I,own a 1972 340 automatic challenger with original engine and transmission.The engine is a 340 and the transmission is the torqueflite.I,know that for this year the engine was detuned and pistons and valves wher changed,what I would like to know is if there is a kit that I can purchase to make my engine 1970-1971 specifications,thank you,[email protected]
Actually you have this in the wrong forum. You need to post this in the engine performance forum. You'll get more responses there.
I'll tell what little I know but I'm mostly a trans. guy. Yes they were detuned due to lower compression and lazier valve timing. From what I understand they lowered the compression by lowering the pistons in the bore so a piston swap will raise the compression back up to 70 specs. Your heads should have the 1.88 intake 1.60 exhaust valves. Depending on how much HP your looking to make you may want to have larger 2.02 inch intake valves installed also. The cam is probably also smaller. I know my 72 340 idled smooth as silk and I heard a stock 68 340 the had a noticeable rumpety idle and I read the specs on their cam so you may want to swap to the 70 cam also. Wheather you can get all this in a kit or not I don't know. I'm sure you can get it seperately. Maybe try Mancini Racing at www.manciniracing.com/ they have alot of stuff.
And after all this you'll probably need to recurve the distributor and possibly rejet the carb for max performance but those are minimal items.
