Quote Originally Posted by jerry clayton View Post
vacume line is on the correct port for the ford dist. unhook and plug the line when setting the timing- for a 1971 4* btc is listed, 10* for most other years---starting around mid 70s they retarted the camshaft 8* and advancing it back up will help--when they lowered the compression and did all the smog stuff the econ went to hell but advancing the cam, more timing and possibly going to 68 - 70 jets in the primaries will help performance---It isn't a 4 wheel drive is it???

I do agree with the later '70s retarded camshaft in early 460's. It does entail a front of the engine tear down and a new pair of timing gears and new chain - which if it has over 50K miles, probably needs anyhow as the OEM's are 'silent nylon'. From doing that mod to a '76 F250 and a '79 F350, I can assure you that it does make a difference in gas mileage and even better, performance. Set the timing then at 9-10 deg BTDC. Also, trash that bitty 475/525 cfm OEM carb for something that has some venturi area so it can breathe a bit better - the mid to late '70's heads aren't the best