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

Asked by Nov 08, 2014 at 02:10 PM

Question type: Car Customization

4 Answers


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.

1 of 1 people found this helpful.

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


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?


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.

Your Answer

Add photo

Related Questions

  • Should I modify my original 389? 18 answers

    I have a numbers matching 66 GTO; I have been thinking about boring 30 over, roller rockers, dish pistons, and a cam. Is this a mistake? Should I keep it original?

    1966 Pontiac GTO Coupe


    Car Customization

  • how should i go about getting more hp 36 answers

    i really do like the durability of my '01 dodge but it is in great need of some serious hp upgrades. i got the 5.9 liter gas guslling guttless wonder. its very sluggish off the line but not to to bad ...

    2001 Dodge Ram 1500 4 Dr SLT 4WD Quad Cab SB


    Car Customization

  • HP increase 27 answers

    civics hav a small amount of hp to begin with so if i already have a new exhaust and cold air intake what else can bump up the hp with out jumpin to a turbo.

    2000 Honda Civic Coupe EX


    Car Customization

  • More HP 5 answers

    I know its probably a dump pointless question but i have to ask. Is their any way, cheap way, to get a little more HP to my 2.3 4 cyl automatic. The 105 Hp with 135 ft lbs torque sucks

    1991 Ford Mustang LX Hatchback


    Car Customization


Search Car Customization Questions

Car Customization Experts

#1 Tom Demyan
Tom Demyan
Reputation 5,490
Reputation 3,460
#3 dandyoun
Reputation 3,300
View All

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.