I never ever would run a flat tappet cam that late. The engine cant rpm enough to make up to that.
Even max ported those heads hit a wall near 6K.
Move the cams Intake Center Line to 105-106 at least. Looks like that engine doesnt like the wide centers of 112 LSA. IMO those wider LSA cams are more suited for engines with bigger heads, which are able to turn some RPM.
I dont like the cam...
You never did say what valve lash was hot, or at least i missed that part. If you have more dyno time, move the ICL to 105, and tighten lash up to .018-.020 Hot max. I will bet you anything, the motor will respond.
Those intake work, and are known to work for years, but in that particular combo, with a 4.25 stroke, it might not be the hot ticket.
If hood clearance isnt a issue, i would say you would see some return with a M1.
I dont like the Team G, the one I picked up suffered from real bad core shift.
That engine should be a easy 600-625 hp motor.
Change the cam all together. Go with a more conventional cam profile something with the LSA of 108-109. Dont be scared to add some duration to it.. The 112 suppose to broaden torque range...well with those heads, and that stroke..you just dont need it.. It will be a torque monster. You need to look in the other direction IMO...look for a cam with lobes that will help peak hp, and raise the RPM range to above 6K.