[poncho-mike]

I have a 1972 Lemans convertible w/455HO 4-spd. I got it without the original drivetrain, so I've been accumulating parts for it over the years. The car was shipped 4/15/1972.

I've managed to pick up a number of hard to find parts over the years, but some of the dates don't match up well with a car that was probably built in late March or early April.

First off, for a typical production car that is somewhat rare, how far ahead of the ship date should the motor parts be cast or manufactured?

Here is what I have so far: Any thoughts on how well these match up?
- Block: WM coded 455 4-bolt block, B292 date code
- Alternate blocks: May 1972 and January 1973 SR 455 4-bolt blocks
- Starter: 1B11 1108436
- Carb: 7042273, dated 2031
- Heads: 7F6. I have I111 heads and early March 1972 heads
- M22: I have an early M22 out of a 1972 Trans Am (Aug or Sept date)

Which would be better, a correct coded non-original engine block (with dates that might be too close) or a SR block dated after the car was built?

I'm open to opinions.

Thanks.

[pggto]

That's a very rare car! I don't know the production numbers off hand, but I think it's less than 20?

Block is tough call, an original block would have a VIN stamp on it, you might be better off with an SR block.

I sent this post to someone I know who is pretty knowledgeable on these cars.

[unruhjonny]

If you have a correct model year WM motor, that to me seems to be a no-brainer.
The fact that this block predates your car's build date is even better!

SR blocks are great replacements when a correct code block cannot be located - but contrary to the way many people seem to do the SR block thing, these should be dated significantly later than the car's build date.

Unless my memory fails me, top end vs short block dates tend to differ;
I believe most heads slightly predate the block casting date, but I seem to recall reading of several examples where the top end (or even a single head) is dated later.
In similar fashion, I have read of original engines where both heads predated the block by a spell.