Re: V-8 head part nbr vs cast nbr

Posted by Owen_Dyneto On 2008/9/17 14:25:33

Much as I'd like to be able to, I can't add any information other than what's in the SC, except that I'm relatively certain they did not change compression ratio of the 320 engine when going from machined to cast chambers; otherwise there would certainly have been a TSB or SC about it.

As to the forged crankshaft, friend Randy Berger found one in the 374 engine he bought for parts. He ended up using it in his rebuilt engine. It did have some numbers on it, though I didn't make note of them, though the differences in the two crankshafts are obvious just by visual inspection. I also asked Randy about the last digit on the 374 head casting number; he's pretty confident it's a 6, not an 8.

There are several notations about crankshafts in the SCs as well. Those relating to the 55th series notes that cranks balanced for the 4 inch bore have a "4" stamped onto a milled surface on the end of the front counterweight, the other has a "3". Then there is a subsequent notation relating to the first that says the crankshaft with the #4 stamped may be used for either the 4 or 3-13/16 engine, but those with the #3 can only be used on the 3-13/16 engine. I've never seen similar notations concerning the 56th series crankshafts.