I'm Gonna Build A Dragster!

[old28]

11.20's would be a good pass with that motor. Save the cash & put it in the Jeep motor, then drop the motor in the Bullet when you get it done. 10's for sure, might even have to slow it down a bit to stay out of the (NHRA PAY USE 9.99 OR QUICKER FUND).

 

[bob w]

Something New

Today I received a complete EFI manifold from a 300 Ford 6. My Christmas present and an attempt to make the dragster go a little bit quicker. The plan is to cut a hole in the plenum and mount either a 4 barrel or two 2 barrel carbs on it. Hoping the longer runners help this engine. It doesn't run much over 5,000 rpm so maybe the long runners will help low and mid range power. Hoping it behaves like a tunnel ram.

The big question is the manifold is designed to flow air only. The fuel is injected where the ports meets the head. So, will it flow an air-fuel mixture like it flows air only? We'll see.

Here's the set up on the dragster now. Just the lower part of the EFI manifold with a home made plenum and three carbs. Any opinions?

 

[Old Iron]

I know it would be a pain to put linkage on but, on the original manifold, turning the three carbs 90 degrees would facilitate a better flow under the carbs.
I'm gonna sit back and watch ya do the next one.

 

[zzrodder]

I kinda agree with OI about turning the carbs 90 degrees, same goes for the EFI top, turning the 4bbl 90 would also even up the distribution to the ports. I expect you would cut off the throttle body mount and weld in a plate for appearance sake at least...
Longer runners generally do improve low/mid range torque.
Probably the biggest issue with carbureting a dry manifold like this is the plenum volume, smaller is generally better for throttle response and avoiding the dreaded bog when you stomp on it.
Here's a thought - if you are removing the throttle body boss, putting a removable cover on it would give you access to fit different size/shape deflectors or contoured "plugs" into the plenum to reduce volume and direct flow to the ports.....[S[S

 

[bob w]

I watch dyno tests on You Tube by Richard Holdener. Then I looked up how the Ramchargers calculated runner length on the "High & Mighty" Plymouth gasser back in the day. That's what got me interested in runner length. Looking inside this upper manifold it has two plenums, one for the front 3 cylinders and one for the back three. Like a dual plane manifold. There's "V" shaped area in the middle that is not plenum area. This manifold really wants two carbs, just like it had a two throat throttle body that did not feed into a common plenum.

 

[zzrodder]

OK, that puts a different spin on it, sounds like you're on the right track with dual carbs.[P[P

 

[soltz]

I'll be following along with set up. Might make my daily 300 incher something different [S

 

[Dr Crankenstein]

I'd like to see a cross section of that manifold. [S

.

 

[bob w]

I'd like to see a cross section of that manifold. [S

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I would too, Doc. I've peered into it with a penlight. I'll take dimensions and draw a picture of the runners and plenums. But for now it's back to the Crosley.

 

[Dr Crankenstein]

I would too, Doc. I've peered into it with a penlight. I'll take dimensions and draw a picture of the runners and plenums. But for now it's back to the Crosley.

 

[bob w]

A Little More Info

After I did my work on the Crosley I couldn't help but look at the manifold again. The black "V" is no man's land and not part of either plenum. There is an internal partition on either side of the "V" defining the boundary of each plenum. I intend to cut off the throttle body mount extending beyond the box.
A Ford 6 expert I sorta know pointed out that using roller rockers requires a taller valve cover. I know that and have fabbed a taller valve cover. The rub he pointed out is the manifold will not clear a taller valve cover. Probably will have to make a spacer between the lower and upper manifold sections.

 

[Dr Crankenstein]

Are the box halves wide open, or can you tell?

.

 

[bob w]

YUP

Are the box halves wide open, or can you tell?

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Yes, the runners end at the entry to the box. Likewise, the throttle body tubes end at the entry to the box on the other side. So each plenum is independent, except for a small balance port. Should be good to go.

 

[Dr Crankenstein]

Yes, the runners end at the entry to the box. Likewise, the throttle body tubes end at the entry to the box on the other side. So each plenum is independent, except for a small balance port. Should be good to go.

A pair of 2 barrels seems the logical choice now, doesn't it?

.

 

[bob w]

Making chips

I cut the mounting area for the throttle bodies off, figured out how to mount the Autolite 2 barrels and cut the bores with a hole saw. A 1/2" thick plate will be needed to mount each carb. They will be bolted on and sealed with JB Weld. As will the block off plate on the side of the plenum.

 

[Old Iron]

That look great.
[P[P[P

 

[bob w]

Makin' Chips

I picked up a couple chunks of 1/2" aluminum to make the carb spacers. After a few days nursing my overused shoulder, I got back into it a bit and cut the throttle bores with a hole saw in the drill press.
BTW the holes in the gasket are much bigger than the carb throttle bores.

 

[bob w]

Got the carb mounting plates finished. Next they will be bonded to the plenum.

 

[DozerII]

[P[P[P interesting

 

[bob w]

The linkage is just about done. There's some welding and finishing left. In the third pic the cross shaft isn't centered. It'll be a shame if the car goes slower with this set up. But, that's drag racing.