How much better are LTs than shorties?

[SpectreG8GT]

I'm looking at header options. If I'm not ever planning on a cam or FI, would shorty headers be plenty acceptable?

MarylandSpeed's website says they picked up 24hp and 24 ft-lbs with just the shorties. Does that sound about right? How much more would I get than that with long tube headers?

Also, do the shorty headers bolt straight up to the stock exhaust?

[GRRRR8]

They would be the only ones that got that gain with no tune. Vector did one and saw 1hp peak and 8hp in a few different spots. If you could get 24, no one would run LTs or LTs are woth 45HP.

[Chewy]

They would be the only ones that got that gain with no tune. Vector did one and saw 1hp peak and 8hp in a few different spots. If you could get 24, no one would run LTs or LTs are woth 45HP.

I think the shorties and perhaps even the stock manifolds with a better catalytic converter setup would yield MUCH better results than shorties with the stock converters. Perhaps that is what they did to show those numbers.

Just my .02¢

[Andy@Livernois]

I'm looking at header options. If I'm not ever planning on a cam or FI, would shorty headers be plenty acceptable?

MarylandSpeed's website says they picked up 24hp and 24 ft-lbs with just the shorties. Does that sound about right? How much more would I get than that with long tube headers?

Also, do the shorty headers bolt straight up to the stock exhaust?

The kooks shorty headers bolt up right in place of the stock header/cat assembly. I would bet the power they saw was from a dead stock car to a car with a tune. usually we see about a 5-10 rwhp gain on shorties, and a 20-25 rwhp gain on long tubes...

[TheTugBoat]

I garantee most of that hp came the tune. And if i remember correctly I think they gutted the cats also.

[SpectreG8GT]

well, guess that solves that problem. Long-tubes it is

[jbradsh1]

Well, just to set the record straight, again, Kirk @ VMS installed my Kooks shorties which came with high flow cats. Now I don't know which gave the rwhp increase, the headers or switching to high flow cats but we saw exactly 15 rwhp on the Mustang dyno with NO other mods, no tune, no nuthin'. So who cares which gave the hp increase, the headers or the cats, but you can say the same thing about LTs, probably some hp comes from the headers and some from the cats. Fact is the LTs make more than shorties, but shorties have other advantages, most of which not many seem to be interested in. There you go!

By the way, when I have the stage 1 cam installed, I'm keeping the exhaust system just as it is. For maybe another 10 - 20 rwhp from LTs, it's just not worth the expense. But if I had it to do all over again I'd go with LT's. They are more expensive but probably worth it, especially if you further modify your car's engine, which I had no idea I was ever going to do. That's life.

[GRRRR8]

How much do ou have in your shortys and cats? I would be willing to bet the price difference wasnt that much and it will only hold the car back when ou try to pump more air from a bigger cam. The only benefit to shortys is if you live in Cali and have strict emission laws. They are not long enough for top end HP gains. You may see a low to mid range gain, but I race at WOT and the big end is where I dont want somebody driving by me.

[jbradsh1]

How much do ou have in your shortys and cats? I would be willing to bet the price difference wasnt that much and it will only hold the car back when ou try to pump more air from a bigger cam. The only benefit to shortys is if you live in Cali and have strict emission laws. They are not long enough for top end HP gains. You may see a low to mid range gain, but I race at WOT and the big end is where I dont want somebody driving by me.

Excellent point. The shorties & cats installed were about $1150 but I've since spent another $600 to install the Magnaflow X pipe and a couple of Magnaflow resonators, so that brings it to $1750 total. I do have 2.5 " pipe from the cats back to the mufflers which opened it up some. So on a stock motor I think I'm set up pretty good (see attached latest 1/4 mile time). But as you point out, when you're upgrading the engine to pump out greater hp that's when the shorties might really let me down, even with the X pipe. But I've gone over this whole issue with Andy and he seems to think, that with my current setup, I shouldn't loose more than 20 rwhp. We'll see. I'm going to have Andy dyno the car as is and then after the cam and head work, then compare that to Paul's car and if the difference is significant, I may still get the Kooks LT headers, but it would have to be a pretty significant gain in rwhp.