First off, hello all, new here...   Have a 76 Tahiti Tiger, 455 Olds bored to 468, balanced, Torker intake, Rewarder Twisties, Flamethrower HEI, Milodon big pan, Hydraulic Comp Cam 280dur/.490 lift

Currently the boat has a Holley 4175 Spreadbore 650CFM carb.  It is leaking, yes shockingly so.     It did however run great with this setup minus the Rewarders, it had logs.  Would turn 5200 rpm with A impeller Berk GPS'd at 64mph. 

So now with the Rewarders I am wondering what carb to get.  I am thinking somewhere through 750 - 850 CFM Holley or Demon. 


Whaddayall think? 

Mighty Marine Demon  me like 
http://www.barrygrant.com/demon/default.aspx?page=21a

According to what they are saying it seems I should pick a 825 or 850.  What diff will the Annular Boosters give me?  Any loss of bottom end with either choice? 

Looking for all around performance, still a decent idle, good out of the hole for skiing, and decent top speed.  Also planning on getting a diverter at some point...finally!

THANKS!

Mark

BTW also should take into consideration how the boat would be driven, (like a rental, or like it belongs to someone bigger than you )

The one good thing about a jet is acceleration is based on water velocity, not engine RPM (so the engine gets into its powerband without a huge load).

Hope this is helpful.

Headers will flow better than logs everytime but I don't believe it will make an enormous difference, that being said, they could cause a leaner burn do to the exhaust gasses being more efficiently evacuated.

You should get better throttle response, a little more RPM, but the "Assanometer" won't see a lot of difference, but they do look cool!

You would see more gain with a tight pump.

Ordered a Proform 750 Race Series, should be here today. 

Went with a 750 because I don't think my engine needs an 850 with my setup.  I don't plan to run it past 5000 rpm either, cause I don't want another blown bottom end!  Hopefully be on the water testing this weekend.

I am running a Holley 4150 750 DP on a 468 olds 10:1, comp 280H cam, pocket ported G heads, comp magnum roller rockers, glenwood logs in an 18 ft Kona.  Engine turns 4850 with an A2 in a Berkley 12 JC @ ~ 61.5 mph.  I am still playing with jet sizes, but so far the 750 is doing a great job.

cool, I have the same cam, but stock K heads and and stock rockers.   

I think that you will be happy with the carb choice