My 67 442 with a 455 has headers installed by the previous owner. I want to change back it to factory style manifolds. Are the repops any good? PartsPlace has 3 different versions listed, X, W and XW. XW being the most expensive. Can someone tell me what the differences in these manifolds are?

 

Looks like I read the ad wrong, X is one side and W is the other side. Are they ok for a repop?

 

I have W Z manifolds on both my 68 and 72 442 both with 455 engines. W manifold on drivers side and Z on the passenger side. I really cant tell you want the difference in the ones you are asking about. I got my manifolds from Thorntons and they really fit great and I have had no problems. Thorntons also has the polished headers for the 455 engine.

Engine | Thornton Muscle Cars

 

Buy the Thorntons, yes they cost more but they are a quality product..Parts Place will sell anything they can to make a buck..not saying everything they sell is inferior but on this question…they are..

 

Actually $10 cheaper on Thorntons website but I wonder if everyone is selling the same casting.

 

Will the W/Z manifolds for a 69-72 fit my 67?

 

I think you may need to call Thorntons and ask that question, they are very knowlegeable oldsmobile folks.

 

I have them on my 67 vista and they fit fine.

 

Do you want correct manifolds or the best-flowing manifolds? Correct manifolds for a 1967 442 are casting 389268 W RH (this is NOT the 1969-72 W manifold, by the way) and 389269 X LH.

The 402294 Z RH and 402295 W LH from the 1969-72 cars will fit and flow better but are not correct. These manifolds have internally-divided runners, unlike the earlier ones.

 

Actually the WZ is more correct for my 72 455 engine plus like you say, they flow a little better. My car is far from being a numbers matching anyway.
Would you say all the different offerings on these manifolds are probably from the same manufacture and I can just simply look for the best price and availability?

 

I have a nice set of wz manifolds. Message me if you are interested.

 

One thing I would verify if you go the repop route is the length (or existence) of the divider wall in the center. I've heard over the years that the repops either, 1) don't have the divider, or 2) it's there, but only at the machined face and doesn't extend down the runner in the casting like the originals. If this is true, I'd consider them visual representations only with reduced performance from a set of originals.

 

The factory W/Z manifolds have divided runners internally that improve flow. I have not inspected repro W/Z manifolds. The aftermarket "W/Z" small block manifolds are not internally divided. There isn't enough room in the small block manifold. That divider is for appearances only and is only about an inch deep.

 

I picked up a set from Restoparts and they look great. Casting was good and finish is good. They also bolted right on with no issues.