Right now I have the SLP 1 3/4" shorties and the flanges block at least 1/8" off the top of every exaust port. I'm looking at possibly getting the hedman 1 5/8" longtubes (68469). Now I know that the 1 3/4" primary tube size is better than the 1 5/8" primary tube size and that longtubes flow better than shorties. What I don't know is wether it's worth switching from the 1 3/4" shorties to the 1 5/8" longtubes. I've read the stickies and searched but I haven't really found a definitive answer as to wether it's better to have the larger primary size or the scavenging effect of longtubes. I'm leaning toward the Hedmans because of the blockage on the SLPs and because they're almost impossible to keep sealed. I'm not totally sure what to do and was wondering what you guys think, or if you know of any other header options I might be overlooking?

BTW: The LT1 has GTP stage II heads, Comp Cams TS-224XL, and may possibly have a D1SC procharger on it this coming year.

 

There are hooker longtubes but I had problems with my hooker shorties and LT1. I fixed it, or at least made it better, by grinding/sanding down the area of the header that mates to the head.

If you get a supercharger, then I think it would be a good idea to go ahead with longtubes.

I would suggest looking into turbochargers. Turbos work best with automatic cars and you could run a lower gear ratio, like 3.23/3.08/2.73, because turbos like to spool. You would have a slightly stronger rear end and better highway gas mileage.

And if you went with rear-mounted turbo, you wouldn't need longtubes, stock manifolds actually work best for rear-mounted turbo applications because more heat gets to the turbo that way. Wouldn't need an intercooler either.

 

The main reason that it would be about a year before I put forced induction on the car is because I want to really research my options and go the best route. Because of simplicity, right now I'm leaning towards supercharging because I know next to nothing about turbochargers, but I will look into them. Odd that the rear mounted turbos like manifolds better, I would have thought that the faster moving exaust gasses from the headers would help the turbo build boost.

I was thinking about grinding the SLPs to get them to fit better, but if I ever decided to switch to longtubes or manifolds the resale of the SLPs would take a dive. In the meantime though I would like to find a decent alternative to the SLPs, and if the hedmans will do the job better then I could sell the SLPs for almost double the cost of the new hedmans.

 

With the setup you have now, I think *think being key word* you would see a gain with hedman longtubes.

 

If I grind the 1 3/4" SLPs to the point where they're not blocking the exhaust ports would they make more, less, or equal power to the 1 5/8" longtubes? I'm trying to search for an answer but I'm not finding anything on the primary size vs. header length issue.

 

I appreciate Firebat's input but can anyone tell me for sure the drawbacks or advantages of decreasing primary tube size and increasing primary tube length on a 400+ hp engine? I read through the "More than you ever wanted to know about BACKPRESSURE..." thread and I kind of understand what he was talking about but not enough to help me make sense of my problem

 

Ok.....lets see if my train of thought is on track here.
The way I figure it if you have 1 3/4 shortys they havea certain volume they can flow. Larger diameter/shorter tube. now if the 1 5/8 is an obviously smaller diameter but with a longer tube it should flow beter due to larger volume.After all your only dealing with an 1/8 inch difference in pipe diameter and the length difference is about a foot (give or take) the long tubes should flow better. Right or wrong..... I dont know only guessing but I'll see you on the highways of Virginia anyway

 

go long or go home.

 

Well that makes a lot of sense. I just can't stand all these header leaks anymore and the d-ports will hopefully solve that too. So that's 3 for the long tubes and 0 for the shorties, looks like my decision just got a lot easier

 

Ive had 2 different brand shorty headers on my car with zero leakage over the last 3 or so years.

Percys dead soft aluminum header flange gaskets, and stage 8 locking bolts are your friend. A good quality donut gasket at the collector will also help prevent leaks.

Lesson I learned over the last year since my new motor was put in...the collector gaskets are made fibre-wound and solid metal. The fibre wound ones would loosen up, fall apart, and create a leak. I went through 2 sets of those. Ive been using a set of solid gaskets now for the past 4 or 5 months with not even a tick in the exhaust

Longtubes still flow better

 

Dont forget your locking header bolts. The ones with the "E" clips on them.......money well spent if you put headers on anything!!!! unles you get bored eazy and like doing things over and over