429 newbie

Hi, I'm new here. I have a '73 Mustang and I'm thinking of possibly getting a 429 for it instead of rebuilding the stock 351C 2-v. I came across an ad for a rebuilt 429 Police Interceptor engine and rebuilt C-6 tranny combo. The ad said the engine has a D1VE block and DVEA2A heads. I tried to research the casting numbers...If I understand it correctly the head numbers in the ad are missing either a 2 or a 3 after the D. In either case the heads aren't from an interceptor engine and are the worst available for a performance build. Do I have this correct? Should I stay away from this engine? I won't be racing the car, but I don't want to scrap the Cleveland unless I can get around 450hp out of a 429. Also, how much more does a stock 429 weigh over a stock Cleveland?

My interest in this engine and tranny stems from them being already rebuilt with only a few thousand miles on them. The engine has a Stealth intake, Edelbrock 800 cfm carb and an aftermarket cam (not sure what kind yet). The C-6 is rebuilt with a 3500 stall converter. The combo costs much less than rebuilding my current 351C and FMX trans. Given my goal of 450hp in a car that won't be raced, should i stay away from this 429 just because of the poor heads? Could I swap out the current heads for a set of better stock 429 heads from an earlier year? What should I expect to pay for a set of C or DOVE heads?