318/360 heads,with thumper cam

7duce swinger said

Darn,well the cam was installed by me and my brother in law,he said it was right on,(hes done tons of cams before)valve float?is that where both valves stay open,is that something that would happen at high rpm's?or is that just messed up timing,chain jumping a tooth?

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Valve float occurs at higher rpms where the valve springs are not strong enough to keep the lifter on the lobe after it goes over the nose, kinda like launching them off a jump. When the valves hang open longer then they should you lose power and if the stay open long enough for the piston to get high in the cylinder in relation to them they can touch. It's similar to the chain being off time but the engine will usually run fine at lower rpm's and at higher r's when the valves have to open & close so fast that the problem occurs. A replacement spring that matches your cam will fix the problem assuming that's what caused it.

P.S. your engine ran well before so i believe you had the cam and chain in ok.