427 engine - is it a 4 bolt main block??

[Joe L.]

Re: 427 engine - is it a 4 bolt main block??

Thanks Ray and Bill.....its a four bolt block. I think I should continue my research on this engine now - while I have some big block guys on this post.

I am trying to attach a pic of the block casting number....legible digits are 993289 (maybe the last 9 is a 0 or 8??). I can find no such big block number in the few books I have. I find 3999289...that's the closest.

The pad is completely blank....and the block itself does not look like it was ever painted.

I have spoken with the original owner of the car...he has very good recall...remembers the exact date that he took delivery of his new 1966 vette. He says he purchased the new long block from Motion Engineering (of Baldwin Motion fame) in 1973 or 1974. He ordered an exact replacement for the original 427/425 motor except that he wanted to upgrade to aluminum heads (which it has). Says he never cared about any part numbers and did not verify bore/stroke/whatever...just dropped it in and ran. He does remember that the darn motor cost way too much!!

I would think that Motion would have identified the motor in some way - in case of customer service or complain needs - or just for their own production/inventory reasons....but I don't see any stamping or paint markings on the block.

The motor has sat undisturbed in the car for about 30 years with almost zero miles during its second ownership (deceased). I am third owner.

Perhaps its a 454...anyone got some facts (or theories) for me??

Dave-----


The number is 3999289. This is a 4-1/4" bore big block that was in use from 1972 through 1975 and likely thereafter for SERVICE use. Folks think of the 3999289 as being a "454 block". That's because all PRODUCTION applications for it were 454 cid engines. However, this block could have been and VERY likely was used for 427 SERVICE applications manufactured during the 1972+ period. This, of course, is exactly when your engine apparently originated.

The only INTERNAL difference between a 427 engine and a 454 engine is the crankshaft and the pistons. So, using a 427 crankshaft (i.e. 3.76" stroke) and 427 pistons in a 3999289 block yields a 427 cid engine. Just about ANY block originally used as a 454 can also be used for a 427. However, the opposite is not necessarily the case. A 454 crank cannot usually be installed in a block used for most 427 applications without grinding clearance on the lower end for the longer stroke crank. The exception is the 3963512 block which can be used for either 427 or 454 applications.

[Dave E.]

Re: 427 engine - is it a 4 bolt main block??

Joe...please go back and look at that block casting photo again....(won't let me upload it again)...the digit in front of the 2 seems to definitely be a 3......not a 9?? Thats why I concluded it was not 3999289. Dave

[Joe L.]

Re: 427 engine - is it a 4 bolt main block??

Joe...please go back and look at that block casting photo again....(won't let me upload it again)...the digit in front of the 2 seems to definitely be a 3......not a 9?? Thats why I concluded it was not 3999289. Dave

Dave-----


I looked at it very closely. I agree that the 4th character does look very much like a "3". But, if that's what it is then it's a foundry mistake which is very unlikely for something like a casting number for a block. If it is actually 3993289 then this is not a cylinder block, at all; it's a seat cushion trim (i.e. seat cover) for a 1972 Chevrolet truck.

[Rich P.]

Re: 427 engine - is it a 4 bolt main block??

Dave-----


I looked at it very closely. I agree that the 4th character does look very much like a "3". But, if that's what it is then it's a foundry mistake which is very unlikely for something like a casting number for a block. If it is actually 3993289 then this is not a cylinder block, at all; it's a seat cushion trim (i.e. seat cover) for a 1972 Chevrolet truck.

Well that fits for this thread...

at first it was thought to be a truck block and second you are supposed to feel the power of a big block in the seat of your pants. So it could be a truck seat cushion

Rich

[Jeff G.]

Re: 427 engine - is it a 4 bolt main block??

Joe, I'm amazed at your ability with part numbers, it's almost scary. What resource information do you use?
Jeff

[Joe L.]

Re: 427 engine - is it a 4 bolt main block??

Joe, I'm amazed at your ability with part numbers, it's almost scary. What resource information do you use?
Jeff

Jeff----


I have a variety of references that I use in combination. There's no single-source reference that has it all in one place.

[Dave E.]

Re: 427 engine - is it a 4 bolt main block??

Joe......I am cross-eyed from studying that 3 that you tell me is really a 9.....still looks like a 3.....a truck seat cover uh??...hope its the high performance version....otherwise I overpaid. Thanks for your research. Dave

[Joe L.]

Re: 427 engine - is it a 4 bolt main block??

Joe......I am cross-eyed from studying that 3 that you tell me is really a 9.....still looks like a 3.....a truck seat cover uh??...hope its the high performance version....otherwise I overpaid. Thanks for your research. Dave

Dave----


I agree; it looks like a "3" to me, too. As I say, if that's what it is, then it's a foundry error because there never was any block with the casting number 3993289. That number belonged to the truck seat trim I mentioned.

[Clem Z.]

Re: 427 engine - is it a 4 bolt main block??

Dave, there are two bosses above the oil filter, on a 4-bolt block those are drilled and tapped and have fairly large pipe plugs in them. 2 bolt are not drilled and tapped in that area. Should be pretty obvious.

those large tapped holes are for a remote oil cooler and i never saw a 2 bolt block with these tapped holes