Re: 396 Build Up
Kurt;
I just happened to have an original 402 L78 piston & pin out in my shop. I just checked the weight on it with my digital scales: 833 grams for the piston and pin. (The 2287F's in your engine now are going to be even heavier than that, but I couldn't track down the exact weight on them)
The first KB piston (9948) checks in at 832 grams for piston & pin.
The second (9949) checks in at 901 grams for both, but note that it's a .580" solid dome piston. That big knot of aluminum on top does add weight, but you can have them lightened up for a nominal fee.
For comparison's sake, a JE 258207 piston (44 c.c. dome) comes in at 799 grams for piston and pin. As you've probably already found, unfortunately they're not listed as available for a 4.165" bore, and they're ~$400 more expensive than the KB's anyways.
I just did some quick calculations on KB's website; the 9948's would give (approximately) 8.53-1 with a 119 c.c. chamber and 9.2-1 with a 110 c.c. chamber. The 9949's would give 10.6-1 @ 119 c.c and 11.7 @ 110 c.c.
At this point you need to find out what c.c's your heads are so you know how much dome you're going to need, then you can go from there.
Eric
p.s. re: sizes--I have a set of KB's here now that were dead nuts on the money for size. fwiw.
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