I agree....FAST AND I AGREE!!!! I can't believe it....but Fast and I agree!!! NEW STUFF SUCKS. IDK what any of that has to do with this thread....but we agree for once. Holy Geezum.

OP, Headers exhaust and "free mods" will wake the engine up a lot and should get you into the mid 14's/mid 90's in the 1/4 mile. Put some gear in the back to meaningfully increase the "fun factor" and FEEL of the car; it'll still be "An antiquated slow sport coupe" (in today's world), but it'll darn fun and feel faster than it is...which is 80% of the goal of having a car like this. All transferable to a bigger/better engine, later.

 

The comments about headers are in the right direction. Invest in something decent and it'll carry over to a bigger SBC should you choose to go that way.
The rear gear upgrade is another one that'll move on when the engine is further upgraded.
I'd suggest a converter and if you can find something cheap (say like an S10 converter that the budget guys have luck with) it give a needed boost where you can feel it.

As for 400 and Fast in agreement...

 

I agree also.

 

Steeper gears and posi, headers and full 3in exhaust. Will feel like a different car.

 

I'm gonna go out on a limb here and GUESS that you're like ... 15 yrs old.

Modding a car costs MONEY. And not just in the parts you buy; usually, the gas mileage goes down, the reliability goes down, the maintenance costs go up, and one thing leads to another, all of which empty your wallet.

Leave the drive train alone. When you get a new-to-you car, there is ALWAYS deferred maintenance hanging over its head (all that stuff the previous owner "meant to" do butt "never got a round tuit"), and LOTS of the car's basic systems - tires, brakes, shocks & struts, lights, etc. - have been IGNORED or simply used up while they were intending to sell it.

FIRST THING you should do, is catch up on all that. Tires can make AN ASTOUNDING difference to the way a car drives. Brakes keep NOT ONLY yourself alive, BUTT ALSO everyone else around you; and there are few things worse than buying a car and having them fail. Yes that happened to me... bought a car when I was about 18, less than a week later a brake wheel cylinder popped as I was approaching a traffic light going downhill on a BUSY street; I rear-ended a Pinto at about 30 mph, which since my car (60 Chevy) weighed about 3 times what the Pinto did, launched it into ANOTHER Pinto, and DAMMIT! neither one blew up. Cost me a pretty penny though; I was buying 2 smashed Pintos for the next couple of years, in addition to replacing the headlight that got cracked in my car. (and of course, fixing the brakes) This car you just bought will probably ride terrible; rough, bouncy, wobbly, etc., all of which is the result of the various suspension parts being worn out and ineffective. Various fluids in it probably haven't been changed in DECADES, if EVER.

So, my recommendations would be, in this order:
-

• Brakes - all new pads & shoes, flush all the old fluid out, replace anything you come across in the process that needs it, such as front wheel bearings; lube the bearings if they're still good, replace em otherwise; if there's any sign of rear end grease in the brake drums, it'll need axles & axle bearings, do those when you get around to the fluids
• Lights - headlights, tail lights, brake lights, flashers, hazards, turn signals, side markers
• Tires
• Suspension parts - biggest bang for the buck ANYWHERE on the car is sway bar end links & bushings. Just swap em all out with poly. Rear shocks are EEEEZZZY; do those next.
• Chassis lube - grease em all: 2 ball joints, 4 tie rod ends, 2 idler arm joints, 1 center link joint
• Fluids - oil, transmission fluid, rear end fluid, brake fluid as described, maybe power steering fluid if it looks funky
• Deferred engine maintenance - spark plugs, distributor cap & rotor, plug wires if they're sketch, vacuum lines, broken electrical connectors, etc.

Then AND ONLY THEN begin considering modifications. Along the way of all this, you'll be buying tools, gaining experience, learning about cars in general and this one in particular, etc.; the more of that you get, the better prepared you'll be when you can afford to buy "mods", and the less inclined you'll be to waste your money on shiny things that make the car faster ONLY by way of weight reduction centered on the driver's hip pocket.

 

One of the rare times Sofa and I agree on things too. I would add to that any brake component that has rubber in its construction. Master cylinder, calipers, wheel cylinders and rubber hoses and fully inspect the metal lines for corrosion, replacing any that have corrosion with properly flared tubing. NO compression fittings anywhere in a brake system. The GM lines are bad about rotting where they have those coiled anti crimp springs wrapped around them. The GM product with crossbraking systems were a terrible idea and you do not want to experience losing half the braking system when you need it most. From memory these cars are a cross braking system as built. They stop terribly on 1/2 the braking system. Think Tommy Boy scene where he destroys the model car on that would be customers desk.

Same goes for all the rubber hoses on the car. A blown heater or radiator hose, blown power steering hose or leaking fuel line can quickly ruin your day. Any of those fluids can also easily burn if heated hot enough. Like being sprayed onto a catalytic converter or exhaust manifold that is nearly glowing hot.

 

Diagonal braking system was for FWD cars. RWD cars are front/rear split braking systems. And yes, "They stop terribly on 1/2 the braking system" applies to any car.


I also agree w/SOFA that PM should be the first "mod". Driver MOD should be the second.

 

I was hoping that you would chime in with your opinion sofa. Fortunately we have already done all the maintenance it needs at the moment, the last thing I want is to modify the car before it's in good shape. I'm going to drive it around for a little while to get an idea for the car before I make any decisions, just in case I end up changing my mind or something else comes up that needs to be replaced. Honestly you guys are right though, I should probably just drive the car around and enjoy it for a while and learn it before I want to change it. At the end of the day, Im still a 17 year old with their dream car so it doesn't really matter how the car is, I'm still going to enjoy it and make memories.

 

I completely agree with those advising that you make sure the rest of the car is in tip top shape, and operating properly before getting into the "fun" performance/hot rodding mods. First, it's safer for you of course, and better for the car if it's running properly. You'll learn a LOT. Not only about your car, but how much you're really willing to take on. Not all of us are up for pulling out a motor, and that's ok. Doesn't sound bad on the forums, but in real life, it's not for everyone. Finally, if it's not your daily driver, and you have....the....time.....to relax as you do this work, it can be very rewarding and quite a bit of fun!

That being said, we all like talking about the "fun" stuff. The go fast stuff! My thoughts are with others in that I wouldn't mess around with the 305 too much. Headers and exhaust aren't a bad idea, and at the very least they sound good and look great when you pop the hood. I've also had very good experiences with installing a slightly higher stall converter, along with a finding a better geared rear end with a posi. Both aren't overly expensive. Sounds like the transmission is being serviced soon anyway, and a rear isn't too hard to find used, and isn't really a big project to swap in a weekend. Maybe not the perfect "final" goal, but not a ton of work, and not a ton of money. It'll be a noticeable difference.

 

I know how you feel. I had a 88 firebird pro am in high school with a 305 tbi, 700r4 and 2.73 gears. the single best mod i did was change the rearend to a 3.42. it was an open diff not a posi but still made the car more fun to drive. this can be an easy cheap mod depending on what you find in the salvage yard.

 

the best is swapping in a LS and trans combo..

start with that first and be happy ever after

 

For a novice wrench I disagree especially for something that will be a daily driver. A solid 350 Vortec with a decent cam will tax every component in that car to the point he will want a whole mess of upgrades just to keep up with the 400-430 hp a cammed 350 will make.

 

The seat of pants feel for the buck has to be rear end gears. If you don't intend to road trip it go as high as 4:10 . It will feel like you doubled the HP.