I was wondering if anyone could tell me the difference in size of a 351C to a 428 and then to a 460. Right now my 70' cougar has the original 351C in it and it only has about 3 or 4 inches of clearence to the shock towers but I would like to drop a bigger block in it and was wondering how big of a block would fit? Is the 351C 428 and 460 all from the 385 serius block? If so would there be much difference in what will fit and what wont? Thanks for the help all.