I'll take your comments in order.
I like to make changes gradually. The rocker arm idea sounds good. I believe they come in different lift ratios so that might give me the need boost. Who makes them for a GMC?
A machine shop installed the Isky E2 cam 20 years ago. I assume they used the Isky instructions. The old Isky E3 cam has .298 cam lift, 286 deg. duration and 250 duration at .050. That might work? I don't mind doing additional engine work to make it faster as long as I don't loose too much in drivability. I plan to take the car apart this winter. I would like to drive it from San Diego to the Inliner convention in Colorado next summar.
I just found a calculation sheet from Arias Pistons which puts my compression at 8.77 The pistons have 27cc dome volume. The head has not been planed except for a slight cleanup surfacing, so I could take more off the head and raise the compression above 9:1. The head was done by Sissell and is a first class job. I think it would handle any reasonable cam grind. The HEI stays at 12 deg. up to 1300 rpm and then advances evenly up to 38 deg. at 3,600 rpm where it flattens out, with no vacuum advance connected. The engine never pings. The Sissell ported head improved performance quite a bit with times dropping from mid 16 to high 15 sec and speed going from the 85 to 89.
