Yontrop

I'm not quite sure on what an 'interference' engine is, exactly. Someone else on this forum oughta know.

EDIT: Oh, do you mean if the valves can be struck by the pistons? If the timing is off, I suppose so. The pistons in the truck are flathead, but I'm not sure how much room the chamber provides at top-dead center. It could be a possibility.

If you're replacing the cam, make sure it's perfect.

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I often tell people that I hate Fords with a passion... and I do. But honestly, I don't have a problem with them - they allow me to pay the bills, and keep myself fed!