Hi I have a 65 GTO with a 389 tri power 360 HP would like to rebuild and end up with 500 to 600 HP how should I go about this ie. parts

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James answered 2 years ago

Wow 500 or 600 hp from a 389. Pay attention to details like port & polish the heads or buy aluimium Eldelbrock or Dart racing heads, w/ big valves, hi-lift & long duration racing cam & kit, high compression forged pistons, MSD ignition, get a engine shop to balance the whole assembly, & assemble the short block, add a racing oil pump & pan, high flow water pump, & top it off with a big port aluminum high rise intake manifold & & a big Holley 4bbl carb like 900 CFM's (more than your stock tri-power.

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1bad_goat answered 2 years ago

Thanks for the help would like to keep the tri power setup if possible,

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James answered 2 years ago

Your tri power doesn't flow enough CFM's to make 500 or 600 hp.! It looks cool that's about it. The 1965 intake is old " low rise" tech & new after market Eldelbrock or Dart hi-perf head intake ports are much bigger too. So a new hi-rise aluminum intake manifold needed to match. If you >have to< keep the 3 / 2's dump the Rodchester carbs for bigger 3ea. Holley 500 cfm 2bbl.= 1500 CFM's see?

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James answered 2 years ago

Just a thought, you can mix & match some 421" motor (cyl heads?)stuff too, they're compatible. If it were me I'd just build a ground pounding 455. The newer 400-455's are a much better design. I had many friends with GTO's but they never beat my '69 big block 396 then to a 427 L-88 SS Camaro.