[ffindling]

I believe it is based on a .030 over 390 block which when combined with a 4.25"
crank would yield 444.5 CID. The crank
is a 2.2" journal for 6.7" BBC rods. This gives a rod length/stroke ratio of 1.576.
The combination is a bit undersquare, but
it shouldn't be a problem unless you want
something that will twist beyond 6,000.
Should make for a good torquey street
motor.

....Fred