I have a chance to buy a 1981 f150 steo side with the 351m in it the guy tells me he knows it has a holley 670cfm carb with spacer, msd ignition system, c-6 tranny with shift kit, ford 9inch rear end, duel exhaust with two glass packs and headers. He believes it has a mild cam as well. I asked him who did the work and he said it was his friends but he has died since. So how would I know it has a cam in it? also what kinda power am I looking at here est.?

 

A lopey idle would be a sign of a cam being installed.

Power cannot be estimated unless you know what cams and pistons are installed, what heads and intake manifold are on it, and what your compression ratio is.

If it is an otherwise stock engine with just a carb swap and a cam, you would still need the cam grind information.

It is possible to measure the camshaft without un-installing it, but you would need to pull a valve cover and use a dial indicator with a magnetic base-mount and you would probably need a degree wheel to note your measurements.

In all honesty, I wouldn't worry about the cam being upgraded or not. I would drive it and check the compression, make sure it doesn't smoke, and buy it if I liked it. A cam is something that can always be changed out later if need be.