I think the cam is too big for your car and gears. That is probably why your cranking compression is a little low although there could be a lot of reasons for a low cranking compression.

My old 466 ran a 236 @ 050 solid flat tappet with ported RPM heads and cranking compression was 200 psi. That engine made 550 on the dyno and 475 rwhp. I tried bigger cams in that engine but they lost toque down low and didn't make up for it at the top end.

If it was my car I'd double check everything before pulling the engine apart, but if it all checks out I'd go about 10 degrees smaller on the cam and see what happens.

In the short term you can tweak the timing a little bit. Maybe add some jet, pull some timing out and stuff like that. Sounds like you have a wideband in the car so that helps to sort stuff out. Keep an eye on the plugs also.

Are you sure the intake port match is good? I had to build my own valley plate with batwing gasket holders to get the intake gaskets lined up properly with the 240 heads.