Z-X manifolds

[zodiacblueS]

I'm still detailing, waiting for my cam to get in, but I was able to clean up the manifolds. Wire wheels, a lot of solvent and Calyx dressing. They have a few pits, and the castings are really rough. Maybe not as pretty as the Thornton repops, but these are what she was born with. Can one of you wise men explain to me the difference between W,X,Y and Z manifolds? (I know one is right and one is left. :rolleyes: )

[zodiacblue442]

I'm still detailing, waiting for my cam to get in, but I was able to clean up the manifolds. Wire wheels, a lot of solvent and Calyx dressing. They have a few pits, and the castings are really rough. Maybe not as pretty as the Thornton repops, but these are what she was born with.

Can one of you wise men explain to me the difference between W,X,Y and Z manifolds? (I know one is right and one is left. :rolleyes: )

Not sure I'd classify myself as a wise man... maybe a wise guy! :D The W and Z manifolds were used on the 70-72 Cutlass, 442, etc. big blocks. Not sure about 69, but I know 70-72 for sure. 73 and 74 big blocks as you know used X and Z manifolds. The Z manifolds are the exact same as those used on the earlier cars. The W and X manifolds are so close I honestly don't know what the difference between them is except for the letter and part number that's cast in them. There were also X manifolds used in 68 and previous years but those are totally different than the ones used in 73-74. I have never heard of a Y manifold. The same X and Z manifolds used on 73-74 Cutlass big blocks were also on 73-74 big cars with dual exhaust. Maybe 71-72 also but don't quote me on that.

Hope this helps. Your cleaned up manifolds look really good! I like 'em!

[MrRocket]

Gary is right, W/Z manifolds were used in 69-72, the Z manifold continued through 74 and in 73 the W changed to an X and went to 74. Both are supposed to be the best flowing stock units, sorta like factory headers since the ports are divided. I have a set of both and can't tell the difference by looking and no one has any clear info. on one set being better than the other as far as performance. I say use the American made parts as long as you can before going to the Thornton repops. Yours look nice!

[zodiacblue442]

Gary is right, W/Z manifolds were used in 69-72, the Z manifold continued through 74 and in 73 the W changed to an X and went to 74. Both are supposed to be the best flowing stock units, sorta like factory headers since the ports are divided. I have a set of both and can't tell the difference by looking and no one has any clear info. on one set being better than the other as far as performance. I say use the American made parts as long as you can before going to the Thornton repops. Yours look nice!

Good point about them being the best flowing stock units. I forgot to mention that. They are indeed like "factory headers" since they are true dual exhaust manifolds with divided ports. My brother and I put a set of X / Z manifolds on the race car and it's a pretty darn quick car. I know it would be quicker (maybe .5 seconds at most) with real headers but I like the maintenance free, ease of installation, no leak convenience with the manifolds. More ground clearance too which is nice when the car goes on and off the trailer.