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Old 06-20-2005, 07:14 AM
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Default technical help pls.

hi

i would like to know if i change my 2x454/330hp carbs with bravo 1's to 6.2l 320hp's on 34foot speedboat would i loose on performance?

thanks
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Old 06-20-2005, 07:24 AM
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Default Re: technical help pls.

You should gain a small amount of speed due to the lighter weight of the 6.2 engines. Also the efficiency should go up slightly. You will lose some torque and may have to change props to make up for it.
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Old 06-20-2005, 07:57 AM
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Default Re: technical help pls.

I'd first compare torque specs on the 6.2 vs 7.4. You may lose weight, but may also lose any gains due to the lack of torque from the small block, you're pushing a good size boat. I'd step up to 454 mags or 502 if you want to stay with less expensive motors, if you've got the money, go to the 496's.... overall, my opinion is you have a lot of boat for a set of small blocks.... your going to have to make them work hard....
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Old 06-20-2005, 08:16 AM
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Default Re: technical help pls.

Originally Posted by East Coast B
I'd first compare torque specs on the 6.2 vs 7.4. You may lose weight, but may also lose any gains due to the lack of torque from the small block, you're pushing a good size boat. I'd step up to 454 mags or 502 if you want to stay with less expensive motors, if you've got the money, go to the 496's.... overall, my opinion is you have a lot of boat for a set of small blocks.... your going to have to make them work hard....

can i still find new 454mag's or 502's?
does anyone know how much they sell for?
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Old 06-20-2005, 09:07 AM
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Default Re: technical help pls.

Look here:
http://www.1800runsnew.com/newgm.htm
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Old 06-20-2005, 09:14 AM
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Default Re: technical help pls.

If your going to stay with big blocks.... go right for the 502, you'll be happy you did...... just a little more money and a little more spunk over the 454's... I'd go with the 502's, min 454 mags at 385 prop hp..... stay away from the base 454.... Good luck!!!
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Old 06-20-2005, 09:37 AM
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Default Re: technical help pls.

can i buy 2 base 502's from/ www.1800runsnew.com and complete them with the manifolds, carbs, etc.... of my 454's? by just bolting them on without modifications?
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Old 06-20-2005, 09:58 AM
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Default Re: technical help pls.

Sort of. There are differences between mark 4, gen 5, and gen 6 versions. What year are your present engines?
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Old 06-20-2005, 10:11 AM
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Default Re: technical help pls.

they are 1995 454/carbs
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Old 06-20-2005, 02:50 PM
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Default Re: technical help pls.

You likely have a gen 5 454 currently, I would contact the company you are going to buy from and tell them what you have and they can tell you what will or will not transfer over. They go through this everyday, I'm sure. There are some recent threads here at OSO on the subject and only thing I can remember something about the fuel pump I believe, give them a call and do some searching here....
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