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Ok I know I don't have a chevy but I do like what I have. The boat runs fine and quick but stops at 5800. I think that it should wind higher after listening to everyone elses combinations.
The v-drive box has 12% gears and the prop is a 11.5x15 2 blade stellings.
The motor is a 440 Chrysler. 12:1 pistons, close chamber 915 heads, Offy tunnel ram w/600 holleys. The cam is a 268 @ .050 600 lift. Total timing is 34 degrees. I'm running 80% av gas and 92 octane.
The boat runs fine but would like to see about 75-85 out of it. I think thats easily achievable.
Where is the weak point?
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I haven't had the experience of v-drives just yet. My opinion goes only toward the motor side. I am assuming you already looked at the obvious such as the carbs opening fully and evenly and your tune-up is good. But I am a Chrysler fanatic.
Two things that come to the top of my head are, valve springs and the cylinder head. I think 6000 RPM's are pretty good for a stock unported 915's. They are one of the two best stock heads. Are the valves stock also? Tiny by todays standards 2.08/1.74. You could benefit from a bowl port and 2.14/1.81 valves. I have 915's with the larger valves and a bowl port, and an 850 in a jet. My 440 will rev easily to 6500. At this RPM you better be careful with oil. You need at least
a 1/2 pickup, or better yet, an external pickup like the Milodon setup and a huge pan.
I am guessing your valve springs are more likely the problem. With .600 lift it doesn't
take more than a hard season of boating to kill a set of springs.
Brian
[This message has been edited by wsuwrhr (edited July 09, 2002).]
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Originally posted by Kindsvater Flat:
Ok I know I don't have a chevy but I do like what I have. The boat runs fine and quick but stops at 5800. I think that it should wind higher after listening to everyone elses combinations.
The v-drive box has 12% gears and the prop is a 11.5x15 2 blade stellings.
The motor is a 440 Chrysler. 12:1 pistons, close chamber 915 heads, Offy tunnel ram w/600 holleys. The cam is a 268 @ .050 600 lift. Total timing is 34 degrees. I'm running 80% av gas and 92 octane.
The boat runs fine but would like to see about 75-85 out of it. I think thats easily achievable.
Where is the weak point?
I ran these numbers with that DYNO software and with the numbers you gave me, you make approx. 504hp @5500 RPM and 485lbs.Torque @5000 RPM.
I changed your carburetors on the induction section to a set of 750's and those are the numbers it gave me.
With some headwork and more air...period! You should be sitting fat.
Note- Impressive RPM's for a 440!
www.tpcracing.com (http://www.tpcracing.com)
Ty Lofstrom
tdlofstrom@tpcracing.com
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Originally posted by wsuwrhr:
I think 6000 RPM's are pretty good for a stock unported 915's. They are one of the two best stock heads.
[This message has been edited by wsuwrhr (edited July 09, 2002).]
Whats the other head?
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Yeah your right...I had my nose in this OLDS engine thinking...sorry about that.
The heads I choose on the program were pocket ported/polished. But still those numbers are impressive. I would say with some secondary jetting issues and timing the ignition correctly, you should get 6K+ real soon!
Thanks
Ty Lofstrom
www.tpcracing.com (http://www.tpcracing.com)
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The other casting is 906, these are a little more available. The 915's were a one year only on the 440 and they are harder to find.
Brian
[This message has been edited by wsuwrhr (edited July 10, 2002).]
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I just bought 2 more sets of the 915's for 150 a pair. He said they were prone for cracking and didn't want them. I had them checked for cracks before the purchase and they were fine. I think I will have one of those sets gutted w/bigger valves.
Thanks
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Damn, you stole them. I got mine off a 440 I pulled out of Pick A Part. $150 for the whole
motor.
That was pure luck.
Brian
