If I remember correctly, the booster is approx. 7 1/2" diameter, I can double check it tomorrow and update if significantly different. I've got both style setups on the shelf (okay, in boxes in the loft...) and the bracketry looked pretty much identical between the two- again, I'll compare them a little closer tomorrow. I've also got the original '66 "ten bolt" booster setup stashed somewhere up there too- if I can find it, it would be interesting to see how much the brackets differed, if at all, on that setup compared to the two later setups.
FWIW- there was also a booster with a 6 1/2" housing on it that was used to clear the engine on the '67-'69 big block A bodies. I would imagine the bracketry was the same for these, as I can't imagine the factory would tool up any more different parts than necessary. Never had my hands on one of these, though; so I can't say for sure.
