Cars are all flat top piston ~9.6:1 compression. Two different cam flavors. The small 305 TBI cam in the civilian cars and the L98 350 TPI cam in the 9C1 cop cars. Trucks have 2 different piston options. 12cc dished for 9.3:1 and 18cc dished for 8.75:1. Most trucks are flat tappet.
Some of the G30 vans built as cutaway chassis in the mid 90s (with speed goverened TBI units) had roller cams and a different part number engine with a forged crank. Those were also setup with intake and exhaust rotators and larger valve stems to deal with the heat of burning propane or natural gas. They were setup with the GM industrial 350 cam. Peak torque was around 2,000 rpm on those. I have one and it had OEM piston oil squirting jets machined into the mains.
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