Two holley 94 little fat

[rooster57]

Hello fellas
I purchased one of those twin 3 bolt adapters for my Chevrolet
305. They have the stock power valves 7.5 I think and jets are 51
It's a bit rich at start up and loads a bit at the light
But it runs good. Speedway says their stromberg knockoffs are 6.5 pv and 45 on the jets
My vacuum is 18 or so at idle
So what do you think I should run for a power valve and jets ?
I am thinking 5.5 on the pv and 49 on the jets !!
I came to this conclusion with the rock paper sizzors method.
These are original 94s

 

[rooster57]

To clarify I only purchased the adapter the carbs were from an old guy north of town who had these in a box I. His attic. I put kits in them from autozone.

 

[sstock]

Recommend welding a bung in the exhaust down pipe and buying a wideband then start from there, otherwise you are shooting from the hip.

 

[railroad]

If you are rich at idle, make sure your fuel pressure is not an issue, then I would back down a couple of jet sizes. 7.5 's might be alright. I would not change jets and p v at the same time. The newer style power valves do not clear on the spring side in the carb. You can get the right ones from some of the 94 sites or dremel some clearance inside the well. Throw a vacuum gauge on the windshield. You can change jets until you get it running clean above the p v rating, then change p v's to finish up.
good luck,

 

[2old2fast]

Not knowing much about "94's" I may be way off here , but why does changing main jets or PV's have any affect on idle mixture ?? Just askin' ....
dave

 

[rooster57]

Thanks RR
It looks like when two carbs are used the power valves can open and let to much fuel in at low vacuum
And the big jets add to the rich factor. Some guys just purchase the pV block off plugs . Charlie at vintage speed uses a primary and a secondary set up and he blocks the rear carp PV . and that makes sense with out progressive linkage. The edelbrock and speedway versions are also quite different . Vic uses a primary and secondary carb . But I don't like the progressive linkage . These carbs are about 175-190 Cfm each. Speedways setup is like mine but with small jets 45 and a .65 pv.
So I'm still fishing . The only other guy on here is dons rods who runs this setup. I would like to know his specs!!
For jets and PV.
I am thinking that a 5.5 on the pv and 48 are going to be a winner.
Once you are off idle it runs like a striped ass ape.

 

[railroad]

If idle is your only issue, I would look into the carbs at idle. It sounds like the venturi's may be dripping. This is either fuel pressure, assuming the needle and seat are OK, or the power valve is not sealed or closed. The gaskets on the p v need to be specific. Make sure they are seated on both sides, the pv and the carb. I am going to mention this just in case, I am sure you have the idle jets adjusted?

20ld2fast, you are correct, main jets and proper working pv should not affect idle.

 

[rooster57]

Thanks I've got two new pv coming
I read several guys say the new rebuild kits pv may or may not deal properly so I ordered done 5.5 and 49

 

[rooster57]

Yes RR I purchased a new holley regulator
To try and maintain 2-3 psi of fuel psi .
The pV are the ones that came in the kit and are not stamped so I am suspect they are the culprit I hope .

 

[Screaming Metal]

See what ya got at idle when you get your PV's in and small down your jets, set your idle mix. screws so your idling off the front carb, and see how that does.
If the idle is good when you change things, go that route, every motor is different. Idle is usually a dedicated circuit, apart from the mains and PVs....
A vacuum gauge, and a good ear, you can pretty well set most things....94's are really sensitive to float levels and fuel pressures. I'm with you, I'd try 48s or 49's....rememeber....you got that doublepumper effect going with both them dumping at one time.

 

[railroad]

Not that you have, but I have read that the 94's are unmanageable with the choke blade removed. Just read it, not experienced it. Next thing, I think a source of information is Flat Head Jacks. I think that is where I bought my power valves, cheaper than Summit and the right ones.