Angle to mill intake

[dmsmith55]

When milling for direct mount Holley 2bbl, do I maintain the angle of the original carb flange, or can I fudge it a little to more closely match the top od the log???? I know the original angle was there to keep the carb level when the engine is in the car at a slight angle; how critical is level with the center pivot float equipped Holley???

 

[wsa111]

Try to keep as close to the original angle, may be necessary to fill in the low areas so this can be done.

You can also angle mill the adapter plate between the log & the carb if there is not enough meat on the log.

Try to keep the carb level when the engine is in the car. William

 

[Hot 6t Falcon]

Howdy,

I cut the manifold flush with the top of the manifold. Welding adds to the cost.

William has a good theory about keeping the carb level, BUT in actual practic it doesn't seem to make much difference.

Consider that you are also turning the carb 90 degrees from Ford's intention.

I use an Autolite 1.21 351 cfm on my well-modified 200. The float's pivot point is to the rear. Seems to work just fine.

 

[dmsmith55]

Thanks, guys. It does kinda look like maintaining the carb base angle would put the cut too deep on the front side before I got a flat spot big enough for an adaptor plate. I wonder what MustangGeezer used for angle?? I will look up on of his messages and PM him.

 

[XFlow_Fairlane]

I milled mine level. reason being is that it makes the machine work much easier to do and that I am making new motor mounts and tranny mount to raise up the tailshaft an inch or two. from teh looks of it I will be running a level engine since it sits so low.

 

[wsa111]

I still stress the need to keep the carburetor level or even tilting forward, because on acceration the fuel will slosh to the back of the bowl.

To keep it level maintains the proper float level on each venturi for proper fuel distributation. That is the sole purpose of setting the float level in the first place.

Do it right the first time & get your carb level as designed by ford, with the 2 barrel carb this is essential.

Yes it will cost you more in filling in low areas of the log or angle milling the adapter but if you are spending $$ to put a larger carb on at least step up to the cash register. William

 

[xctasy]

On the highway, the carb should indeed sit level. 99% of domestic rear drive engines are leaned back 3.5 degrees from the front crank pully to the back of the flywheel.

Side to side, they are level. The float level is adjusted to a certain height, and like Will says, the manifold mount should ensure the original rate of desent is maintained, or the car won't run cleanly becasue one jet will have more gasoline presure than the other.

 

[addo]

FYI, the carb pad angle on a 2V is about 7°. I suppose it's similar on a log head. My theory is that most of the angle is imparted so the round air cleaner doesn't foul the lid!

 

[xctasy]

Wow, considering the 39 mm element height, I'd say you are right addo.


Any carb can 'hack' a 5 degree inward lean as log as each jet has the same amout of fuel above it stock. So a set of DCOE 45's can be angled on a 5 degree downward draft.

On a Holley, your better to make it sit leve in all plans. They are great, tunabl;e carbs, but you'd need to do a lot of work to make it run right if the carb was sitting on a 3 or 4 degree downward lean. The back barrel would get too mch fuel, the front one too little.

 

[Anonymous]

I really don't think a few degrees tilt has any noticable effect on a street run carb. Unless you live in Kansas or Florida the carb doesn't sit level anyways. In many areas you may drive hours at a time with the carb at a pretty noticeable angle simply because the roads are not level. The wieght of the fual contained in a float bowl is not sufficient to change the fuel pressure through the jets due to an out of level carb. I was brought up in the Adirondack Mts. and the only time a carb was level was when in a garage. As was mentioned the biggest concern on these sixes is usually hood clearance for the breather.

 

[xctasy]

There is a huge change with gradient to the proper operation of a carb. Normal along the road gradients on some of the steeper mounted passes ar 12%, 4 times, normal camber (crossfall) on a road is often 3%. Normal superelevation, (the buildup of the outside of a corner) on a road can go up to 10% on tighter corners. The fuel level in Holley carbs, more than any other carb, has a vast affect on the fuel consumption. If you get the float level out just a little, you can never trace the fault back to anything concrete. The sight glass is designed around the carb being level to the ground, and with a width of 1.875" between both main jets, a 12% grade will alter the stage fuel height by almost a quarter of an inches, the full depth of the sight plug. This is enough to upset the calibration.

I've seen Holley 1-bbls on Offy/Clifford tripple manifolds, but they are mounted like they are on V8's, not spun around like on our sixes.

Angling the carb does change the jetting requirements. A 3.5 degree change in the direct mount 2300 instillation is like driving up a 6% grade all day, very different to the way the Holleys are mounted in the V8 cars.

In our sixes, the power valve and main jets will get closer to getting exposed on an upward 12% gradient, and having a the car mounted flat to the head could result in the carb behaving like it was on a 15% gradient.



Holleys are great carbs, but they have limitations when the going gets rough, steep, or when we side mount them on our sixes. This was not the way Holley intended them to be mounted, and even a few degrees is enough to upset things.