I saw a you-tube video where a young guy had a carb mounted to the top of an efi manifold. Seams like it would be too high to close a hood.
I was wondering if anyone ever made an adapter block to mount a carb in place of the throttle body, instead of buying an offy manifold?
john

 

Here is your golden opportunity! Do it with plenty of before, during and after pictures, detailed progressive write-ups and of course, before and after performance evaluations.

 

This is the only image I've seen of someone using the EFI lower intake to mount a carb. From the look of it, the carb would be raised up a few inches from where the standard 4bbl intakes would put it.
That said, in the trucks, there's a lot of room between the top of the air cleaner and the hood. My carb sat on a 1" spacer and I have a pretty big air cleaner (about 4" tall) and the hold down stud protrudes another inch or two above that to make it easy to get the butterfly nut onto, with no clearance issues.

As for a carb in place of the throttle body, are you meaning one that sticks off the side of the upper part of the intake? Like a Weber carb or something?

 

My thought was to take a 90 degree pipe bend or square tubing, Weld a flange on end to connect to the upper manifold, where the throttle body would connect.. Then make a carb mounting surface at the other end. Besides making a heating plate, I was wondering if the distance from the carb to the intake ports might cause a delayed throttle response.

 

I don't know from experience, but I do agree that that would cause quite a delay in throttle response. That's a long way from the engine. It only works on the EFI model because the injectors are right in front of the intake ports, so the air through the intake can take however long it wants. But if you're having fuel come in way back at the throttle body, and then travelling through the upper and lower plenum of that intake, that's going to take a while.

 

That's your problem right there! Just toss your hood!


This isn't my car but I've had the pictures for a few years.




Anything is possible with enough time, energy, effort or money. Making a adapter/carb mount, that goes in place of the throttle body, may work. How well? Who knows! I don't think that is something very many people have tried. Just guessing it would probably work quite well at WOT ( think tunnel ram on a V8 ) . But driveability issues may pop up from the carb being so far away from the cylinder head. The fuel may drop out of the air fuel mixture.

If you want to try it, then try it. If it works, great! If it doesn't then you need to try something else.

 

Not only that, but every time you ask the air to turn when its carrying a "wet" mixture of fuel you are asking for problems. The air can turn relatively easily. The fuel droplets - not so much. They have a tendency to impinge on to the manifold wall, and stick there, slowly trickling downstream. That will also cause driveability issues.

 

What FTF said is spot on.

You could probably get away with using side drafts in place of the OE throttle body since the 180 turn into the ports is such a large radius.

 

Here is another example of a modified F.I. upper intake manifold. I am sorry that it is so large.

 

A buddy mentioned the side drafts, but they look a little spendy to just be experimenting. The pic AB posted made me think about attaching some tubing to the lower intake manifold and welding a carb mount on the top of it. I have a friend who welds and I can get the materials cheap.,

 

Older outboard motors in the 200+ hp range will have carbs that are about the right size (usually duals or triples). The probably won't be all that great in a daily driver application but if you just want to experiment you can probably fine some fairly cheaply.

 

Or, something like these: https://www.ebay.com/itm/SU-Carburet...nm0:rk:40:pf:0

 

Dear god. I know the old European car enthusiast crowd has more money than sense but those cost the same as outboard carbs!

https://www.ebay.com/itm/Mercury-Mar...item33edff62bd

Also, I quickly searched Evinrude and it seems cheaper across the board.

Obviously the adapter would be simpler with 2x 1bbl carbs rather than 2x 2bbl but if you're doing flanges and tubes rather than one solid block it's not that much more work.

Also, based on intended application the SU carbs seem kind of small.