Strange 427 casting numbers (early '68 321 block)

[Wayne M.]

A friend has this block and I understand it could have been found in early '68 Corvettes (up to Jan '68). This one is definitely not from a Corvette, but have any C3 people seen these 'upside-down' casting characters ? And just what the heck is the '2BT' suffix following the Tonawanda assembly date of November 10th, 1967 ?

The shots of the rear bellhousing flange area are taken standing behind the motor with top of pic being towards the front. Both the casting # 3916321 and 'HIPER' are turned around from the normal placement. The casting date is by the starter nose and is 'I_17_7' (17th Sept, 1967).

[Michael W.]

Re: Strange 427 casting numbers (early '68 321 block)

Ref. the 2BT suffix- usually a digit followed by two alpha characters is a marine installation, with the digit representing the year of manufacture. This might not make sense in this case with 2 being 1972 (?)

Dunno.