5.7L 350 ci Heads and intake matching

[Leedanger]

Cracked heads and block.
MCM 5.7 Litre Serial #0K104547
2BBL MercCarb ThunderBolt V

The cast # on the heads is 14096217. Are these heads "vortec"? From what I found these were just crate motor heads. I didn't think that they were but they do have the center valve cover bolt holes which I thought to be the give away. I found a much older replacement long block and I would like to just take all the externals off ol' cracked magillicutty and put them on the replacement block. The "new block" is merc serial #5424302. and the heads are cast # 462624.

The cracked block also has a 2 piece rear main seal where the replacement does not, will I need to switch that? Lastly, the exhaust manifolds on the old one are the longer "log style" where the originals are the shorter new style (not sure the terminology). Any other "gotchas" anyone knows I am going to run into fi I attempt this here deal?

 

[John_S]

Re: 5.7L 350 ci Heads and intake matching

The 217 heads are not vortec. They are 64cc chamber heads, use centerbolt valve covers, and canted center intake bolts. Common on pre-vortec sb mercruiser. With that serial number, it should be 1 pc rear main seal. 2pc was pre-88. The center risor exhaust manifolds should stay, if they didn't crack.

It is not clear to me what the old motor is that you want to swap parts to, but think the intake will not bolt up, need different coupler, flywheel, starter?

I'd replace with a 5.7L vortec.