stevesxm

dear dean,
your reputation and track record speak for themselves... and i am certainly not looking for anything for free... i was and remain technically curious even after all these years. if you are saying to me that you were and still are making 700 + at 9.5 , normally asprirated out of 500 in w/ a single 4 bbl , i say that is remarkable and ( pardon the pun) more power to you. seriously... that is magnificent work.

but for me it begs the question... you say above that your pleasure boat customers are still running these.... so that implies good reliabilty and driveability and reasonable hour life... so actually two questions please...

1) why is anybody bothering with hassle and expense of superchargers to get to the 700's and

2) how much do they cost ? ... because that is a hell of a package and they may be my next step because nothing i ever built myself or was associated with ever got even close to that. i needed 11 to 1 or better to make those kind of numbers and even that was hard and i can't say i ever got there repeatably

800XCR

I'd say they are mechanical roller engines that turn more than 5800 rpm's.

PatriYacht

Horsepower is a function of torque x rpm. Higher horsepower form the same cid size engine generally requires higher rpm. Drag race guys are getting a lot more than 700 hp out of 500ci, but they can rev to 7000rpm and more.

nordic95

Its a hydraulic roller cam in these particular engines.

Nordic95

stevesxm

sorry you feel that way. it is just it never occured to me that asking simple direct question was antagonistic... nor the observation that there was no simple direct answer.

also sorry that when you asked me to elaborate, you didn't like my opinion... note the word "opinion"

seems to me that if an individual is willing to publish a corrected sheet volunterily, then the uncorrected sheet w/ the correction factors can't be a state secret. but again... just my negative and antagonistic opinion.

mrhorsepower1

The engines I am referring to are 510 cu.in 9.5:1 comp, mech roller cams, wetsump w/ vac. pumps 1 X 4 carbs(dominator) and we had to use an iron head casting. Merlin head with extensive cyl.head development. The engines would produce 785 Horsepower @ 7200 rpm & we would run them between 6800-7200. The Great Lakes SilverCup Series used to have about 8-10 races per year that were about 80-100 mile races. We would race the entire schedule without pulling the engines until the Worlds. Change oil,filter,sparkplugs,Compression and leakdown test, and run spring pressures. The engines would look like new when they came in for a rebuild. The bearing were like the day they went in. In regards to your questions.
1) I don't know why.
2) For a pleasure boat application I would build a 510-557 cu.in. engine 1 X 4 to build the same power but keep RPM down. Most of my single carb stuff I still tell em' to turn the wick up = speed. The cost can vary depending on components. Somewhere between $26,000.00-$28,000.00
fully marinized with the best.
Best Regards,

Dean Gellner

articfriends

Mike,how much power will the motors lose with marine exhaust versus dry dyno headers? I have always heard you lose some of the positive scavenging effects of the heat building up in the header tube with a water cooled exhaust and even more once you mix water into the exhaust stream. If you made 630 "corrected" hp and motor loses 35-50 hp with a marine type exhaust,putting you lets say at 590hp,figure another 10-20 hp loss turning all the accessories (I see in the dyno pics you are not running any accessories) that would put you around 570-580 hp which,although it isn't as spectacular, is around what most guys are making with similar packages and very believable,Smitty

mike11

It totally depends on the exhaust, every one responds differently. Also Smitty there is more in these to be had, if we spent some time in the heads the 40-50 hp would be made up.

800XCR

Like I said, mechanical roller.

nordic95

Hey guys on this subject of dynoes and real uncorrected power,look at this article.I have been a Pontiac guru since 1987,building and running Pontiac motors in my 1968 Firebird at street nights at our local drag strips.Never would I have guessed that technology would bring one of these dinosaurs to this level on pump gas.And for the younger generations reading this,Yes Pontiac did manufacture there own engines before corporate world took over and started putting Chevy based engines in the Pontiac chassis.I think us OSOers should request the uncorreted power dyno sheet,there could be a 111% correction going on here not the claimed 1.11.
P.s. This artical just came in the mail today.
Nordic95