Originally Posted By 71_Demon
Its a 383, bored .040, flat top pistons forged crank, 10.1 compression

-stock 452 heads

FYI, A 383 with flat top pistons and stock 452 heads will have a lot less than 10:1 compression. More like 8.5:1. The domed KB400 piston would be close to 9:1 with that head. That said, any plug with close to a stock heat range should work.

In theory, there is no difference between theory and practice. In practice, there is.