Being I didn't build my engine, I have a similar situation, smaller chamber (I'm suspecting early semi closed chamber 273 on right side) but haven't checked casting number yet. 145 PSI cranking pressure right bank and 135 PSI cranking left bank, with the intake closing 107 degrees after BDC. Either that or the right head or deck had a pretty serious cut taken from it. I tell myself that the flow restriction of the semi enclosed chamber evens the power out the output of those higher compression (10.4:1) cylinders to that of the lower compression (9.9:1) cylinders.:rolleyes:
