98SuperchargedLs1

iTrader: (1)

i have a 65 chevelle with a ls2 custom turbo setup.. i had hardly any room to work with any kind of stock manifolds, headers so i had to do the log manifolds and they used sch 10 stainless on the whole thing front cold, hot and crossover and i did 500rwhp and 540rwtq on 7.5 psi stock motor built 4l80e garrett gt40 turbo.. id go with the log mani's

CarsandWomen

iTrader: (19)

If you have some truck shorty or know someone who does, try em before you take my word for it because Ive got a 4th gen. The fact I state is theyre way bigger and dont fit mine like normal mani's do and im not familiar with 3rd gen engine bay.

maybe if you build the log and step up the runner size after every cylinder? the idea of that would be do move the highest pressure'd area out of the log and down into the hot pipe where it may not be so prone to split the welds of the log.

One thing too, I cannot stress enough the value of preheating before you weld, Dont let the part get too hot during the welding, and find someplace to have it heat treated post welding, these things are far more valuable than most people realize.

Phil99vette

iTrader: (11)

OP,
Are you building the log headers or buying them?

Blownz28man

iTrader: (2)

Really don't know anyplace to buy logs. Serioursly looking at building logs or buying the stainless works headers.

That is an idea. Manifold on driver side, Crossover to passenger log on passenger with crossover under and have a merge. Humm..

Theres just so many mixed emotions on Log manifolds. And the stainless work headers are pricey (Dont yell at me I know..)

Phil99vette

iTrader: (11)

If your going to build headers, take the time and build a 4 into 1 of 1 5/8" tubing.

Ping King

iTrader: (20)

just find some type of cast iron manifold and use it. Saves money, time, and they are indestructible.

CarsandWomen

iTrader: (19)

if you can find a used set of shortys for 50 or 100 bucks, chop em up weld em back together, use em how you need to. I think thats what i may do to mine. If it does come to building logs, just put a little thought into how the flow will be and weld em right. If they dont work out, change em later. presumably youll be done with the build for a few months and money may be a little more plentiful .02

98TA6.0

iTrader: (42)

that is an idea. or you can do it right the first time and enjoy driving it rather than putting it back under the knife when you are unhappy with it after you did all that work on it. I'm not sure why everyone is so intimidated by tubular headers. they are a bit more work to fab and alot more welding but the end result is amazing. just use the right metal and make sure a skilled pro welds them so there arent any cracks later.

kmracer

iTrader: (1)

use 5.0 shory headers.

MUSTANGBRKR02

iTrader: (91)

Then just cut them as close to the flange and weld on a LS flange?

98TA6.0

iTrader: (42)

thats actually a good idea. never thought of that. is that a joke or are you serious?

kmracer

iTrader: (1)

no, thats serious. you can get em on ebay for way cheap, 68 bucks plus shipping. then vband one end, and weld ls flanges to the other. you could even run the stock 5.0 headers, im not sure what the primary diameter is, but im guessing they're 1 1/2", which may or may not be a good thing depending on your setup.

98TA6.0

iTrader: (42)

I'd like to see a write up on how that's done. pretty good idea though

kmracer

iTrader: (1)

well... im at a crossroads with mine. its either manifolds or this option. i cut my manifold, tried welding it, and the welds cracked when they cooled. it really wouldnt be hard though. its just a matter of welding the flanges on.

lunati397

Ditch the power steering and get a pinto rack it will clean up nice or keep power steering get rid of the big *** steering box get a tubular k member (you want one anyways) and get it with 4th gen rack and once again it cleans up nicely

lunati397

im in the same boat but im going with a pinto rack

MUSTANGBRKR02

iTrader: (91)

Preheat the manifolds then post heat and a slow cool to allow the welds to hold. I used stainless tig rod on mine and it welded pretty good. I also cleaned the area thoroughly with a wire brush and acetone first.

yelo04goat

iTrader: (11)

there are a few ppl that have been 9s on a stock mani with crossover and a log... i know of one that did that in a 4800+ lbs truck.... so they may not be the best for flow but it does work..

i will be running a setup like its soon enough.

rotary1307cc

iTrader: (5)

either preheat and post heat like this or keep as much heat out as you can


weld a very short burst (1-2 seconds) then immediately peen the weld to relieve stress, you will notice there will be no popping and cracking

continue to peen it until it is cold again, then repeat, it takes awhile but it works

CarsandWomen

iTrader: (19)

very wise, get the manifold up to about 450deg F and keep it at or above while welding. Dont let it get above 600deg F during the weld but after the welding is complete, do not let it cool below 450. Instead, heat it up to the 550 to 600 range and keep it there for a good 30 min to an hour. get a wooden box and fill it with sandbox sand from the hardware store put sand in the bottom. keeping the manifold hot still, put it in the box and dump sand on top, slow cooling the part. this is known as a Post Weld Intermediate Heat Treat. and pretty much every aspect of it is designed to keep from cracking, it is also designed especially for situations like this when you are welding together two different metals, ie Stainless and Iron.

you can have a proper Post Weld Heat Treat done in a furnace but this should do the trick.