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Old 09-29-2014, 10:56 AM   #15
Weldangrind   Weldangrind is offline
 
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Join Date: Mar 2009
Location: Sardis, BC, Canada
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Quote:
Originally Posted by SpudRider View Post
Because the GS250 engine has a larger bore, you can't put the smaller cylinder head of the TW200/Sierra on the ZS172MM engine.
Please explain. I don't understand why the Sierra head is incompatible with the larger bore, given the same frame of architecture (FOE). The small block Chevrolet SBC) engine will allow any head to interchange with any block, from 265ci to 400ci. The only real difference is cylinder head volume. The bolt spacing remains the same.

The only real issue that comes into play with the SBC is that the FOE is such that the valves are shrouded with anything less than a 4" bore, but the engine will still run properly.

A larger bore in the Zong engine would give the valves even more space. I doubt that the cylinder volume is dissimilar between the two heads. As long as the dowels line up, I can't see a problem.
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