Carburettors backwards?

[fortyonerag]

Folks,

Pardon me while I ruminate for a bit.

I have a dual intake manifold for my 59 flathead marked Hexagon Tool Company. The carbs face backwards. I understand that the manifold was intended for front wheel drive race cars, so the carbs would then be facing in the correct direction - bowls facing front. The manifold came on an engine I rebuilt.

I see some reports on the 'net saying that these manifolds can be run successfully on the street, but this would mean the carbs would be facing backwards - bowls facing the back.

The benefit, I guess, is that it would allow a stock generator location with carbs evenly spaced across the intake runners.

Buut, there must be a reason why all manifolds I'm aware of have the carb bowls facing to the front. Fuel flowing away from the carb body under heavy acceleration? Not something I expect to experience.

Apart from linkages and such, what kind of operational issues could I expect to experience on the street with backwards carbs?

 

[alchemy]

Stromberg floats hinge at the side. I would think the bowl isn’t effected much by forward or backward.

 

[Ziggster]

My understanding is that the flathead engines were to be basically level once installed, so if that was/is true, it shouldn’t matter. Even if it did, I would think for at least Holley 94s, any affect of having the carbs mounted “backwards” could be accounted for by adjusting the float height. Cool intake!

 

[Ziggster]

I have an Edmunds 2 x 2 intake, and for comparison purposes, you can see how much the secondary carb is biased towards the rear. The primary carb is actually in the same axial location as a stk Ford intake. I can just barely mount the generator in the stk location.

 

[Strick]

Another usage for this intake was for boats from what I understand.

 

[tubman]

As I understand it, pre-49 flatheads were mounted level, while the 8BA series has a 3 or 4 degree tilt. If you look at the respective intake manifolds you can see the difference.

As to mounting carburetors backwards, I do it when I use the Rochester 2G's on a Merc manifold. That way, the linkage and fuel lines just about fall into place. Although the float bowl is now in the back, I can detect no difference in performance. While it may be a factor with a car capable of ferocious acceleration, it will make no significant difference on a flathead. I believe that 390 Holley 4 BBLS also work better mounted backwards.

 

[fortyonerag]

Another usage for this intake was for boats from what I understand.

I get "Oh, a boat manifold" quite a lot

 

[petehoovie]

Folks,

Pardon me while I ruminate for a bit.

I have a dual intake manifold for my 59 flathead marked Hexagon Tool Company. The carbs face backwards. I understand that the manifold was intended for front wheel drive race cars, so the carbs would then be facing in the correct direction - bowls facing front. The manifold came on an engine I rebuilt.

I see some reports on the 'net saying that these manifolds can be run successfully on the street, but this would mean the carbs would be facing backwards - bowls facing the back.

The benefit, I guess, is that it would allow a stock generator location with carbs evenly spaced across the intake runners.

Buut, there must be a reason why all manifolds I'm aware of have the carb bowls facing to the front. Fuel flowing away from the carb body under heavy acceleration? Not something I expect to experience.

Apart from linkages and such, what kind of operational issues could I expect to experience on the street with backwards carbs?

 

[Tim Ayers]

The Hexagon Tool intake was first designed to run on the '35 Miller Indy cars which were front wheel drive. In this set up, the carbs are facing forward because the motor was set in the car backwards. Approximately 12 years later, someone recast these and sold them. The can absolutely be used on the street. Takes a bit to figure out the linkage, but they run well. The design also allows the carbs to sit over the ports while still using the generator straight up.

I'm fortunate to have an early version of this intake with the "D" base carb pads and an original air cleaner. The air cleaner really sets it off.

 

[fortyonerag]

Tim, thanks. That explains the patent date of 6.4.47 on the manifold. Thought it was a bit late for a front wheel drive flathead race car

I have seen pics of the air cleaner, I agree it looks great.

I understand they were reppoped a few years back but are now scarce. I'd love one!

 

[mfirth]

That carb/generator clearance is what we called "a scoshie bit" back in the day.
Thanks pete for always enlarging !

 

[B Munroe]

I ended up making reversing plates so my generator fits without hitting the front bowl. The only issue was the early fuel pump riser had to be replaced with an later one that rotated the fuel pump straight out to the side.

 

[Tim Ayers]

Tim, thanks. That explains the patent date of 6.4.47 on the manifold. Thought it was a bit late for a front wheel drive flathead race car

I have seen pics of the air cleaner, I agree it looks great.

I understand they were reppoped a few years back but are now scarce. I'd love one!

Yes, the repops show up once in a while. I had a repop and sold it as a set with the intake. After finding the earlier D base one and original air cleaner, I plan to hold on to it for a bit.

If you do find a repop, make sure it's for a Hexagon Tool intake. The hole spacing is odd. It's 5.25" if I recall correctly and will only fit a Hexagon Tool intake. I believe someone was making them for other intakes as well.

Here is a picture of the air cleaner.

 

[petehoovie]

Yes, the repops show up once in a while. I had a repop and sold it as a set with the intake. After finding the earlier D base one and original air cleaner, I plan to hold on to it for a bit.

If you do find a repop, make sure it's for a Hexagon Tool intake. The hole spacing is odd. It's 5.25" if I recall correctly and will only fit a Hexagon Tool intake. I believe someone was making them for other intakes as well.

Here is a picture of the air cleaner.

 

[fortyonerag]

Here's the 'scoshie bit' for the Hexagon:

 

[fortyonerag]

Tim,

Many thanks for the heads up on the repop aircleaners, I'll keep that in mind. I think I saw a Hexagon aircleaner on a Thickstun PM7 once. This would explain it.

I measured something like 5 1/8" between carb studs. Sound right to you? I might be doing it wrong

 

[petehoovie]

Here's the 'scoshie bit' for the Hexagon:

 

[jeepguy1948]

The orientation of the carbs may not be related to a for and aff situation. Possibly it’s because race cars are always turning left. That can have a significant effect on fuel in the bowl.

 

[Ronnieroadster]

The Hexagon Tool intake is one of the best running two deuce intakes if your able to find one. This intakes medium riser height design is an additional improvement over many of the conventual height intakes for a bit more horsepower. Plus as noted above an added bonus is it clears the stock generator location.
Ronniroadster

 

[KiWinUS]

The orientation of the carbs may not be related to a for and aff situation. Possibly it’s because race cars are always turning left. That can have a significant effect on fuel in the bowl.

They are???? What about road race cars they are not always turning left or Drag race cars they only go straight when racing or Bonneville race cars? Typical carburetors running on flathead engines eg. Stromberg 97 or Ford/Holley 94 carbs have side pivot floats where left or right turns make no significant difference as they were designed for street driving where all conditions are taken into account.