This is a motor I've been thinking about for some time, already have most of the pieces.
A flat top piston would put the compression pretty close to 10:1, depending of course...….
So, for a 10:1 iron head motor with good quench (915 heads), how much cam duration would I need to
be able to run 91 pump gas ? Assuming decent cooling, not too lean, smooth out the sharp edges, etc.
If you mean a 440 rod in a 400, it wont fit, it's about .400" longer. I mentioned in another thread that a budget 400 can be built using a .040" over 72 style 440 piston making a .020" over 400 with the same deck height as a 68-9 383.
