63 Max wedge 3447 original jet sizes

[bobs63wagon]

Anyone know the original primary and secondary jet sizes and metering rod number on the 3447's. Want to help someone out to put them on a 63 Max Wedge street car. At least a good starting point. Thanks for any help.

 

[coloradodave]

From the service bulletin for July 17, 1962 I have the following for #3705-S Carter AFBs:
Primary main jets: .104" (120-161)
Secondary main jets: Throttle lever side: .089" (120-159)
Choke lever side: .063" (120-176)
Step-up rods: Standard .066" X .053" (16-76)
Float setting; 7/32"
I'll keep looking for the 3447s... FOUND IT! LOOK BELOW

 

[coloradodave]

Found the information for 3447s AFBs:
Primary main jets: .098" (120-163)
Secondary main jets: .082" (120-158)
Step-up rods: Standard .068" x .050" (16-51)
Float setting: 7/32"
Float drop: 3/4"
Accelerator pump setting: (top of plunger to airhorn) 7/16
Idle mixture setting: both screws open 1-1.5 turns

THANKS TO DARRELL DAVIS' 1963 PLYMOUTH SUPER STOCK GUIDE BOOK

 

[GTX JOHN]

On the Dyno in our 3447 carbs we ended up with a 76 on the short
runner and a 89 on the long runner. Way different length on the runners.
This is with a production 63 Manifold. The A&A replacement made significantly
more HP and required a bit different jetting. i assume you still have the original
on your wagon.

Let me know if I can be of any help!

 

[Geoff 2]

I wonder if the 098 pri jet is a misprint. The 3447 carbs had the small 1 7/16" pri bores [ versus 1 11/16" for the 3705 carb ]. 1 7/16" pri bore carbs generally had 089 pri jets.

 

[bobs63wagon]

Found the information for 3447s AFBs:
Primary main jets: .098" (120-163)
Secondary main jets: .082" (120-158)
Step-up rods: Standard .068" x .050" (16-51)
Float setting: 7/32"
Float drop: 3/4"
Accelerator pump setting: (top of plunger to airhorn) 7/16
Idle mixture setting: both screws open 1-1.5 turns

THANKS TO DARRELL DAVIS' 1963 PLYMOUTH SUPER STOCK GUIDE BOOK

Thank you for the info and for taking the time to do it.

 

[bobs63wagon]

I wonder if the 098 pri jet is a misprint. The 3447 carbs had the small 1 7/16" pri bores [ versus 1 11/16" for the 3705 carb ]. 1 7/16" pri bore carbs generally had 089 pri jets.

I did see one other place that said 089 primary jets. Thanks.

 

[bobs63wagon]

On the Dyno in our 3447 carbs we ended up with a 76 on the short
runner and a 89 on the long runner. Way different length on the runners.
This is with a production 63 Manifold. The A&A replacement made significantly
more HP and required a bit different jetting. i assume you still have the original
on your wagon.

Let me know if I can be of any help!

I ran the 3447's for awhile but went to the Edelbrock replacement. Never run those on the dyno but will with the new motor. Having my headers fixed for O2 sensors on the dyno this time. Always appreciate your help John.

 

[GTX JOHN]

I will see my Friend Steve Wann next week at Bakersfield
double Divisionals. He is absolutely hands down the fastest
Max Wedge Racer currently racing anywhere. Hopefully he might
tell me a baseline setting for the Edelbrock carbs. These carbs were
not legal when I raced these cars.

I do not think these carbs are any better than the originals (Not
sure even nearly as good), but they are surely easier and way cheaper
to find. The issue with the original Max Wedge carbs is most guy run a
ton of return spring pressure on them and it really wears out the throttle
shafts.

He builds the carbs for a lot of the fastest Max Wedge Racecars
in the country and a lot of the turnkey race engines in for them
as well.

 

[Rebelrouser]

From the Old Mopar performance bible.

1964, 426 Max Wedge Cross-Ram Fresh Air

Carb:	Two Carter AFB 3705S carburetors
Manifold:	Stock Max Wedge Cross-Ram
Manifold Modifications:	one
Carb Specifications:	Two Carter AFB 3705S carburetors
	Left Carburetor​
	Throttle Side​	Diaphram Side​
Primary Jet:	120-410 (.110")​	120-410 (.110")​
Secondary Jet:	120-392 (.092")​	120-392 (.092")​
Metering Rods:	PT​ WOT 16-76 (.066" x .053")	​
	Right Carburetor​
	Throttle Side​	Diaphram Side​
Primary Jet:	120-407 (.107")​	120-407 (.107")​
Secondary Jet:	120-389 (.089")​	120-365 (.065")​
Metering Rods:	PT​ WOT 16-76 (.066" x .053")	​
Note: Same jets used for increased interconnection manifold (10 in.2 and 55 in.1). See Figure D.
Air Cleaner:	Ideal Entry

Special Note: The modified interconnection manifold shown in Figure D has not been proven to be better than standard. Also, it has not been run on the dynamometer to revise the above carb specifications. On the 1964 Max Wedge, the increased interconnection does not appear to be a performance improvement.

 

[Geoff 2]

GTX John.
Couple of thoughts on the 3447s.
[1]They have the small airhorn & flow about 575 cfm. The Edel 600 carbs have the same venturi & t/bore size, but with the larger 5" air horn flow about 600-625 cfm. If the engine can use the extra airflow, might be a benefit.
[2] If you remove the airhorns from the 3447 & Edel, I think you will find they interchange. So you could use The Ed top on the 3447 body for more airflow.
[3] I suspect the boosters will also interchange. You would need to check the height of the 'shelf' that the boosters sit on & compare between carbs, because this could affect float level.
Good luck.

 

[bobs63wagon]

GTX John.
Couple of thoughts on the 3447s.
[1]They have the small airhorn & flow about 575 cfm. The Edel 600 carbs have the same venturi & t/bore size, but with the larger 5" air horn flow about 600-625 cfm. If the engine can use the extra airflow, might be a benefit.
[2] If you remove the airhorns from the 3447 & Edel, I think you will find they interchange. So you could use The Ed top on the 3447 body for more airflow.
[3] I suspect the boosters will also interchange. You would need to check the height of the 'shelf' that the boosters sit on & compare between carbs, because this could affect float level.
Good luck.

I have had the 1405's worked on and should be fine. They can work on the 63's as a 63 car in C/SA I know has run 10.40's with them. Hope my new high compression 63 motor makes some hp close to his. I did run the big tops on the 3447's and seemed ok. Just seemed to idle better with the edelbrocks. Now my next question that I will ask everyone is if the 64 intake is better than the 63. This motor will have 518M heads, which are 64 heads and wonder if the 64 intake will work better. I'll ask and see what I get.

 

[GTX JOHN]

PM sent

I think any of the Carbs have plenty of Air flow
for these engines.

I never found much difference between HP on 3447
and 3705.

Once (You can Believe it or not) I unhooked the Secondaries and only
lost 3 tenths on the 3705.