SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: Ultra460 on February 27, 2009, 07:14:07 PM

Title: Need some carb jetting help?
Post by: Ultra460 on February 27, 2009, 07:14:07 PM

It's a 330hp 460. Mostly stock with a weiand stealth intake manifold, holley 850dp carb, mallory unilite distributor, long bolt logs.

That's about it.

The carb currently has

-choke horn milled off
-80's primary and secondary
-25cc primary acc. pump cam
-50cc secondary acc. pump cam
-65 powervalve


What do you think I should be running for jets?
Also should I bypass the power valve or leave it?

Thanks, John
Title: Re: Need some carb jetting help?
Post by: BOOST on February 27, 2009, 07:21:17 PM
 80's seem a little big for that set up,start off with 72 front 78 in the rear.
Title: Re: Need some carb jetting help?
Post by: Ultra460 on February 27, 2009, 07:24:21 PM
80's seem a little big for that set up,start off with 72 front 78 in the rear.


Yeah I know thats what it came with. Carb is definately over kill but I had plans to grow into it... ;D

So should I keep the PV?



By the way I'll give you a call tomorrow.
Title: Re: Need some carb jetting help?
Post by: BOOST on February 27, 2009, 07:31:33 PM

Yeah I know thats what it came with. Carb is definately over kill but I had plans to grow into it... ;D

So should I keep the PV?



By the way I'll give you a call tomorrow.
Keep the PV in the front and ditch the one in the rear.
Title: Re: Need some carb jetting help?
Post by: dm2bfree on March 11, 2009, 06:00:58 PM
I have the same question for my boat, which jetting to start at??

460 ford, 425+ HP, victor JR manifold, MSD dizzy & Mallory Hyfire 6 Ignition..

I just ditched my Holly 750 vac carb for a Holly 850 mechanical..

This is the carb I'm putting on it.. http://www.socaljetboats.com/index.php?topic=5797.0
Title: Re: Need some carb jetting help?
Post by: BOOST on March 11, 2009, 06:08:29 PM
Do you know the setup on the carb? what size jets, power valve ,air bleeds,give use more info.
Title: Re: Need some carb jetting help?
Post by: dm2bfree on March 11, 2009, 09:15:56 PM
It's has the choke horn milled off..

- 80 Pri,  82 Sec

- 65 power valve (in both pri & secondary, only the secondary is stamped w/ the 65)??

- It does have air bleeds (they don't appear to be drilled larger than stock) and their not adjustable..

- The primary accelerator pump cam is light green/clear w/ 218 stamped on it..

- The secondary accelerator pump cam is white/clear w/ 466 stamped on it.. Not sure which one for sure though cause on Holley's site the orange has the same 466..    http://www.holley.com/20-12.asp


Am I missing anything?? Sorry, I'm not the best w/ Carbs,  but I'm pretty mechanical and can learn..  I can read plugs and adjust OK, but I'm not the best at dialing a carb in.. Anyone know of any good books or knowledge of the in's-n-out's of tuning a carb?

-- Also, i've from reading above it doesn't seem like the secondary PV is needed?? If so, how is it removed?  I know I can just unscrew it, but do i just leave the hole there or cover it up?

Thanks Guys!  ;D

Title: Re: Need some carb jetting help?
Post by: BOOST on March 11, 2009, 09:19:00 PM
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