Hey guys, I'm on a pretty tight budget for my LT1 swap. As a temporary thing I was just going to use my stock thirdgen exhaust. Today my dad was thinking maybe we could use the LT1s exhaust manifolds with the LT1 stock y-pipe. I know the complete y-pipe won't work, but he was thinking of just using part of it and then fabricating the rest. Will the LT1 manifolds fit in the car? I know I should get headers, all in good time. I don't have alot of money and I Just want this car on the road. I would rather sacrifice some horsepower and just get this car on the road now since its been parked for 2 years.

That would be a big negatory, where the 4th gen manifolds exit out it would hit the a-arm mounts on the crossmember.

use the factory thirdgen manifold and all of the exhauust will b olt up.

Thats the plan now. Just need a O2 bung welded in the y-pipe.

Eventually I'll have the Hedman d-port shorties, but they are backordered and I don't have time to wait around.

Better get two O2 bungs, gotta have one for each bank.

Driver side stock thirdgen manifold has a bung on it.

Geez...I just thought...that thing is gonna be choked down with the third gen manifolds on it.

Yes I know. When Uncle Sam decides to pay his war fighters a better salary, I will be able to afford to spend more of my money on car parts. Until then, I can't afford to do much.

The car has been parked for two years.. back when I blew a head gasket or cracked a head. I just want the car on the road now, I'll worry about optimal performance later.

I just put a LT1 in my car and used the 4th gen Manifolds. It took using the third gen and 4th gen y pipe with some fab. but it works fine. When on a budget do what you can with what you have. Everything fits great.


Good luck.

When you used the fourth gen manifolds did you have any clearance issues with anything (Mainly the crossmember, or the steering set-up)? Did you use an aftermarket crossmember?

I have an 83z28 and have no clearance trouble, no modding of any type to use the 4th gen stock manifolds except the Y-pipe.

Ok, so they fit. I was worried when I read someone else said they wouldn't fit. I want to use the LT1 manifolds until I pick up some headers.

Looking at my '97 Z28... the manifolds look like they are 'ducted' roughly the same as a 3rdgen manifold was, so I don't see why it wouldn't fit. They fit tighter to the engine as well.

When I tried mine, it came out with part of the manifold hitting the crossmember, thus the reason I went with headers.

Hmmm...so in some 3rd gens with an LT1 engine the LT1 exhaust manifolds will fit and in some 3rd gens the manifolds won't fit? LOL

Just to get it on the road, use the thirdgen exhaust, no modifying, cutting, welding needed. 4th gen exhaust still sucks.

id say buy cheap headers at least . . . Why put a LTX in if you dont plan to optimize its potential performance?

No, the LT1 manifolds won't fit at all, the exits come out right on the a-arms, at least they were going to on mine, and the driver side was hitting the k-member.

For those that were able to use the stock LT1 manifolds, what did you do about the big flange on the drivers side (that connected to the LT1 cat)?

I think I'll have to have a Y-pipe fabbed up anyways, is there a way to avoid using the huge flange?

I used the 3rd gen y-pipe and cat. w/4th gen flanges on the end (where it connects to the manifolds).

So do the 4th gen manifolds work with the ltx swap or not? I'm about to pull the lt1 out of a 95 donor and need to know please.

I'm in the midst of an '95 LT1 into '89 Iroc-Z swap and I can tell you that the LT1 stock headers do not fit. They dump way ahead of where the stock 3rd gen ones do. They also have a different connector, since one of them bolts directly to the catalytic converter. I'm using a set of Edelbrock headers meant for a 305. They are a little too small in diameter in a few spots, so some minor porting is required. If you have a 350, your headers should be fine.