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small blocks or big blocks?

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Old 12-01-2009 | 07:37 PM
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new to the site and I think its great. I started a new project its a 30 panther and I am completely restoring it. I am considering some 383 small blocks because of building costs and fuel consumption. I would like to see speeds in the mid to high 70's with bravo 1's. or should I just go with the big blocks? Do you think the small blocks would hold up? I have never owned a boat with small blocks but I like the weight and the hp and tq ratings using smaller carbs not to mention the room to work on them. What do you think? good or bad idea?
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Old 12-01-2009 | 08:32 PM
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BIG BLOCKS! No substitute for cubic inches. More tq at lower rpms. Probly burn the same fuel as a small block having to turn 8K to make the same HP and tq. Theres a reason why a million power boaters run big blocks and they keep getting bigger. I'm going from 468's to 540's this winter myself. The 468's are for sale if you go that way. Just my 2ct's.
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Old 12-01-2009 | 08:50 PM
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no replacement for displacement !!!!!! You want to save wieght and better fuel economy, go with some Ilmor's....probaly would take up alot more room though???
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Old 12-01-2009 | 09:17 PM
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Go with big blocks.

Its not because you cant get the power from a small block. You can but its harder.

Its that its actually more expensive to build small blocks when you are finished. Try to find a set of good used tune headers for a small block, or even a good manifold system.

SB parts (exhaust for example) are MUCH harder to come by and you need to be very carefull with reversion issues when camming up for bigger top end power.

You can take a whizz in the woods and find BBC marine parts.


Uncle Dave

Last edited by Uncle Dave; 12-16-2009 at 09:48 PM.
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Old 12-01-2009 | 09:38 PM
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I'm a long way from installing motors. It's been a few years since I have been around performance boats and I still think about those 27 cigs and magnums with the small blocks they were pretty cool and ran pretty good. The boat I am building won't even come close the performance of the new boats today so I am just trying to put together a nice clean and cool old ride. Thanks for the input and I most likely will go with some mild performance big blocks.
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Old 12-01-2009 | 11:50 PM
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383's whippled
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Old 12-02-2009 | 12:12 AM
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Originally Posted by osur866
383's whippled
540's whippled

or even better... 598's with 5.0 whipples... 1325hp on pump gas... under 6000rpm.

Chris
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Old 12-02-2009 | 07:27 AM
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Originally Posted by donnawanna
I would like to see speeds in the mid to high 70's with bravo 1's.
2 mild 454's built close to the standard bullet proof Merc 420, with Bravos should get you close to mid 70's. My Panther with a little warmed Merc 425's (compression bumped and a little bowl porting) would run 71-73 depending on conditions thru TRS's. You don't want to get to upside down on this project.
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Old 12-02-2009 | 08:04 AM
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Smallblocks have TQ
Attached Thumbnails small blocks or big blocks?-turbo-.jpg  
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Old 12-02-2009 | 08:41 AM
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Originally Posted by BDARCHER
Smallblocks have TQ
do those turbo's have water jackets around the turbine area. what kind of turbo are they?
thanks
Larry
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