If you have put 2.19/1.88 or even 2.25/1.88 valves in a 396/402, have you had any problems with the smaller bore interfering with the larger valves?

if i remember right the bores have a relief cut in them when they used the big valves (L-78) if you have a 325 or 350hp motor these reliefs must be added for 219s

If 2.25's do fit with the stock bore, the flow will be terrible. My head GMPP heads have the 2.25/1.88 combo. With the 4.280 bore, the 2.25" intake is close to the cylinder.

I ran 2.19/1.88 valves in my 408 but I opened the chamber walls up to unshroud the valves a little. But I had no clearance problems in the cylinder

The original 350hp block is gone. The current block is a later model block with the relief already cut in the cylinder. Yea I know why did it get replaced with another 396? This happened years ago when it was still just a street car. What I want and need is a 454 block, even if I just put my crank and everything over in it and build a 427. But it has been fun getting my little 396 running as good as it seems to be running.