Six Pack carb parts

Has anyone installed the ProMax metering plates in their outboard carbs? Do they work good? What size jets do you use? Are they supposed to be the same size as the orifices in stock metering plates? I bought these for mine but had second thoughts about using them. I was concerned that mine had been modified and thought the ProMax might help get the carbs back to square one.

Nothing wrong with those metering plates, I've put them in carbs at customers request and they run great. However, you certainly don't need them to make your carbs run right, and especially not to get them back to "Square One" (stock). There looks to be a jetting guide on the paper underneath them in your pic. If that doesn't answer your questions you should probably call Pro-Max.

I have used them ,, worked well for me. if you find that you need to adjust the fuel rate , it is nice to have a quick and easy way to do it. I used a dyno run to get mine right . 1 time and it was right on!

Plates are fine,

Front plate #34
Idle feed .036
Main jet .089-.089

Rear plate #35
Idle feed .036
Main jet .086 right .093 left

Kill bleeds .043

Idle air bleeds .055

High speed bleed.038

Throttle blade hole.078

This is what I found on 3 stock 1970 440 setups, 69s are not the same, 340 is not the same The mopar performance #34, #35 plates match this, some later plates did not match for me, had smaller jets. If this is wrong hopefully someone will correct.

Some have said their promax plates had bigger idle feeds so check to be sure. Match a stock 34 and 35 plate to start.

[quote=4406bbl]Plates are fine,

Front plate #34
Idle feed .036
Main jet .089-.089

Rear plate #35
Idle feed .036
Main jet .086 right .093 left

Kill bleeds .043

Idle air bleeds .055

High speed bleed.038

Throttle blade hole.078

This is what I found on 3 stock 1970 440 setups, 69s are not the same, 340 is not the same The mopar performance #34, #35 plates match this, some later plates did not match for me, had smaller jets. If this is wrong hopefully someone will correct.

Some have said their promax plates had bigger idle feeds so check to be sure. Match a stock 34 and 35 plate to start.

You seem very knowledgeable about the plates. Do you know what the sizes are on the 340 plates? I had heard that BLP makes the plates and blocks for Pro max true?

I've been using those Promax metering plates for the last 15 yrs. No problems with mine. The thing I like about them is you can change jets very easy and not have to worry about finding a stock set of plates. I also don't have to worry about drilling larger size holes in the stock plates. You can drill bigger but not smaller holes. It does include a jetting guide.

Sorry I do not know much, just wish those that do know would post the exact stock orifice sizes for the 340 and 440 setup, that way a person would know what they have. It gets a little old seeing people post, oh just return it all to stock size and start there, what is truly stock size? I am pretty sure my 440 specs are correct as I have not been corrected, usually if you post something wrong here you will find out fast. The #34 and #35 plates that you buy from holley now are wrong, or the catalog specs are wrongfor a 6bbl. For the 340 I have little info, #41 plates, .067 kill bleeds. Holley catalog says #41 plate is .033 idle bleed, and .070 main jet....I doubt thats correct for a 6bbl. I sold the 340 stuff off years ago, if I had one I would tear it down and give you the info. Maybe someone that has a 340 that runs right could post what they have next time it is apart.

I've used those blue gaskets before, they tore on the first removal, worse than stock gaskets.

Thats weird, I have used quick fuel and holley blue with no issues. Wonder if there are cheap knockoffs out there.

Add a VERY light coat of vaseline or white grease to the gasket surfaces and they'll come off a lot easier.

I figured out how to read the jetting guide. My OE plates were definitely modified.

they work real good - I cried when i saw you sold them
never can watch all the ads....

I believe some of my Holley catalogues have the specs for the metering plates. I'll dig them out tomorrow and see what I find.

Here's what my old Holley catalogues have comparing plate numbers to idle restrictions and jet sizes.

OK I may be a dummy but there was never a meter block on the out board carbs I don't have any on mine there just the to dump gas????

No metering blocks on outboards, they use metering plates. The holley chart above is incorrect for a 6bbl. A #34 plate with a .052 main jet will not work in any 1-3/4 plate carb, nor will the #35 with .071 jet. 2 #27 or #5s would be a decent start.

Thanks for the information. The two metering plates in my end carburetors had a stamping of #41 with a casting #34R-6153B. The PVCR (Power Valve Channel Restriction) or jetting (fig. A above) is staggered at .086 (driver side) and .073 (pass side) with the Secondary Idle Speed Restriction being .036 on both plates (front & rear carb), driver and pass side. Based on the parts book and what I am understanding then, the metering plates were the same for both front and rear carbs.

Is anyone familiar with how many turns out the air mixture screws were set from the factory on the end carbs? I know this must have been a very precise setting because all end carbs came with "plugs" over the adjusting needles so they couldn't be messed with.

Thanks

As an original owner of an A12, if my memory (I'm 77) serves me right, when I tried to improve the bad idle
characteristics, the screws were barely, if at all, off the seats.

The best results were 1/8 or a 1/4 turn off the seat.

Joe

I just finished two sets of A12 carbs,one for a member here and the other a member on the A12 site that still had the original lead plugs,both sets were out exactly two turns except the driver side front left on the one set and it was 1 3/4 turns out.

So much for my memory...LOL

Joe

Has anyone here had any problems with the floats hitting the plates?

Only with longer jets.

They Fit Nicely
with normal jets

You can actually modify the stock metering plates to accept jets. Plug the orifices with lead and drill and tap for jets.

We put the promax plates on my car two weeks ago. Do a little search on the internet about Bob K and he shows how to jet them. I understand every car is a little different but he gives a good base line of where to start.

I have... I never figured out the root cause of the issue other than float and bowl tolerance stack up. Some of the float designs were slightly closer to the plate than others. We had to file down the parting line on a nitrophyl float on the dyno to finish the day.

[quote=jlatess


The best results were 1/8 or a 1/4 turn off the seat.Joe [/quote]

I'm running the Promax plates in my outboards. I think my '70 carbs uses a 34 & a 35 plate and I couldn't find one of them (one is common, the other isn't) & my plates had been drilled. I was trying to get back to "factory settings". After extensive research, I put in jets that matched the stock metering plate holes AND changed out the secondary idle feed restrictions. I had to call Promax to get the idle feel restrictors (not on their website) and they had some the correct size (pretty cheap, but I did have to put a propane torch on one to get it out)

Quick fuel also makes the jetable plates.