91_5.7_TPI

iTrader: (2)

I plan to do a LS1/T56 swap this summer. I don't think that will have enought to afford headers, though. At least not good ones like I want. So, what should I do for exhaust? I know I can use the stock manifolds and that I need at least a single 3" exhaust to flow the LS1. Will the 4th gen pipes bolt to my car? Or, do I need to get a cat-back and then bolt that to the headers when I get them?
The downside is, I think I want LTs, but any ST or manifold cat-back won't bolt up to LT cat backs. So, what should I do, other than find a way to make enough to afford the LTs

snowbird88gta

I think the best way to go right now is find an ok guy to custom make your pipes. Just use your manifolds (I think it is 00 and up that look like shorties anyway) and then let him make you something that will be decent until you get the cash to buy some LT's. This is what I did and I got my pipes made for about $100. Hope this helps some.

91_5.7_TPI

iTrader: (2)

Thanks. That is what I'll do. I would like to find someone with a mandrel bending to make them flow the best.
I think that the 00 and newer are similar to shorties.

1bdbrd

iTrader: (1)

why go custom made? just buy a good catback. the y pipe is what connects the headers to the catback. and yes a 4th gen catback will fit, i have one on my car.

run some stock 01-02 ONLY manifolds for now to a y pipe, to a 4th gen catback. then later on, buy some long tubes, the matching y pipe (or have it custom made) and just run it to the same catback you have now.

snowbird88gta

Why? Because it is a pain after you have just finished a project that is this big. Also, why not just go ahead and spend the 100 bucks. The catback system (not to mention the y-pipe) is going to cost a lot more than that. Also the fourth gen system might work but did you have to fight with it any? Over all it is just a waste of time and after doing an LS1 swap your pretty much ready to be done with cars for a while (minus the driving part )

z28evans

Howdy,
I made a y-pipe and bolted it up to a Flowmaster 3 in cat-back system. Low budget, do it yourself setup.



more photos here: http://www.bubbadrift.com/album/thumbnails.php?album=26

good luck,
james

shr00m

iTrader: (2)

Hey, where did you pick up the triagular flanges?

Thanks,

Kevin D.

z28evans

damn - a triple post, you must really want to know

I got the flanges from a person that i bought the exhaust manifolds from. They are stainless steel, not sure who makes them - but they are not very good. I had to redrill the holes bacause they were too small, and one of the flanges doesn't have the center hole lines up very good. I would recommend taking a factory y-pipe and cutting the flanges off of those if you can't find someone that sells them. The person i goit them from had bought them to make a custom turbo kit, so that may point you in the right direction.

James

five7kid

iTrader: (14)

There, it's just a single now. . .

shr00m

iTrader: (2)

Sorry! Site was stalling (like it's doing now). I thought I checked for extra messages.

I've got a stock y-pipe under another car. I need some to attach directly to stock manifolds, not the cats. I'll have to look and see if they're the same flange pattern or not.

Thanks,

Kevin D.

kjvail1204

iTrader: (4)

Ok im just currious, I am droping a 98 LS1 into my 88 do i need to have 98 headers/y pipe, or can i use a set that covers 88. I mean I would assume that the exhaust ports are in the same area. I am just trying to get an answer so i can start shoping.
My problem is I jsut purchased a 3" flow master set up for my 88 with a 350 in it, I dont want to have to get an all new cat back system. I just want to hook it up and go.

five7kid

iTrader: (14)

Same area (the engine compartment), but no where close to being the same.
All that work to get the LS1 in, then cheap out on the exhaust???

Your cat-back can be adapted to work with LS1 exhaust. Just have a y-pipe made from the LS1 manifolds to the cat-back.

tlove

If you can't do headers then go with 2001+ stock exhaust manifolds. You can normally find them for a reasonable price on buy/sell boards since there are a lot of folks putting headers on their LS1 cars. Ports are totally different on LS1 as compared to TPI so you have to buy something.

You will have to find someone that does custom exhaust work to fabricate something between the manifolds and the rest of the exhaust. If you don't know anyone ask around at the local auto parts stores. They normally know who the local guys are that do good work. I wouldn't suggest the chain shops but that's just me.

Since it's a T-56 you might also want to consider a transmission mount made for a straight back exhaust. It should let you eliminate that big bend (passenger side) in the stock exhaust routing.

kjvail1204

iTrader: (4)

I meant on engine location I obviously know they are in the engine bay, two I didnt cheap out, I didnt know I was getting the LS1 till yesterday, I had the exhaust for my car, the reason im trying to find a in exspensive fix is I am in the military, and have 4 kids, buget is kindda thin, Im not rolling in money as most people seem to assume on here.
I already go my answer from someone else who wasnt quite as rude.....thanks anyway

five7kid

iTrader: (14)

No intention to be rude. There just isn't any tongue-in-cheek sticky.

There probably was an assumption of general knowledge of the basic differences between GenI/II SBC's and Gen III. Apologies for being presumptuous.

Fully understand the military/multiple-mouths/single-income limitations. Been there, still living a good part of it. Unfortunately, LS1 isn't one for the faint-of-budget.

Manifolds/custom y-pipe is a reasonable approach. After all, these engines made pretty decent power as-delivered through manifolds.

88 350 tpi formula

iTrader: (9)

I used manifolds on mine.

using the 2000-up really makes no differance IMO . although this is what I used since they happened to be what I got.

the older egr ones I think are the same these just never had the mounting for the egr tube drilled (if I ever have some stupid time I should check casting numbers)


I made my flanges since I never got the cats to hack them off of. well..... that's a whole story too


anyway I used 3/8" steel plate from the local metal yard and traced the gaskets out. drilled a 1/2" hole in the center and installed a bolt... then I put the flanges in the lath and got the center cut out. (a good! hole saw would work but will take time and lots of oil) then I took and finished the center using a deburing (sp) bit

I used a band saw to cut the shape but again a good hack saw and a vise with some time will do just as well.


if I get a chance I will look for the pictures of the y-pipe. once I was done you would swear the flanges are from the cats

Klortho

The 2001+ manifolds flow better than the 98-2000 ones so if you can find a set (and you can find them cheap people always want to ditch these) you will be better off, and then having a custom y-pipe fabbed up...it's possible you may be able to get away with using a 4th gen y-pipe but would require lots of work.

five7kid

iTrader: (14)

I was going to say, 2000 still had EGR.

88 350 tpi formula

iTrader: (9)

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88 350 tpi formula

iTrader: (9)

I was asked a question today so I thought I would post this up...

I checked and the 98-02 have the same casting number. the later just did not have the egr drilled out on the pass side.

now if that makes a real differance in flow hold on for this....... the gmc w4500 med. truck (delivery type of truck "cab or cab over") with the 6.0 uses at least the same drivers side manifold and has no air injection hole drilled or o2 hole drilled. so if you do a swap and can find this manifold I guess this is the one to use. I never checked the pass side but... who knows I blocked off the o2 and air on the drivers side and if I hade a choice this would have been it.

If I remember I will get a picture to prove it too!