Reply With QuoteANYONE out there have OMC background that can give me a safe power level? I know the best answer is go to a V-Drive, but I like my odd-ball :idea: , just want to go a little bit faster!!!
I am going to date my equipment here, but what is the maximum power I can put through my OMC 800 drive?
I am currently running a moderate 350 Chevy, Edelbrock Performer RPM, Edelbrock Carter carb, mild RV type cam (unknown lift/duration ), and Osco cast iron risers with thru drive exhaust. I currently turn a 14 1/2 x 21+ stainless triblade up to about 5200-5400 rpm.
What I would like to do is swap in a new 280 Comp cam, and run exhaust extentions over transom off the Osco's (Now looks like I may have a set of Bassett O/T's coming, should help a little bit). My goal is to run out to 75 mph, which would require a 23+ prop, and about 5800-6000 rpm .
Will the changes I plan be enough and will the drive handle the power increase, or am I better off sticking with a proven 65 MPH sled???
ANYONE out there have OMC background that can give me a safe power level? I know the best answer is go to a V-Drive, but I like my odd-ball :idea: , just want to go a little bit faster!!!
I have no idea what that drive will handle, but I can tell you this; It will take much more than O/T headers and a cam change to do 75mph. A prepped 350 with a blower would likely get you low 70's w/ a Merc. drive. Don't know about the OMC? What is the ratio in that drive?
Much over 300HP will break that drive.
OMC 800 has 1.36:1 gearing, Maybe I'll have to be happy with 70 ish.
300 is about the limit for the drive? glad I didn't put the 400 pontiac in now.
Thanks to both
My friend had the very same boat you have. He made new mounts for the engine and raised it as far as he could in that hull with out using a sawsall. He fabbed up a nose cone for it and ran a 22" pitch 4 blade prop. He had a 355" SBC that was very stout. It pretty much could have went in the IMSA car that it was built for. I'm tellin ya it was one stout lil mouse. He wouldn't just mash the gas out of the hole and the drive held up. It would spin that 22" prop to around 7,500 rpm. lol Do the math, it was one runnin mofo.
I'm not an engine guy but be sure you don't put such a wild cam in it that it idles so high you can't get it in / out of gear with out breakin shit.
Thanks SuperDave,
I knew I couldn't just stomp it, but I like your math. With .25 prop slip that should have put him about 90, if the prop calculator I have is right
:2purples: .
The 280 cam I have should not be too radical, and will match the rest of the combo fairly well (at least until I talk the wife into new Vortec heads and Airgap intake). I know what I am doing over the next couple of weeks... Now I just need to get my O/T headers here
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Has anyone heard anything else from Bassett about there new mufflers????
In those 800 units is a splined shaft the is cheap junk. The spline is very fine and will shear very easy. I would be very easy on it. They are getting tuff to find parts for.
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