Exhaust manifolds

I bought a set of Buick 3.8 v6 manifolds off Ebay mainly for the drivers side rear dump for when I convert to power steering. I got the whole setup both left and right with a crossover pipe that connects the 2 manifolds essentially making a y pipe out of the set. The drivers manifold hooks into the right manifold which has another port for an exit has anyone used this setup for a single exhaust setup on the passengers side I was thinking it might work but the jeep is at the folks place in the barn and I haven't had the chance to eyeball it yet. Thanks T.J.

 

I don't believe that I have seen that setup. The 78 and newer 231's had exhaust ports that were higher up in the heads. If you run the manifolds on a 225 or early 231 it would effectively lower the exhaust about an inch if I recall correctly. That distance may or may not cause an issue. Where does the tube cross over?

 

I believe it's a later 231 But honestly I haven't checked it has an HEI distributor and an egr valve but I haven't checked the the block numbers. The drivers side hooks up in the rear and runs across under the oil pan in front of the Bell housing to an inlet Port on the right side manifold right in front of the outlet I have the standard manifold on the engine now if this setup won't work I am sure I can do it the only issue might be the cross member but I think when I put the SM420 in that gets moved anyway. Another issue could be drive shaft clearance , won't know till I try I guess, I was just curious if anyone else had crossed this bridge.Thanks T.J.

 

T.J. sorry I really cant answer your question but thought I would share a bit. When we converted our 55 cj5 to v6 and sm420 we used a 231 (odd fire) from a 77 buick regal. We used the manifolds (both rear dump) and y-pipe from the regal. The y-pipe crossed under the oil pan as you mention and then under the front drive shaft (we dimpled it for clearance). We did end up cutting and welding the y-pipe to keep it inside the frame and then ran a single exhaust down the passenger side. Later I changed the motor for a 231 out of an 83 olds cutless. I believe this motor had the right side manifold like you describe but I ended up reusing the exhaust from my previous motor. What about the length of the manifold? Does it extend beyond the back of the cylinder head? When we installed our v6/sm420 we kept the transfer case in the stock position. With the length of the adapter and the longer transmission our engine sits farther forward than a stock jeep v6 would. Just wondering if your manifold would clear your firewall - otherwise I would think the exhaust you propose would work.
I think on the turbo motors they would run the left side exhaust into the right side manifold and then into the turbo from there. I never thought it made much sense otherwise to do this but do think it would make for a simple exhaust system.

 

I bought the set for the drivers side manifold which looks like any other manifold, but when it came and I started looking it ,I started to think about it as a set the right manifold looks almost like a stock manifold that they just tacked another outlet on. I'm in the very early stages of this project and am going to get it running first and do the brake conversion disc in front 11 inch drum in the back. I bought some used pipies from a forum member to piece together an exhaust for now with the manual steering my poor firewall has been all chopped out for clearance but that will be fixed later with pieces from the parts truck. Right now I want to try and get it on the road for next summer while I collect parts to do the rest of the work. I haven't fully decided on anything yet till I see how it runs . Thanks T.J.

 

I have seem manifolds like you described but were 3.8 FWD cars

 

They were listed as coming out of a 1980 firebird . T.J.

 

Interesting that your firewall is chopped up. When I put the V6 in my MB, I only had to "Massage" one little corner with a hammer to get the clearance on the drivers side for the rockerarm cover.

 

If I remember correctly its mainly on the passengers side right behind the head

 

Your setup sounds interesting. In my 45 GPW (231, SM420 at the time) my muffler guy used the two regular Buick manifolds and ran individual pipes up and over the crossmember. He put a Y pipe after the transfer case and ran a single on the driver's side back from there. Works fine and I kept it the same when I went to a 225.

 

Your setup sounds interesting if not a little restrictive. In my 45 GPW (231, SM420 at the time) my muffler guy used the two regular Buick manifolds and ran individual pipes up and over the crossmember. He put a Y pipe after the transfer case and ran a single on the driver's side back from there. Works fine and I kept it the same when I went to a 225.

 

Well I figure it should flow fine , I had a 76 Buick appollo with the same basic setup in it and it would do 75 all the way to the beach for an hour flatout spinning an a/c compressor and pushing through a cat I figure I'm not gonna ask near that much out of it and the pipes are 2 inch front to back and freeer flowing. T.J.