This winter, I would like to put headers(hookers maybe?), a full exhaust system(what would be a good one?), a better intake manifold(edelbrock performer I've been considering), some kind of performance chip(thinking hypertech?), and a 3.23 posi rear, on my auto LG4(completely stock right now) 1987 firebird formula with about 9-10k miles since the motor was rebuilt and with 82xxx on the body. I also have a 180 thermo and hypertech fan switch(on at 200 off at 185) and am doing a full tune up.

How much hp/torque increases would it make(if you could give me estimates at the crank and at the wheels that'd be nice)?

What do you think it would run in the 1/4?

What do you think about my possible choices in parts(I am still researching and haven't decided on anything for sure yet)? If you want, could you recommend some good(but not too expensive) choices?


Eventually I want to switch to a 350, but right now thats not in the cards since I just spent 2000 dollars on this car and only make 150 dollars a week. I want to get this done to it over the winter, then have some fun with it, then next winter swap in a 350.


By the way I did a search and just wanted to get specific answers for my application since I couldn't find one exactly like the way I want mine.

Thanks alot in advance.

 

The Hooker 2055 headers are excellent shorties.

The rest of the exhaust system is up to you, check the exhaust forum for sound clips. Pick what you think sounds the best and has the level of noise you're looking for. At your power level the gains between different mufflers are minimal as far as horsepower is concerned.


I've heard decent reviews about the edelbrock rpm performer, however I have no experience with it myself so I can't really comment.

Your car is carburated, no need for a chip. You can however tune the carburator if you're so inclined. There is a little power left in it from stock. Check the tech articles - they have a good walkthrough.

A posi is a great choice, however I'd go with steeper gears if you're performance minded. 3.73s will retain decent highway mileage. Motive and Richmond both make excellent gear sets in whatever ratio you're looking for. Motives are quieter than Richmonds, however they still whine a little. All aftermarket gear sets will, imo.

I'd expect about 150 at the wheels with some tuning, around 175 at the fly.

If you had some good tires and nice 3.73 gears I'd say a low 15.



See above


And excellent idea

Also might I add, since your motor is almost brand new, consider a cam swap. A ZZ4 take-out cam is very cheap ($100 maybe), combine that with some springs and a weekend to do the work and you could gain an easy 30 or so rwhp and a much sicker idle. It's honestly extremely easy to do by yourself, even for a beginner.

 

My ZZ4 cam'd LG4-based 350 idles as if stock. Of course, it'll be a little more radical in a 305.

 

Yeah it idled like stock in my buddies L98, just sounded alot better. I'd imagine it would sound kinda lumpy in a 305.

 

All those parts will blend decent with each other and should work fine with your 350 uprgrade later

 

Yea, from what I've been reading alot of the same externals can be used on a 350 because the blocks are the same, or it was something to that effect.

I will probably do the cam swap you guys are talking about, I will just need to find a way to get money faster, I have a good hourly rate at my job(for a teenager) but I don't get alot of hours and insurance is a pain in the ***** and so is music equipment...

Thanks for all the advice everyone!

 

Yep, almost every external piece, the intake, and the heads will switch from a 305 to a 350.

 

Assuming the 350 is a roller block.

 

I found something good out today, my motor is not a 305, its a 350, I found the reciept for the rebuilt engine when I was going through the car. I found this out, its a remanufactured 350 cubic inch motor, with the 305 cylinder heads, cam vavle lift in .390 ex .390 lobe 108, valve duration in .240 ex .248 rpm range 600-4600 and a bunch of different parts and things listed(I copied this off the reciept).

It still has the stock exhaust and intake manifolds(from the numbers I got on the intake and the exhaust manifold just doesn't look aftermarket) which I am guessing is holding it back making it not feel as quick as it should be.

Either way I am excited to say the least that I have a good size motor in it. I think I am gonna have to get a second job to get the parts I want quicker :-)