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I built a friend a 13:1 421" SBC and used PRO TOPLINE/RHS 235 aluminum heads with no porting. .690" lift cam.
At 2850# it runs 5.90s in 1/8.
You almost need offset rockers on intake valves with these heads, but with adjustable guide plates you can manage no offset if you accept a slight off center on the valve stem. No problems in 2 seasons.