74SD Formula is correct. Most stock Pontiac heads had 30 degree intake seats. The exhaust are 45 degrees.
IIRC, the SDs, and maybe maybe a few other oddballs, had 45 degree intakes.
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'66 GTO convertible. 462, KRE 290 cfm Dports, SD "Old Faithful" hydraulic roller, CVM ported aluminum Tripower, TKO600, Moser 12 bolt
"I open up three deuces, I'm Never Coming Back!"
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