Technical Chevy 1.6" valves in a flathead.

Not wanting to hijack further the other post on the subject, Supposing I want to fit 1.6 Chevy valves in my flathead, is it necessary to fit bigger inserts? Or are the valves not so far oversize that bigger seats would be needed?

Thanks in advance.

Mart.

 

I used them in my 218 cu in flat head Plymouth without any problems. Had to use the Chevy valve keepers.

 

No, Mart. The original seats are just fine. Just need to open them up a bit.
I have 1.75 valves in mine and the stock seats were ground, then the valve pockets opened up. Works great