Opinions on this Custom Comp roller cam, engine combo

Playing with the ex duration on a build like that is really more like fine tuning.
Don’t worry about it.
Besides, the Stealth exhaust ports aren’t fantastic.

I’d use 1-7/8” or 2” headers.

Properly recutting the seats and blending the bowls on Stealth heads gets them into the 280 range.

1.6 rockers will likely require modifying the intake pushrod tunnels.