HOM MUCH HP I AM RUNNING AFTER UPGRADES.

STOCK 91 454/B1 MERCRUISER 330 HP

ADDED 502 ALUMINUM HEADS
ROLLER ROCKERS
502/502 CAM
750 HOLLEY
MARINE POWER MANIFOLDS
502 INTAKE
10:1 COMP I THINK

MY GUESS IS 450HP TO 475HP

ALL INPUT IS WELCOME

Don't have a clue but it sure looks nice

Anyone Have A Hp Guess?

Well you opened up the breathing but the pistons are still 454 right? I would say more like 420, a 100hp increase would be huge and an HP 500 has about 474hp, which you are close to except for the holes being 454 still. To bolt on 100hp would mean a charger of some sort, either super or whipple or No2. There should be a formula but I don't know it. If I am wrong let me know but I had a magnum 454 and those are like 365, I also had 502s built to HP500 specs and saw 480hp. Let us know if you dyno it or if you realy know.

I CAN ONLY GUESS SINCE I WILL NOT DYNO THE MOTOR. I WILL POST SOME SPEED GAINS AFTER THIS WEEKEND WHEN I DIAL HER IN. I DO KNOW WHEN I FIRED HER UP LAST NITE I WOKE A FEW PEOPLE UP AND HAD THE COPS CALLED ON ME. I GUESS I REALLY SHOULD NOT CRANK HER UP 11:30PM BUT THATS WHEN I FINISHED AND THE KID IN ME WANTED TO HEAR THE RUMBLE.

STOCK SET UP WITH A 23P MIRAGE WAS 59.9 GPS, 30 GALLONS OF FUEL AND 2 200LBS GUYS.