From everything I've read it sounds like LT's would produce more power and torque from 1K to about 4K on almost any LT1. But the question is "HOW MUCH MORE?" Enough more to be worth the extra $300, painful install with trip to the muffler shop for custom Y-pipe (I want to run cats), and decreased ground clearance? I don't know. But myself and everyone else who makes this decision would know the answer if there were only a couple comparison dynos on an LT1 available on the internet. But after a whole lot of looking it doesn't look like there is even one. Am I wrong?
(And if anyone has a reliable number, how much more torque would LTs give over MACs from ~1K-4K on a 94Z with ported heads and 220/226 cam?)

 

Dangit, answer me! If anyone has or knows of such a dyno comparison, you will not only have my thanks but you will also be famous on this web forum.

 

I dont have a dyno for LT's vs my Mac's yet(might be switching to LT's soon)

But i do know that when we dyno, my Mac's produce just as much, actually more than the other cars there with the same mods as me.

If the trade i just saw today happens i could feasibly have dyno #'s soon for you.

 

Im also extremely interested in this. Ive read lots of debates over this subject -- most only give accounts via SOT feeling. Some actually advertise dyno numbers, but not one single time have I seen someone post a before and after dyno chart!

I currently have shorties and iam trying to decide whether i want to move to midlengths, longtubes, or whether its worth it to move up at all.

 

I forget if it was Car Craft or Super Chevy that did a LT vs Mid comparasin on a SBC. It yeilded that LTs produce between 5-8 more hp and 10-15 tq or something along those lines...Basically its not really worth it unless you want miniscule numbers.

 

Thanks, and if and when you get that dyno ford I'd like to see it.

 

That article was a while ago. They actually tested shorties agianst LTs. I was amazed that the shorties made a lot more power and torque down low. If I remember right, as much as 15-20 hp more. They ended up giving up about 10 hp on the top end.

I'm courious to see what mid length headers would do. I seem to remember a member that said he gained nothing when switching from AS&M to LTs. That might be possible with the right set-up, possibly a smaller cam wouldn't benifit as much from LTs as a big cam would. He could of also had a crapy exhaust system.

As I notice your from VA and I know you have to pass emissions. I would try AS&M mid length headers. I have them with a Borla cat back and love it. I installed the whole exhaust at once and the power increase was awsome. I went with mid lengths because I also have to pass emissions and my car will be lowered soon. Cats are a pain to install and ground clearance is at a premium with most LTs. I've had cars with draging headers and it's a drag always worring about if the headers will hit over bumps. I didn't want to go there agian.

 

it is not so much the difference in horsepower with just bolt ons, where i think you see the long tubes significantly outshine them is when a cam and heads come into play.that is just my opinion as iam no expert i just buy everything

 

I know the feeling

 

the motor in the car carft article had a mild cam and only 9:1 compression, a big difference from most of our motors.

My Direct experiences are as follows..

My 93 T/A had a 355 with 11:1 compression, a CC305 cam, home ported heads, 52mm T/B and JBA 1 5/8s headers into no cat and a hooker cat-back (3000 stall 3.73 gears). I ran the car alot in the fall and winter (several years ago in 96 into 97) on some nice cold days I dipped into the 12.6s @ 109 mph. That spring I switched to LT hookers (1 3/4) and a mufflex Y into the same cat-back. I gained an immediate tenth even though it was 40 degrees warmer. That summer I was able to widdle it down to a best of 12.29 @ 113 mph in the same conditions as my best 12.6 was run, but at higher altitude (450 feet so it was kind of a non-factor).

I thought they were worth it. The only thing that I liked better about the shorties is the clearance, and ease of installation.

 

Well for all you newbies or oldies who might not know there is a member here George Baxter who has/had a 97 SS convertable with a Vortech Mondo blown 383 making 763 rwhp with AS&M mid-lengths so NO you don't really need lont tubes to make big rwhp do you!!!!!

This car was featured in GM High Tech back in 98 or 99 I believe, Im sure someone on the board knows for sure.

 

Talk to George about his headers, they were extensively modified, he finally just went to long tubes as well.

 

That may be true but in the article I read the headers were stock AS&M 1 3/4" mid at that time, now I'm not saying he didn't modify them or go to long tubes eventually but you can't deny the rwhp he was making with the stock AS&M mids either.

And how many heads/cam/stroker guys do you think will make anywhere near George's hp levels, not many I bet.

So the point I was trying to make is that long tubes are not absolutely required to make big hp. I think that people will choose which ever one they want but they rely on what they read here on CZ28.com and I wanted those who may not have been on the board at that time to have some additional info in order to may an informed buying decision.

 

if george baxter would have had long tubes he might have hit 800rwhp

 

Just because he made 763 rwhp with mids doesn't mean he can't make more with LTs, you could also use the same argument for a stock cam: so and so runs 12's with a stock cam. That's fast, but a bigger cam would almost definately be faster. I'm sure with georges setup, he could make big hp on stock manifolds, so that argument doesn't really hold water. . I went from jba's to jethot LT's and gain 2 mph in similar weather, my 60' was off, so the et's were the same, but it was worth it to me.