Is it a 427 or a 454

[jack alexander]

Besides the obvious internal differences between a 427 and a 454,
are there any external differences between a 427 and a 454, excluding all the ID numbers?
Jack

[Craig S.]

Re: Is it a 427 or a 454

Jack - since you are excluding the obvious casting numbers on the block and date coding locations, the only item that comes to mind MAY be the oil cooler port drilling over the oil filter boss. This would only apply to 4 bolt blocks anyway, but I am not sure if the early 70's 4 bolt 454 blocks had the same large npt drilling as the 60's era 427's or not. I have an 89 vintage crate LS6 with 4 bolt, and it does have the drillings BUT they are much smaller npt...like 3/8" or so as I recall, not the large 3/4" npt like on the 4 bolt 427 blocks. There may also be other slight casting and mold variations, but I am not sure...Craig

[Wayne W.]

Re: Is it a 427 or a 454

454s were externally balanced so the balancer on the front and the flywheel will have a large heavy cast in weight on them.

[Craig S.]

Re: Is it a 427 or a 454

Good point Wayne, I guess I was thinking of the bare block vs assembled engine..... Craig

[jack alexander]

Re: Is it a 427 or a 454

Thanks Wayne and Craig:
Wayne, your answer set off an old memory. I remember hearing that so long ago that I had forgotten it. Thank you both for your help.
Jack

[John M.]

Re: Is it a 427 or a 454

A late 1969 427 casting number is 3963512, 1970 and 1971 454 blocks were the same 3963512 casting number as the 1969.