Carb guys who really know Holleys-..help

[Danny Mc]

I have repaired lots of Holley carbs but this one has me puzzled.
Carb is Holley 4bbl 4160 650CFM list #50399, JL-9510 FB, Ford tag-E6JLFB...A 6E15.
Holley said it's a marine carb proprietary to Ford, (but don't know a lot bout it) they suggested Kit 703-28, carb has #73 jets pri and best they could figure the sec plate is equivalent to#79 jet, 6.5 Power valve.
Now to the Question.
I am building it for 4.3 Vortec eng with Edelbrock 2114 intake, cam from 96 S10, Heads from 2001 eng., 93 Mercruiser ign. I want to replace the Weber. I am wondering if the jet sizes are close enough to be safe, ie not too lean. I hope someone here has worked on one of these and are aware of what else i should do on assembly. Thanks D Mc

 

[EddiePetty]

Re: Carb guys who really know Holleys-..help

.......based upon my racing days (daze), with that current power valve you should be dumping plenty of fuel with the current jets, though I personally would perfer a power valve in the 3.0-2.5 range and jetting in the upper sixties to begin with.
The true test will be timing, temperatures and a careful reading of the plugs. See if you can make the initial run with straight gasoline as ethonol can really mess up plug readings.

See if this helps ya'.
http://www.holley.com/TechService/Library.asp

 

[chaparall villain 2]

Re: Carb guys who really know Holleys-..help

was this the carb original to the 4.3 that was in the boat ... i am running 74 and 79 jets on a 750 holley on a 383 in my boat and it fairs well but like was already stated in the post i would definitly do some runs with it on low and high circuit and check the plugs to see what they look like should be brown in color ... not blk or white and i would say start with the combo your talking about and if its too rich on low or high side adjust accordingly .... better a little rich than a little lean ... boats tend to need at least a number jet 4 higher than in an automotive application because they are always under strain ... good luck

 

[Danny Mc]

Re: Carb guys who really know Holleys-..help

The original Weber carb was on a 93 non vortec eng. When I went to the vortec had to buy the 2114 intake, using the Weber now with adapter plate. I see in posts that most guys are some where around #73 jets with this combo. Hoping the Holley would be close for starters. This eng is in 93 Regal Volante 206SC, 23P SS prop.

 

[jtmarten]

Re: Carb guys who really know Holleys-..help

Run it WOT, shut down, pull and read plugs, adjust jets to get proper color.
How much vacuum do you have at idle? If you don't know, you don't know which PV to install.
I've seen other posts about Holleys with 70 mains and running very lean on a 4.3 vortec. The 73s should be a good starting point.

 

[Aloysius]

Re: Carb guys who really know Holleys-..help

The "Weber" is probably a quadrajet..a spreadbore carb. You really don't want to put a squarebore carb on a spreadbore manifold.

WHY do you want to replace the "Weber/quadrajet?

 

[Aloysius]

Re: Carb guys who really know Holleys-..help

Just remembered most "Mercruiser" Webers are really the old AFB, now marketed by edelbrock, as opposed the Rochester quadrajet that was also marketed by Weber.

AFB/Edelbrocks use an air valve secondary, like a quadrajet, but ARE square bore, probably with an adapter plate. Adapter plates are detrimental to performance. If you have a spread bore manifold, a quadrajet would be the preferred carb..unfortunately, they have little tuning capability, other than power piston springs, a few metering rods, and the all important air valve adjustment.

 

[Borchik]

Re: Carb guys who really know Holleys-..help

that carb was used on OMC 5.8 fords, mid 90's if i remember correctly

 

[Aloysius]

Re: Carb guys who really know Holleys-..help

The big variable on Holleys is the power valve. A 6.5 power valve opens at 6.5 inches of vacuum, which is about cruise on many marine engines. This opening increases the effective main jetting by 4-8 jet sizes, depending on the metering plate orifices.

Most carbs are factory jetted pretty close for all practical purposes. If you have to change the jetting more than a few jet sizes, you've got the wrong carb for your application. It's highly unlikely a "marine" carb would ever be too lean!

 

[Danny Mc]

Re: Carb guys who really know Holleys-..help

I have the adapter because the 2114 Edel. manifold is square bore and weber is spread bore. When I install the carb I will adjust idle with a vacumn gauge, then check under acceleration to verify what diff PV is needed, if any. I've been working on Holleys for 40yrs, just never had one the Holley tech knew nothing about.

 

[Aloysius]

Re: Carb guys who really know Holleys-..help

Here's what stumps me, Danny. The "Weber" Edelbrock is a square-bore carb..the "Weber" quadrajet is a spreadbore.

Personally, I'd stick with a squarebore Edelbrock carb rather than a Holley. Sure, Holleys are tunable, but so are Edelbrocks. the Edelbrocks leak alot less!

I've been working on Holleys for 40 years too. I rebuild carbs for beer money, and I can assure you holley has bought me alot more beer that the venerable AFB Edelbrock!

 

[Danny Mc]

Re: Carb guys who really know Holleys-..help

I am using this carb because it's what I have. Carb is for my sons boat that I just built a new eng for and the Weber is being a pain in the azz, don't want to spend any more on it. It leaks fuel when stopped and very hard to start (i know bout momentey switch to pump), boat won't hold plane cause fuel air ratio is not right. I know I could tune it but NOT going to, don't like having the adapter plate either, want to put square carb on square intake.