small blocks or big blocks?
12-02-2009, 07:49 PM
#21
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Nice boats dave, Part for part I can't see where the big block parts are less expensive. If I was trying to build 600 to 800 hp I would agree but I am looking at maybe 500hp and I talked to a engine builder that will build marine 383's with warranties that produce 505hp at 6100 rpm and 495 ft# of torq at 4700 rpms with 750 cfm carbs for around $6200 each for long blocks with intakes, balancer, and pans. Thats what struck some of my intrest. I don't know if the bravo drives could handle that rpm range. As far as exhaust Lightning,Imco,Stainless, and Emi all make them for small blocks. All the new big blocks I have priced in that hp range were around $8000.00 plus. I am starting with no motors but have most of the parts to put big blocks back in the boat minus the long blocks. Like I said it most likely will be big blocks it's just something I have been thinking about.
Thanks for the compliments guys (bdarcher as well) I put a lot of TLC into the rides.
If the boat is setup for BBC then Id stick to a basic aluminum headed BBC- you'll be happier.
As was already stated - The thing is you can get used parts for BB's much easier SB- you can get the stuff- but its all going to be new.
Id bet that quoted HP number is through automotive headers though, not a marine manifold system. typically the dyno headers have SUPER LOOONG runners and are of course dry- a much easier prospect to make power than through a wet marine manifold.
Bravos will spin to 6K but the accessories don't like it too much.
Now that your on the board- well be "needing" some picts and regular updates so was can oogle your project.
Uncle Dave
12-02-2009, 07:51 PM
#22
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Big blocks, you'll never regret it, you may the small blocks tho if it is sluggish to plane or on top end. Much more potential in a big block too. The smalls will have to be worked already to get your goal.
12-02-2009, 08:02 PM
#23
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Power for power, the BB will make much more torque than the SB.
Eddie
12-02-2009, 11:03 PM
#25
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Just to throw this out, Small blocks weigh less. There was a killer 30" Chris Cat back in the early nineties that dominated with small blocks. Crimson Tide I think was the name.
It isn't to difficult to get 427 or 454 inches out of a small block. And I believe there are quite a few endurance components available as well as whipple huffers. It doesn't have to be a BBC to be marinized.
Just my $.02
.
It isn't to difficult to get 427 or 454 inches out of a small block. And I believe there are quite a few endurance components available as well as whipple huffers. It doesn't have to be a BBC to be marinized.
Just my $.02
.
12-03-2009, 12:06 AM
#26
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You are absolutely correct that you can build a big inch small block and save some weight. However, you will spend a bunch more money to do it instead of a mild 454 or 502. You will need some really good small block heads, exhaust, etc. It would be comparable to building a BB with Big Chief heads . To top it off a 454 ci small block will still not make as much torque as a 454 ci BB. The weight savings may offset the lower torque, who knows. But, it will cost more.
Eddie
Eddie
12-03-2009, 12:47 AM
#27
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Go Big or Go Home!
HP is for bench racing, torque in a boat at get on plane, cruise and top end gets it done! You can build a 496 cu inch 454 block engine inexpensively with aluminum heads and be pretty close to the weight of an iron headed small block. No inexpensive carburated 383 moderate compression pump gas engine is going to make the 600ft/lbs of torque the 496 cu-in. big block can make at less rpms and less loadings at cruise or at top speed. Price to buy the parts and build the comparable engines will be close anyway!
Go with the big block- "THERE AIN'T NO REPLACEMENT FOR DISPLACEMENT!" in a moderate rpm, pump gas, normally aspirated marine performance engine - PERIOD!!
end of Story!
Best Regards,
Ray @ Raylar
Go with the big block- "THERE AIN'T NO REPLACEMENT FOR DISPLACEMENT!" in a moderate rpm, pump gas, normally aspirated marine performance engine - PERIOD!!
end of Story!
Best Regards,
Ray @ Raylar
12-03-2009, 09:34 AM
#28
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Fixx
Have any of you toyed with a ls platform engine?????? ive seen a few that would whip the chit out of a 454 or a 496..
just my o2....
just a example of what you could expect out of a ls platform engine..I know this engine is pricy at 14 k but ???
http://videos.streetfire.net/video/G...ate_200738.htm
just my o2....
just a example of what you could expect out of a ls platform engine..I know this engine is pricy at 14 k but ???
http://videos.streetfire.net/video/G...ate_200738.htm
Last edited by FIXX; 12-03-2009 at 09:42 AM.
12-03-2009, 01:06 PM
#30
That boat would like to lose the weight that small blocks could save in the stern. As you unload a straight V at the stern they run better. I have had quite a few small block boats they are fun but can be expensive.
At one point we had two 13:1 372 CI dry sump 7200 RPM engines in a b boat. My experience with small blocks is that above 450 lb HP you save little on a cheap build. To go bigger you need bbc build cost anyway.
If it was mine and I wanted small blocks I would go 383 9.5 cr and keep it at 6000 rpm or less. To keep the cost low you need a flat tappet cam. No matter what you need a good oil pan above about 5400 RPM. The drive will take high rpm low torque all day.
If you keep the boat light you should be able to see 70 MPH
Steve
At one point we had two 13:1 372 CI dry sump 7200 RPM engines in a b boat. My experience with small blocks is that above 450 lb HP you save little on a cheap build. To go bigger you need bbc build cost anyway.
If it was mine and I wanted small blocks I would go 383 9.5 cr and keep it at 6000 rpm or less. To keep the cost low you need a flat tappet cam. No matter what you need a good oil pan above about 5400 RPM. The drive will take high rpm low torque all day.
If you keep the boat light you should be able to see 70 MPH
Steve
