need a good combination

Hello guys i just bought an old 5000 70 t-bird with a 360/480 429 in it and im having problems with it , it just seems really weak on the bottom end it has a holley 750 dp mech secondary carb on a performer 460 intake, msd ignition, the stock dove c heads. The only reason i bought it was because growing up my dad had one an it would run like a bat outta hell for a bone stock 5000lb car it had alot of torque an would burn the tires off an ive had blower fox bodys and 351 69 fastbacks, cleveland torinos but that car always stuck out in my mind it was what made me a ford guy i guess. What im getting at is i cant seem to figure out why this car is so weak ive been told it could be the timming set may have been changed to a post 72 retarding the cam,the cam itself worn, the dp holley, and even a bad torque converter causing this lack of power . Ima start with a compession test an then the timming set if comp checks ok if i rebuid this back stock with mild head work what would be a good cam to go with spec wise for the low end an to get it moving an give it some grunt. i was looking at a 1400-5600 rpm range 4by 4 cam 262/270-218/226 @ 50 -514/524 lift any ideas on a good cam or what could be the problem thanks for any help ps. If i cant resolve this issue i may stroke it an add some scj heads to prove a point to my chevy friend whos givin me grief about 429s.

In my opinion, that camshaft is to big for your application; especially in a 429 with a 4,000+ pound vehicle.