Not to budge in where im not invited, but theres a few things that dont seems to add up here. First of all, why the 6pack? If your not planning to wind it past 6K, you probably wont ever use all 3 carbs at full cfm. 2nd, if you are running the stock dome and havent shaved the heads, you should be running 10.25:1 compression. Assuming it diddnt change sometime in 64. Finally, why the worry on the convertor? I may just be ignorant here(probably in fact), but it seems to me that a low stall convertor would be better for a light car so that your not lighting the tires due to revs. In case you diddnt notice, 64 riverias diddnt weight 2100 lbs

Oh, according to the book, there is .439 lift on the intake valve and .441 on the exhaust. Not much help without the rockers, but something to go by