so how much actually torque and power am i going to gain with long tubes, over shortys,, i have shortys sitting right here next to me,, opposed to long tubes im ready to buy! is it really that worth it? or am i just pissing in the wind.

 

Ive been told that unless your planning to mod you ride with >500hp than no significant HP measurement is observed. I have gone with the shorties and are truely pleased with the results. Most people will testify to go LTs and that is fine. I personally have to deal with low clearance where I drive, thus further biasing me to go shorties. On how much actual torque and HP gains between the both can be tricky. I think the shorties on your 1987 IROC 305 would make a significant impact. By the way, anyother exhaust or induction mods you have???

 

LT's really are the way to go - a good set, with proper fitment, will give
you close to stock clearance. My LT's tuck up pretty much as stock.

 

Pontiac_97, the original poster has a 1987 305.

 

If this is for your 87 with the 305 in your sig., then i would make sure you stay with a smaller primary tube, the tube size has great affects on torgue too, so does the collector size & length of the primaries & collectors, those 305s lack torgue, so be careful what you throw on there for headers, i had a 305 in a full size 2wd blazer, i put a set of 1.5/8 headers on it (i was worned), it was a TOTAL pig , but i solved the problem later on, dropped in a 72 400 SB "Yeah Baby", that sucker COOKED So choose wizely, if it were me, i would see if they offer a header in a 1.1/2 primary full length for your car.

 

By the way, anyother exhaust or induction mods you have???


flowmaster cat back, and no cat,,, im going with true duals in 2.5 pipe with 2 dynomax racebullets

 

My 1991 Auto Lb9 (5.0 Tpi) put down 270wtq bone stock. Pretty sure my brothers bone stock auto LT1 put down 267wtq. Not bad for something with 45 less cubic inches and I would hardly say that it lacked torque.

After I installed shorty pacesetters on my car, I didn't really notice much of a difference other than sound. Top end felt a little better though. If I could do it all over again, it would've been long tubes. But the install of the shorties was a breeze. 2 hours max.

 

WELL ive got the shorties here,, so im just gonna go with them,, i got em free back 4years ago as a tip on a job( pretty good tip huh) customer of mine sold his old iroc,, anyway thats what im going with nothing better then free ya know

 

longtubes have much better plug access. don't have to drop the y-pipe for plugs, changing starter, etc

 

No significant peak horsepower measurement is observed.

However, longtubes have a significant advantage over shorties in the low RPM range.

 

I find this hard to believe, i had a 90 Z28 with a 305, it was a total DOG period compared to a 94 LT1 Z i had & now this 97 LT1, cubic inch is cubic inch., if you have an earlier Z28 with a 305 with the same mods i have, i'll be glad to line-em up, then will see which engine has more torque, & you did say i'm "pretty sure", so thats not stating facts to me, i may be new to these F body cars, but i'm not new to engines.

 

I'm sorry, I didn't know we are now comparing horsepower. I thought we were comparing torque. Maybe your 90Z28 was a Pos? My 91 Was a good running stock car. So maybe it's just the owner not caring.

 

I myself agree that its possible for a healthy peanut cammed 305 tpi to make a little more "peak" torque than a typical lt1. But the 305 will fall on it face by about 4,000 rpms. The lt1 may not peak quite as high as the tpi motor... but it will definitely hold a strong, steady torque curve from idle almost all the way to the redline. This will result in the lt1 car being much faster. So one car makes 267 and the other makes 270 at peak on the dyno. That doesn't mean the car with 270 lb feet of torque is a faster car. It's the average torque throughout the rev range that makes the car faster.