Hey guys I am about to purchase a 1995 Pontiac Trans am with a LT-1 auto.. What I want to know is what it takes to hit 375hp in a Lt-1... LT headers, y pipe, hooker cat back, K&N CAI, LT-4 intake...What other bolt ons are there and what brand headers and y pipe should I use on my beast....Another question is what is the biggest cam I can use while running stock heads with upgraded valvetrain...Now I dont have to worry that much about emissions here in arkansas so its not a factor...any help will be appreciated and my main goal with the car is to hit around 12.8 in the quarter mile

 

In order to hit 375 crank horsepower you are going to need to do all of your bolt-ons (ie. intake/headers/exhaust) and then the addition of a cam. Youll probably actually end up surpassing your 375hp goal, and end up around ~400ish crank if you do it right.

As for brand parts to use, do a search on the boardand youll find plenty of reccomended parts. Same for the cam. You dont want to go too big on stock heads... if you have to pass emmisions or want a good streetable powerband, gas milage etc., most people will reccomend something ranging from the LT4 hotcam to the 224/230. People go bigger all the time though and it really depends on your application, where you want your powerband, how streetable you want your car to be etc.

If all you want to hit is 12.8 though, you dont even need the cam or 375hp. Do your bolt ons, a stall converter, 3.73 gears and a set of slicks. That will put you in the high 12s right there,

 

steve is right a cc 306 or cc 305 will work great!! also you will need to get a tune try MADz28.com, Ion is great to work with. I just order my tune it should be here next week.

 

Glad to see you found your way here, good luck

 

ok I know I am going to use something along the lines of the CC305 cam and valvetrain, Hooker header cat back, Moroso CAI, LT4 intake manifold, I am still unsure about the headers whether to go with LT's or shorties which one makes more power or is it barely noticeable cause lowering the car is going to happen prolly around 2" or so, so long tubes will prolly drag the ground...I noticed BBK makes some shorties with a y pipe...are they good? As for emissions I dont care cause there are no tests here so the cats will be taken off and I want to try and maintain around stock gas mileage if possible...and prolly a decent stall convertor but nothing to radical. and prolly 3.23 gears.

 

Longtubes will make more power but shorties are easier to install, take your pick.

I'd scratch the LT4 intake idea, some ported heads and a CC306 or the infamous 847 cam will make some serious power.

And some 3.73s will do you much better than 3.23s, especially since the auto LT1s came with either 2.73s or 3.23s.

Don't forget tuning.

 

your gas mileage will be better with the engine bolt-ons.
it will go down with a cam, gears, or stalled converter.

 

Don't forget about the right foot.........

 

but all in all I love this LT1 trans am.....they took me for a ride in it and I mean to tell you its a major jump from my 89 350 camaro I am driving now...I cant wait to get her..


I really dont want to have to port the heads but I do want to push them to there max with a CC305 cam which is rather mild for the car but it should maintain pretty decent mileage and still make some good HP

 

Yeah the LT4 intake is not so much for more flow but to match the higher intake ports of the LT4 heads, if you can bolt it to LT1 heads unmodified it would be a large performance reduction due to the port mismatch. There is NO better intake for the LT1 than the LT1 intake, Edelbrock and Lingefelter tried and couldn't come up with anything worth producing.

The tuning is good advice, I see a lot of guys dropping in a cam without it and that is just like putting a cam in an older car and then not rejetting the carb or resetting the timing, just plain wrong and probably cutting the potential gains of the cam in half.

 

Thanks Guys....I appreciate the help...I just got done talking to the place I am buying it from and they said there going to rebuild the tranny before selling it so thats a plus and they said that it had some engine work done to it but I couldnt notice anything like headers or CAI but it did have the exhaust run duals and cut off udner the car..... I took a drive in it on friday and we got on it and it went into 3rd gear roasting the tires so its got some serious potential more so than my friends 95 trans am too but his has a t-56 and he ran a 13.7 in the quarter with just a muffler so I dont know aobut that situation...but I am really impatient to get this car...

 

which header size is better 1 5/8" or 1 3/4"....and been doing some research on the car and I am gonna build it mainly for handling but I still want a mid to high 12 car...

 

Use 1-5/8 unless you go over 383 cubes, this helps your torque with the smaller cubes.

 

350ci is enough for 1-3/4" headers. Don't bother with 1-5/8", you will not see a gain really worth the trouble.

 

man, i'd try to work a deal so when they rebuild the trans they put a higher stall in it, since it's gonna be out anyway.

that will really help put the power to the ground.