I have a '73 Mustang. I'm thinking of putting a 429 in it instead of rebuilding the stock 351C 2-v. I found an ad for a rebuilt police interceptor 429/rebuilt C-6 combo. The ad says the block is a D1VE and the heads are DVEA2A. I've tried to research casting numbers...If I have it right the head #'s are missing either a 2 or a 3 after the D. If I have it right these are the worst heads for a performance rebuild and aren't interceptor heads. Am I correct? Should I stay away from this engine? I dont race, but I dont want to swap out the Cleveland umless I can get 450hp or so out of a 429. Also, what is the weight difference between a stock 429 and a stock Cleveland?