I have a big block in my 72 chevelle that I would like to order some parts for. I can't see the casting number on the back but the engine pad on the front has the serial number of C9S120537 with no suffix code. Can anyone tell me what I have. The heads are 346238, are these any good. I want to build up this motor as it is stock .030 or .040 over right now with a Weiland 7544 intake and a Holley 750 carb. I want a rumbling cam with lots of torque. I need you guys help. Thanks.

Is there a small flat pad right like the other pad above the middle of the waterpump on your motor b/c the suffix MAY be on it??

pdq67

Get on the Mortec website. It has all chevys casting numbers and what they came in for blocks and heads. Or if you are rebuilding it anyway, any machine shop can look it up for you.

If it is a 468 as listed in your signature it is .060 over. If you are rebuilding it you might want to yank it and have the block tested/checked out before buying parts. That would also give access to the casting number and true bore of the motor. If you aren't doing anything with the bottom end and just want to change some top end parts pretty much most BBC (396-454) parts will fit.
The suggestion for info @ www.mortec.com (http://www.mortec.com) is a good start. Good Luck.

The head casting numbers refer to a 75-87 454, open chamber. There should be some more numbers on the engine pad just in front of the passenger side head, that would give you more info on the motor itself.

Originally posted by pdq67:
Is there a small flat pad right like the other pad above the middle of the waterpump on your motor b/c the suffix MAY be on it??

pdq67 pdq67 hit it right on the head..sounds like a mid/late 70's 454..the engine code will be above the timing cover,under the bypass hose.Heads are peanut ports...

Use one of those angled mechanics mirrors to read the casting number...works great and easy to see with the mirror.