Six Pack on center carb only?

33 IMP · Mar 6, 2018

Does an untouched 6pack manifold have a specific cylinder or cylinders that consistently run leaner than the rest? If so, those are the ones to look at.

dvw · Mar 7, 2018

Maybe he needs three tiny little twinky-dink air cleaners, and a big-*** fan, lol.[/QUOTE]
Don't laugh. I watched a very good N/SS racer install small restrictive paper air filters. Adjusting ET by poking holes in them. He went on to win that day.
Doug

66Satellite47 · Mar 7, 2018

IQ52 said:
That run was just for grins and giggles and I've thrown the dyno sheet away, so there is no record left of the vacuum. I'd have to put a new room in the shop if I kept every dyno sheet.

The center carburetor is (and was on that dyno run) 350 cfm, and the outboards are 500 cfm, so 1350 cfm total. So then, this equates to about, what, a 960 cfm 4-bbl? I knew exactly once.

The conversion factor from 2BBL CFM to 4BBL CFM is 2BBL CFM / 1.414 = 4BBL CFM. The 1.414 comes from square root of 3 / square root 1.5

Controlling the vacuum source or limiting end carb(or all three) opening still seems like the safest, most consistant methods.

lewtot184 · Mar 7, 2018

33 IMP said:
Does an untouched 6pack manifold have a specific cylinder or cylinders that consistently run leaner than the rest? If so, those are the ones to look at.

hughes website has a flow test on a 6pak manifold. this may help you a little.

IQ52 · Mar 7, 2018

lewtot184 said:
the 1350cfm rating is at 3"hg. original rating on the carbs was 250 center, 390 ends at 1.5"hg. but 1030 doesn't market as good as 1350.

Ah yes, I didn't pay full attention to what vacuum you were rating the carburetors I guess then we didn't do too bad with 360 hp @ 250 cfm 4-bbl equivalent. Wonder what some tuning would have given us?

lewtot184 · Mar 7, 2018

IQ52 said:
Ah yes, I didn't pay full attention to what vacuum you were rating the carburetors I guess then we didn't do too bad with 360 hp @ 250 cfm 4-bbl equivalent. Wonder what some tuning would have given us?

a WOT vacuum number and at what rpm would've been cool info. I bet it was well above 3"hg. VE was probably way down, but really surprised at 360hp. I always figured the center carb was crapped out 3000rpm.

69 GTX · Mar 7, 2018

I have the drawing at home Jim made for me on which cylinders go to which to which barrel. If I remember correctly they also split or share. I know Jim had egt's hooked up to get the jetting correct. Also I think the outboards were stagger jetted but the center carb wasn't,

lewtot184 · Mar 7, 2018

older mopar 6bbl race jet specs:

center carb: #65 main jets, .052" PVCR (both sides; factory is staggered)

front carb: throttle side-.093" diaphragm side- .089"

rear carb: throttle side- .093" diaphragm side- .099"

front and rear idle feed restriction .070" ( I don't think i'd do this unless the manifold vacuum was very low. the factory idle feed/air bleed combination is biased a little heavy toward the rich side.)

oldbee · Mar 7, 2018

lewtot184 said:
older mopar 6bbl race jet specs:

center carb: #65 main jets, .052" PVCR (both sides; factory is staggered)

front carb: throttle side-.093" diaphragm side- .089"

rear carb: throttle side- .093" diaphragm side- .099"

front and rear idle feed restriction .070" ( I don't think i'd do this unless the manifold vacuum was very low. the factory idle feed/air bleed combination is biased a little heavy toward the rich side.)

Were there any distribution tabs added to booster/boosters? Seem to remember.....

lewtot184 · Mar 7, 2018

oldbee said:
Were there any distribution tabs added to booster/boosters? Seem to remember.....

340's had snivies, 440's didn't.

Cranky · Mar 7, 2018

lewtot184 said:
340's had snivies, 440's didn't.

What the heck is snivies? lol

lewtot184 · Mar 7, 2018

Cranky said:
What the heck is snivies? lol

distribution tab, the little thingys that stick out from the boosters.

Cranky · Mar 7, 2018

lewtot184 said:
distribution tab, the little thingys that stick out from the boosters.

lol....ok

oldbee · Mar 7, 2018

Cranky said:
lol....ok

You know, ‘those’ little thingys.

lewtot184 · Mar 7, 2018

didn't you old guys read your ma mopar race/tune-up bulletins back in the day? actually I believe the term "snivey" came from the distribution tabs on AFB clusters.

Cranky · Mar 7, 2018

oldbee said:
You know, ‘those’ little thingys.

A buddy of mine is always calling things 'thingys' and whenever he comes over, it's usually with an 'ish' after the time.....6ish. Ok-ish

Cranky · Mar 7, 2018

lewtot184 said:
didn't you old guys read your ma mopar race/tune-up bulletins back in the day? actually I believe the term "snivey" came from the distribution tabs on AFB clusters.

I must have missed that one somewhere along the line

oldbee · Mar 7, 2018

lewtot184 said:
didn't you old guys read your ma mopar race/tune-up bulletins back in the day? actually I believe the term "snivey" came from the distribution tabs on AFB clusters.

LOL, I love reading, even about 6-bbls that I never owned.

lewtot184 · Mar 7, 2018

oldbee said:
LOL, I love reading, even about 6-bbls that I never owned.

I've tried to save that old info.

Six Pack on center carb only?

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