Big Block Question

[YENKO DEUCE REGISTRY]

Sounds like a rallye green '69, v/t, 3moldings, buckets, no console, deluxe interior, etc... from Maryland! This topic/car has been discussed at length here on another post. Can somebody post a link?

As for your two specific questions. The heater core itself does not indicate BB or SB, you simply install it in the opposite direction for a BB. The heater box cover is also the same except for the two holes in the middle (which can be drilled, or avail repro). The 3/8 line was also a common switch back in the day when somebody souped their engine up. So, neither of these two items can be relied upon to determine BB vs. SB. If the trans crossmember is still there, check the trans mount opening. BB and SB's had different openings.

M