72' CL350 valves v.s. pistons :c

[_Atom]

I picked up a basket case 1972 cl350 project a while back and went through the engine top to bottom. The original pistons were seized up and the cylinders were rust pitted, so I had it bored out by 0.5mm and installed some over-sized Wiseco pistons. I also sourced out another 350 head because the valves on the original were rusted solid into the guides.

Everything seemed good so I started putting the top end back together -

Did the cam timing - turned it over with the flywheel a few times, seems good
Gapped the rocker arms - still turns over smooth
Went to check the points gap - all of a sudden... piston contacts the exhaust valve ??? wtf?

So I have three theories:
1. I'm an idiot and gapped the rockers at the wrong point in the cycle
2. The head might have been listed wrong on ebay and been from a different year cl350 (but I'm not sure if that would even matter??)
3. Over-sized Wiseco pistons are incompatible with the stock cam shaft?

I hope I'm just an idiot, but If anyone has some insight about the different head years or the over-sized pistons it would be greatly appreciated.

 

[goldy]

Make sure the exhaust valve is not sticking in the guide. Did you remember to tighten the cam chain adjuster lock bolt?...this can cause the cam chain to slip out of time. Check your cam timing and re-do the valve clearances. Gotta be something simple, best of luck!