Ok, I am in the process of building a healthy LT1 355, not stock but not too wild either, for a project of mine. The problem I am running into is the exhaust. I am limited to stock manifolds, up to 1-3/4 shorty headers, or 1-5/8 long tubes. Everywhere I have seen says to run the long tubes but the small primary size does not fit the LT1's D-shaped exhaust port very well, and I am leaning towards the shorty headers. Now on to my many questions. What kind of performance can I get before the shorty headers become too much of a restriction ? For the couple times a year when I do make it to the track I will run an electric cut-out, so do I build the engine (cam selection) for the track with the cut out, or for the 70 % street time through full exhaust ? Also, for a further note, I will be spraying the juice from time to time but no more than a 150 shot.

So with all this being said, anyone have any recomendations for internals on this, without getting exotic ?

Thanks,
511 ERT

 

There was a huge debate on the subject a few years ago on this board as to whether or not long tube headers produced a significant gain over a shorty header and from what I remember the gains between the two were minimal if anything (given the two examples had off road y-pipes).
If it were me I'd stick with a larger primary/shorty header and a cut-out. I'm curious as to why you have to stick to those guidelines?

 

First off, thanks for your reply SS RRR. Second, I was actually trying to avoid that question because I don't want people to get off the topic and start flaming me for it. I have been around a while and on several different boards and seen it happen for not having the "appropriate vehicle" for discussion. But since you asked, my (slow moving) project is a '94 SS S-10. I don't know if you are familiar with those trucks but in order to run a full length header with a larger primary, the headers have to exit the fenderwell and run down the outside of the chassis. The drawback to this is that you have to run skinnies up front and the steering is still limited. With this being a mostly street vehicle, I don't want to sacrafice my steering or be limited to the tires that I run. ( I still want a "stock" looking truck)

Thanks again,
511 ERT

 

Totally understand. I think you should be just fine w/ a shorty header. Good luck with it. I've always loved and respected conversion projects.

 

agreed, I think it's an awesome idea to put a V8 in an S10, especially an LT1 - good luck with the build - post some pics when you can

 

I run my car with 1 5/8" midlength round port headers. Bench racing says they are all wrong but reality says they are not working too badly. I do think it would gain with some nice longtubes though. Just really saying that in my experiance 1 5/8" and midlength are not the big handicap they are made out to be.

The 4-tube are the ones I have run most of the time with this heads/cam setup. I tried the Tri-Ys for awhile and really noticed no difference either way.

http://s120.photobucket.com/albums/o...t=DCP_0546.jpg

http://s120.photobucket.com/albums/o...t=DCP_0538.jpg

 

Bottom line is the primary tube size is what will determine a restriction. A "long tube header" will more or less tune the torque curve to give a higher peak torque. A shorty header will most likely have a flatter less peaky torque curve.

My advice, go with the 1-3/4 shortys.

 

u can use these SBC 1-3/4'' S-10 HEADERS 3" COLLECTOR from s10.com or jegs i think.. they have done great for me iv used them on 4 s10 conversion and now on my 5th 99 sanoma this time i went with the stalh fender well exit great fit and big lol

 

Thanks guys I definately feel better now about going this route. I was beginning to debate on going through with the S10 thing or not for this reason.

Maverick.... I'll try to get some pics up some time soon, but right now I'm in the "build the motor 1st" stage, and I'm doing this on a family man budget. So it will probably be early summer, at the best, before I start putting this thing in there. I'll keep everyone updated though.

markclrks..... thanks for the heads up on those headers. A buddy of mine pointed me to the Sanderson Headers and I have been looking into them a bit.

96capricemgr.... Like they say, pics are worth a thousand words. I like the way those tri-y's look. Pretty trick. Thanks for the input, I too have done a few things that everyone said would not or did not work. A guy I know once told me that people like to say that things won't work, when they actually mean that they haven't found a way to make it work for themselves. This person has a sub 9 second '96 Impala SS, full street trim, with a race weight of around 4500#, running a big ol' supercharger AND doing it on a GM LT1 ECM !! (And yes, I can vouch for this car !!)

All in all, sounds like I'm going with the 1-3/4 shorties !
Thanks again everyone.

511 ERT

 

You know Jeff? Tell him I said Hi.

 

Yeah, I know Jeff. Not real well though. I went down to SSHS7 with him last year and I was supposed to go to the LT1 shootout with him but he was having a few problems with his car and didn't decide until the last minute to go. He is the one I was talking about when I PM'ed you earlier. Anyhow I will probably be talking with him here pretty soon so I let him know you said hey.

511 ERT