Six bbl jet recomendations

[440+6]

I had a few bowl leaks on my six bbl so I did a quick rebuild and found #34 metering plates in both outboard carbs, I decided to go with the Quickfuel plates but I'm not sure what to use for jets.
My understanding is that it should have #34 plate in front (#79 jets both sides) and #35 rear (#82 #77 jets).
Center carb has #64 jets
Any ideas on what jetting I should go with? I have read that these came out of the factory a bit lean, as it is I had the wrong plate on my rear carb.

Here is what I got
F440 hp block .030 over six pack replacement pistons 9.5 compression
Dyno when built was HP 437 @ 5250 / Torque 518 @ 4000
906 heads mild bowl port 1.5 steel rockers
Cam is Mopar P4120235 484/484 lift and 241/241 @ .050 and 108 center line
stock hp exhaust manifolds w/ 2.25 pipes
hemi 4 speed 3.54 dana

 

[lewtot184]

a word of caution on those quickfuel plates; the metal plate that goes between the jet plate and carb body has to be the '69 style or 4160 4bbl type , not the '70 and up plates.. also notice that the passages in the quickfuel plates are smaller than stock. I wouldn't get lost in trying to duplicate the stock jetting because your engine isn't stock. i'd start with 80's in all four corners and 64's in the center. I bought a set of the quickfuel plates to try and after looking over the "details" of them I just stuck them back in the drawer.

 

[440+6]

a word of caution on those quickfuel plates; the metal plate that goes between the jet plate and carb body has to be the '69 style or 4160 4bbl type , not the '70 and up plates.. also notice that the passages in the quickfuel plates are smaller than stock. I wouldn't get lost in trying to duplicate the stock jetting because your engine isn't stock. i'd start with 80's in all four corners and 64's in the center. I bought a set of the quickfuel plates to try and after looking over the "details" of them I just stuck them back in the drawer.

When you use the Quickfuel metering plate you do not use the thin metal plate at all, as far as the passages behind the plate they look pretty close to my cast plates, also the idle restriction is .039 and stock is .029, I know allot of people have used them with good success.
I was thinking 78 or 79 jets but maybe 80 could work well also.

I was hoping to get lucky and do this once, that's why I was asking if anyone has more experience than me with jetting six barrel setups.
I was also considering getting a wideband a/f setup to dial it in once and for all, then remove it and sell to someone wanting to do the same ( I have no experience with a/f meters but I am starting to look into them).

 

[clazar]

When you use the Quickfuel metering plate you do not use the thin metal plate at all, as far as the passages behind the plate they look pretty close to my cast plates, also the idle restriction is .039 and stock is .029, I know allot of people have used them with good success.
I was thinking 78 or 79 jets but maybe 80 could work well also.

I was hoping to get lucky and do this once, that's why I was asking if anyone has more experience than me with jetting six barrel setups.
I was also considering getting a wideband a/f setup to dial it in once and for all, then remove it and sell to someone wanting to do the same ( I have no experience with a/f meters but I am starting to look into them).

Try & call Mr Six Pack. i believe his name is Bob Karakashian. AKA Mr Six Pack, 248-477-7776 for day, 248-489-4076 evenings or [email protected]

Chuck

 

[Meep-Meep]

You would be wise to get an A/F setup. The problem I have with mine is a rich condition at light throttle cruise. I can get good idle but it all goes down hill form there. Now that my system is on another car I will resume tuning when that is up and running.

Oh, I have the QF plates in the outboards with 80 / 85 jets (I think those were the correct jet numbers) and staggered as OEM. Note the metering plate restriction orifice is not equivalent to the jet orifice.

 

[440+6]

You would be wise to get an A/F setup. The problem I have with mine is a rich condition at light throttle cruise. I can get good idle but it all goes down hill form there. Now that my system is on another car I will resume tuning when that is up and running.

Oh, I have the QF plates in the outboards with 80 / 85 jets (I think those were the correct jet numbers) and staggered as OEM. Note the metering plate restriction orifice is not equivalent to the jet orifice.

Did you stagger jets on the rear only or both? And I'm a bit confused as to what side is richer when you stagger, I think its the drivers side, is that right?
Yes the plates have two different restrictions, one is for the idle restriction (.039 on the quickfuel plates and can be changed) and the other is the jet size you use, I was using the conversion chart the Promax web site for jet to orifice size to try determine jet sizes from the #34 and 35 stock metering plates and go up a bit from there.

 

[Meep-Meep]

I'll have to look at what I did since it's been a while. I just copied the staggering from the original plates.

 

[68 HEMI GTS]

When you use the Quickfuel metering plate you do not use the thin metal plate at all, as far as the passages behind the plate they look pretty close to my cast plates, also the idle restriction is .039 and stock is .029, I know allot of people have used them with good success.
I was thinking 78 or 79 jets but maybe 80 could work well also.

I was hoping to get lucky and do this once, that's why I was asking if anyone has more experience than me with jetting six barrel setups.
I was also considering getting a wideband a/f setup to dial it in once and for all, then remove it and sell to someone wanting to do the same ( I have no experience with a/f meters but I am starting to look into them).

That’s the problem with them, the gasket gets sucked into the void on the main body without a backing plate.

 

[RJRENTON]

I had a few bowl leaks on my six bbl so I did a quick rebuild and found #34 metering plates in both outboard carbs, I decided to go with the Quickfuel plates but I'm not sure what to use for jets.
My understanding is that it should have #34 plate in front (#79 jets both sides) and #35 rear (#82 #77 jets).
Center carb has #64 jets
Any ideas on what jetting I should go with? I have read that these came out of the factory a bit lean, as it is I had the wrong plate on my rear carb.

Here is what I got
F440 hp block .030 over six pack replacement pistons 9.5 compression
Dyno when built was HP 437 @ 5250 / Torque 518 @ 4000
906 heads mild bowl port 1.5 steel rockers
Cam is Mopar P4120235 484/484 lift and 241/241 @ .050 and 108 center line
stock hp exhaust manifolds w/ 2.25 pipes
hemi 4 speed 3.54 dana

On my 1970 440+6 GTX RS23VOA******, I replaced the front and rear carb jet plstes with the Promax plates with the removable Holley jets. Measure the ID of the origional jet plates using the shank end of a either a letter drill or number drill for sizing (lightly sliding the drill shank into the metering restriction). Do the same for the IDLE feed restriction. This is a close approximation of the diameter of the jet diameter. Compare this dimension with the dimensions of the Holley jet listing as a base line size. Because of your engine mods, you MAY need to go up or down or stagger the jet sizes as determined by testing or spark plug readings or the way the car performs. There is any exact recommend size.....experiment to determine what you want or need......just my opinion of course.....
BOB RENTON