On a stovebolt cam timing is simply a matter of aligning a couple of dots center punched on the crankshaft and camshaft gears. It's not idiot-proof, but somebody would have to be pretty incompetent to mess it up. A 235 has some flat spots milled into the camshaft for clearance between the connecting rods and the cam, but there would be lots of other symptoms including probably not running at all, if the cam was far enough out of time for the rods to hit it. It's a huge job to check the cam timing, involving removing the balancer and the timing cover and checking the mesh of the timing gears. There's a way to check cam timing by watching the action of the rocker arms in relation to the timing marks on the flywheel, but that would require writing several paragraphs of detailed instructions. Let's hope you can discover a simpler problem before jumping into major surgery!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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