My 518 C.I. 400 block pump gas stroker motor had 6.800 long rods with the 4.300 stroke crank shaft so it had a 1.58 rod ratio, the cam I used and liked a lot was a Comp Cams custom ground solid roller that had 260@.050 with .420 lobe lift on the intakes and 266 @.050 on the exhaust lobes with .409 lobe lift. It was ground on a 108 LSA and I installed it and tested it from 105 to 107, I also used a set of Haralnd Sharp 1.65 ratio rockers That motor with a set of CNC MCH ported RPM heads with a low deck six pack and 440 carbs. ran super well
That motor had 10.29 to 1 compression ratio with that set up, no quench at all
It liked to be shifted at the track at or above 7000 RPM to go as fast as the car would go, shifting it any lower would slow that rascal down