I can't find these casting numbers on the intake chart I have. Maybe I'm mis-reading the numbers. Pic of the first intake:

Close-up:

Second intake:

Close-up of second intake:

the numbers on the first one (2806178) is, according to mopar`s bible, a 68-69 440 intake. however, the date code seems to point to a 72 intake. the second number, 3830733, indicates a 75-76 440 intake, which is a thermoquad intake. yours seems to have been machined for a square bore carb. a quick look at nhra`s bluprint specs confirms the numbers. only the 72 date code is a mistery, maybe it is that way because it would be a truck or marine intake.

Thanks for taking the time to look at your references! That would explain it, both of these intakes came on Chrysler Marine M440s. I'm guessing the earlier intake came on a '72 or '73 model (its currently bolts to a '76 block, but the company I got these engines from used 440s in the tour boats for many years) and the other one is bolted to a '76 block (I don't think it had ever been R&R'd). The square bore machining appears to be factory. The earlier intake could have been worth something to someone doing a resto but the '72 casting date screws that up! The '72 car intakes were probably different...