hi iam doing the same. a 5.2 magnum in a 69 valiant 100 2dr post. my engine had good cylinders and pistons also. the crank was hurt tho. lack of maintance. the heads were cracked also. iam going to use a hughs cam (whiplash) there springs and retainers along with there roller rockers. i ditched the efi and went with an airgap intake. not sure about the carb yet. you can use the la 360 pan and timeing cover. i wanted to use the stock fuel pump. i know it wont be 400hp, but if it came close to 275 i would be happy. for the tranny i built a 904 lock-up with a factory high stall and the low ratio gearset. all that with a 2.76 rear gear should be a good all around crusier.