330 Hp to 400 HP
09-16-2011, 05:36 PM
#21
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I have to call BS on 547 hp with a peanut port heads! My 439 BBC was a max effort build, designed by Bob Mandera and built by Dave @ wesco racing and I'm at about 530 hp with AFR 265 oval heads, custom cam, custom carb and eickert headers.
I'm at a toss up to either do a mid build on my 330's or just sell them complete and find some nice 420's and refresh them.....
I'm at a toss up to either do a mid build on my 330's or just sell them complete and find some nice 420's and refresh them.....
Last edited by Vortecpro; 09-16-2011 at 05:40 PM.
09-16-2011, 05:54 PM
#22
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I've made 400+ hp with peanut ports multiple times. For a small cube engine that you only want to turn 5000rpm they're not a bad option, especially when they're already bolted on.. I agree with everyone else that said just drive it and spend your money on some different mills. If you do upgrade the cam's even to a decent flat tappet then you'll need to do springs too, while you're in there you'll want to replace the seals, then the stock rockers, then the 5/16 pushrods, then the..... It just keeps going. 
09-16-2011, 05:59 PM
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I don't know why everyone says 781s have such large cc chambers. If you look up the casting # on the Motech website it lists them at either 115 or 113. That's what I've found on every set I've ever ccd. I have four sets of 049s right now that all measure either 113 or 115.
I can't stand vortec heads. They have decent sized runners and small combustion chambers, but other than that, IMO they're junk if you want to have any sort of performance other than a stock 300hp ish towing motor.
I can't stand vortec heads. They have decent sized runners and small combustion chambers, but other than that, IMO they're junk if you want to have any sort of performance other than a stock 300hp ish towing motor.
09-16-2011, 06:05 PM
#24
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I've made 400+ hp with peanut ports multiple times. For a small cube engine that you only want to turn 5000rpm they're not a bad option, especially when they're already bolted on.. I agree with everyone else that said just drive it and spend your money on some different mills. If you do upgrade the cam's even to a decent flat tappet then you'll need to do springs too, while you're in there you'll want to replace the seals, then the stock rockers, then the 5/16 pushrods, then the..... It just keeps going.
In case people aren't aware, the Summit Racing house brand BBC cast iron heads are from Dart. They are cheaper then the Dart Iron Eagle's, but I don't know if that's because the 'house deal' or they have cheaper parts in them.
Back on topic, if doing anything with heads I'd find some that have a smaller combustion chamber
09-16-2011, 06:10 PM
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Whose exhaust system do you prefer on these ?
Do your run a crossover system or standard type Mercruiser ?
What size oil cooler do you install ? Preferred oil pan ? Stock 300hp one ?
If you don't mind sharing, do you have any pics of these installed in boats to see the above parts you use ?
Do your run a crossover system or standard type Mercruiser ?
What size oil cooler do you install ? Preferred oil pan ? Stock 300hp one ?
If you don't mind sharing, do you have any pics of these installed in boats to see the above parts you use ?
Last edited by SB; 09-16-2011 at 06:19 PM.
09-16-2011, 06:11 PM
#26
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computer got stuck sorry.
Last edited by SB; 09-16-2011 at 06:18 PM.
09-16-2011, 06:13 PM
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tripple post. sorry. Dang computer.
Last edited by SB; 09-16-2011 at 06:19 PM.
09-16-2011, 06:23 PM
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SB, these engines mentioned are are for automotive applications, I couldnt imagine the HP loss with marine exhaust. I test these engines on a SF 901 dyno with 2 inch full length headers into 3 inch exhaust. I know nothing about boats, but was searching forums and found this thread and felt compelled to stand by my dyno numbers, thanks for your interest. But to answer your question, dry 1 7/8 X 36 headers into a top ten shoot out 3 inch center in center out muffler.
Last edited by Vortecpro; 09-16-2011 at 06:26 PM.
09-16-2011, 06:37 PM
#29
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SB, these engines mentioned are are for automotive applications, I couldnt imagine the HP loss with marine exhaust.
I test these engines on a SF 901 dyno with 2 inch full length headers into 3 inch exhaust.
I know nothing about boats, but was searching forums and found this thread and felt compelled to stand by my dyno numbers, thanks for your interest.
I test these engines on a SF 901 dyno with 2 inch full length headers into 3 inch exhaust.
I know nothing about boats, but was searching forums and found this thread and felt compelled to stand by my dyno numbers, thanks for your interest.
Was wondering how you'd make those engines you mention survive. Just couldn't see it happening.
The performance boating I/O world can be and usually is very different. Valvetrain, camshafts, rotating assemblies, oiling, of course exhaust and a lot of times heads, intake, and carbs.
Stock low hp motors, not many differences.
Last edited by SB; 09-16-2011 at 08:47 PM. Reason: few spelling mistakes
09-16-2011, 06:46 PM
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Okay, thanks for that info.
Was wondering how you'd make those engines you mention survive. Just couldn't see it happening.
The performance boating I/O world can be and usually is very different. Valvetrain, camshafts, reciprocating assemblies, oiling, of course exhaust and a lot of times heads, intake, and carbs.
Stock low hp motors, not many differences.
Was wondering how you'd make those engines you mention survive. Just couldn't see it happening.
The performance boating I/O world can be and usually is very different. Valvetrain, camshafts, reciprocating assemblies, oiling, of course exhaust and a lot of times heads, intake, and carbs.
Stock low hp motors, not many differences.
