Hey All,

I Have a question about Big Block cylinder heads. I have read a few different things on the 3751213 Heads.

They are listed in the Mopar Engine Book as “Motor Home” Heads.

I have read (on the Internets) where they have a smaller spark plug than a normal BB head, they are low compression heads, they have water pump mounting ports on the head, but I have also read where they we just a normal head and put on cars, trucks & motor homes and where just heads that were made between the “906” & “452” Castings .

I know they have an extra cooling ports, I can see them on the head. other than that the set of “213” heads I have look pretty much like a “906” heads




.

Anyone out there know what the real story is on these heads?

Thank You.

 

Are you going to pocket port or port mach them?
I've read that the ports are the same from the 915 heads until 452 heads came out. I would check the cc of the chambers in each head because they are usually larger, around 90cc. I would cut them to 80 cc and go from there. If the heads pass Magnafluxe, use them.
Note that some heads can't be cut that far because of core shift and the valve cover rail gets a knife edge when cutting the intake side.
good luck

 

Also after 72 or 73 there were no specific motor home heads, there are heads with the same part number using the small or larger spark plugs. I've heard of one 440 having one of each head.

 

I agree.... CC of the chambers were different... Large plug head took a gasket flat seat spark plug ans the smaller plug head took a tapered seated spark plug...

 

All regular B/Rb heads are pretty similar and as long as the combustion chamber size gets you where you want to be in compression they will all perform pretty similar, I wouldn’t get worried about casting numbers