Inliners International Forums General Discussion Hi Performance So I bought this intake.......now what?

I’m in the process of building a ’37 Chevy Tudor with a 292 Chevy 6. This is an old timey style hot rod, with a noticeable rake, due to the Heidt’s front end and big and little rubber.

I planned on using multiple carburetion, admittedly mostly for looks. So, I found a Clifford 2 X 4 manifold and paid more than I wanted to, but wound up with a good foundation for what I wanted to do.

The original plan was to use 2 Holley 2300 2 barrels, probably mounted sideways. When the manifold arrived, I started dragging out the various bits and pieces I had to see how this was going to go together, and what else I might need.

What I have is three 2300s. Of course, no two are alike. I have a 650, a 500 and an Economaster which I believe to be a 350. Now, all I have to do is buy another carb to match one of these. The 350 is the likely candidate, as the engine will be quite mild (still stock right now).

But here is the dilemma. The carb mounting surfaces are machined in two different planes. The front one has the flange tilted back about 2.5 degrees and the rear is tilted forward about a half degree. And, they are at slightly different heights.

None of this is rocket surgery. Having done this stuff for over 50 years, I’m used to the idiosyncrasies of hot rod parts (especially old ones). And as an old drag racer, I know sometimes you just have to make what you want. Fortunately, I have not mounted the engine permanently at this point. As it sits right now, the engine tilts down in the back about 4.5 degrees with the car at ride height and the stock carb level.

My questions:
How would you guys go about this? Would you start by machining the manifold to the proper angle and then make spacer/adaptors to mount the carbs? Or would you just make the adaptors (extra thick), bolt them on, and then machine the whole mess to the proper angle, then put the mounting studs in perpendicular to the top surface. I’d like to keep the tops in the same plane to allow a single air cleaner.
Would you mount the carbs centered over the manifold openings or bring them out and line up the outside of the throttle bores with the outboard wall of the plenum?
Also, anybody think that I should scrap the carb idea and put in dual throttle bodies? (EFI-DIY, I think I know what you will say.)
I might take this opportunity to level out the engine or even angle it down in the front to match the rake of the car. I have plenty of room to do this.
By the way, the carb mounting (no adaptors) is not square. It is approximately 3 7/8” X 3 3/4”. I think this might be the same as a WCFB.
Any other ideas are welcome.
Will post pictures if you like and updates as we go. This is not my top priority but I want to get a plan in place.

I would mount the new adapters/spacers to the original angle of the intake, then correct the carb mounting angle/surfaces on the topside of the adapters/spacers and drill and tap so they will be in the same plane as needed.

What do you think about the carb placement?

I would run the throttle shafts parallel to the head.

Right, I meant would you center the throttle bores over the carb openings (left to right) or offset them toward the outside so they are tangent to the inside of the plenum wall.

I think it would be ok to center them with the original carb openings.

Well upon further investigation, I found that the carb mounting pads were out of plane with each other in every possible way.
The front carb tilted down at the back at 1.5 degrees, the rear forward at .5 degrees, the front down at the flange side 1 degree and the back up at the flange side 1 degree. Also, the rear carb pad is at least 1/8" higher than the front (not due to the angles but from a horizontal line).

So, I decided to correct the manifold and not machine the adaptors to compensate making them totally useless for any other application. Plus, they would look funny.

I did happen to have two 3/4" plate adaptors to mount a 2 barrel Holley on a 4 barrel manifold. (No identification, but they look like some Moroso ones I have seen.) I drilled and countersunk the four holes to mount them sideways. Then decided to add 4 more to put them inline if I ever wanted to try it.

Now to mill the manifold and put a couple of matching carbs together and work out the linkage and.................

Clifford still has the adapters I believe. I bought 2 of them for my manifold a few years back. The Offy and Clifford are indeed made for the small base Carter WCFB and the Rochester 4GC (Holley teapot too). Two of those would be cool. Funny my Cifford is perfectly flat........Good Luck

I'm not sure you're going to like this: a 292" motor with (at least) 700 CFM worth of primaries.
No auto engine has that, regardless of size.

Panic has a point, though its really only 500cfm by the standard 1.5" Hg rating (a 350 Holley 2bbl flows about 250cfm at 1.5" Hg).

Still, thats a lot of primary.
What about progressive linkage?
Not ideal, since the primary carb has to reach back to feed some far away cylinders. Still, the HiPerf Buick straight-8 cars did this, twin 2bbl carbs and progressive linkage.

Not sure anybody else did this. Hudson "Twin H" was simultaneous.

I did quite a bit of investigation before starting this.
As you say Deuce Coupe, to compare the ratings of 2 barrel to 4 requires a division factor of 1.4
Now, 500 cfm of carburetor on a 300 inch engine isn't all that much especially with a mild to moderate cam.
The carbs I'm using are Economasters that are pretty lean to start with. With some accelerator pump work (shooters and cams)and jets, I'm pretty sure I can dial this combination in to a very livable package.

We have to remember, the cfm ratings for carburetors are for WOT. The cfm delivered (actually, 'available') is a function of the driver's right foot.

The fun is in trying something you think might work, and if it does you feel pretty smart. If not, you learned something anyway. Plan 'B' is still available.

Ideally, I would like staged 2 barrels. (Holley 2305s?) Also, T. Lowe built his own staged 2 bbl but didn't pursue it. I might do my interpretation of this.

Plan 'C' is the possibility of using two TBIs.

As I stated in my original post, the main reason to try this was mostly for appearance, secondarily for more even fuel distribution. I'd like to use as many parts from my collection as possible.

We'll see.

I think you will be fine with a pair of 350 cfm 2300s. Consider that the cylinder size of a 300 cube 6 vs 300 cube v8 is physically larger so there is more space to put more stuff so to speak. Also, don't forget that the 500 cfm is spread over the length of the manifold. The 500 figure is also at WOT. I think the slightly more important question with respect to the manifold is whether you have one of the earlier manifolds without a provision for water heat or one of the newer versions that does. The lack of heat to the bottom of the manifold will cause more problems than the carbs will with respect to tuning and drivability, in my very humble opinion.

Yep, this is an early manifold. I have been looking at ways to add water heat. I'm sure you're right abut the importance of the heat.

Luckily, I recently purchased a TIG welder. What a nice accessory. Now, I have a reason to use it.

Thanx for the comment,

Bruce