Re: Best place to get a rebuilt marine engine?
There's more to this than simply swapping cylinder heads. The piston selection must be known, in order to know which cylinder head to use..... or IOW, the cylinder head choice should influence the piston selection.
Also, there are several SBC cylinder head casting numbers to steer clear of.
Do a Google search for SBC cylinder head casting numbers....... some of the light castings are listed.
Typically any with five scallops along the lower area should be avoided.... such as this one.
This heavy casting shows only two scalloped areas.
We'll commonly see the 64cc chambers being used in the mid 80's, and we'll see the 76cc chambers being used on the earlier engines.
The two pistons that we'll see will be either the full dished, and/or the Flat Top.
Each requires a different combustion chamber volume in order to remain within a C/R that best suits Marine cruiser use.
Many rebuilders simply grab a full dished piston without giving this much thought!
I'd recommend that if you are custom building one, that you steer clear of the full dished pistons.
Contact a piston supplier, and tell them what you are building, and ask for their recommendation for a Quench Effect piston.
Either cylinder head volume can be used...... just tailor the piston style/volume to the cylinder head volume and desired C/R.
It's that simple.... and no other mods need to be made.
With a Q/E, the C/R can be increased some without added risk of detonation.
If your rebuilder does not understand the Q/E and Detonation potential (for a Marine build), he may not be your best option, IMO.
If nothing else, get your hands on a copy of Dennis Moore's "Small Block Chevy Marine Performance".
A local library can bring this book in for you.
Last edited by RicardoMarine; 08-09-2011 at 10:32 AM.
Rick ... aka Ricardo..... AQ series Volvo Penta repair
28' SDN F/B w/ twin Volvo Penta 5.7L DP's
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