My brother used them on his 306 for 8 years after he ported/polished and installed larger valves in them. He made 311 rear wheel horsepower and 287 rwt and ran consistent 12.50's @ 108-109 mph in the quarter mile. This combo was mated to a T-5 and 4.30 gears. Good luck with them!
No. i bought them already ported but with a g force t5 and 373s the car goes 12.0s all motor, and 11.18 on the sauce. I just bought a set of trick flow heads so if you know anyone who is in the market let me know. . . the port work done on the heads is top notch! I would take 350 for them....bought them for 450
1982 I used a set of ported C9OE heads on my 306. with a very mild hydraulic cam and 1 5/8" black jack headers,holley 600, ported C5 4bbl iron manifold. I made 360fwhp.
As far as times wih thoise heads on 302's im not sure but i have driven a 85 with 302 heads with 351w heads and the thing was strong. Was an amazing engine.