Revisit 4 bbl on a flathead

[kelly.ga]

This sounds like something I would like to do. I have a extra edelbrock in the garage, think it is a 650 cfm if memory serves me correct. Would that be too large for the 1947 flathead. Do you guys use some sort of adapter on the orginal intake or use one designed for a four barrel. My car has a alternator rather than a gen. No clearance problems I would think. Thanks

 

[Marv]

I do not know of a adapter for the original intake. Different companies like speedway sell a intake that fits the flathead and a 4 barrel will bolt on it. In my opinion a 650 is too big. Most people use a Holley 390 cfm. I am sure there are people on the Barn that knows more about this than myself. zmarv

 

[Chris Nelson]

Most of the manifolds available, llike Offenhaeuser, use the Carter base dimensions. Speedway sells an addapter that makes the Holley 390 fit. I have used a couple of these on flatheads and they work very nicely. Much easier to adjust than multiple carbs and do the same thing as multiple carbs when you step hard on the gas. I believe that there are manifolds available today that have the Holley base dimensions.

 

[Mike51Merc]

650 is too big.

 

[4t8v8]

I was running 2X2's on mine. Traded the 2X2 manifold for an Edelbrock 4 bbl intake. I had a new 650 cfm but couldn't get it to work right. Too much. Bit the bullet and bought a new 350 cfm. Built my own adapter from a 3/4" thick piece of aluminum plate.
Works great! I like it much better than the 2X2's. Every bit as much performance but much better mileage.

 

[ken ct]

Agree#3 toooo big.Need around 400 cmf. 390 is perfect. ken ct.

 

[kelly.ga]

Thanks guys, I was afraid of that, how ever, could I use smaller jets in the 650 and make it work ok. ???

 

[JWL]

The answer regarding smaller jets is a no. The "650" size description refers to the CFM of air volume the carb will pass at 1.5 inches. Whether or not a carb is "too big" will depend on the engine size and operating speed. Not jet size.

Using the 4150/4160 style Holley, on your car, can be a tight fit. Usually they need to be mounted backwards and a linkage provision made. Often a "riser" needs to be mounted, of about 2" heigth, to reduce interference at the water outlets in the heads. A better/easier choice can be the early Carter or Rochester or Holley Teapot.

 

[4dFord/SC]

Using the 4150/4160 style Holley, on your car, can be a tight fit. Usually they need to be mounted backwards and a linkage provision made. Often a "riser" needs to be mounted, of about 2" heigth, to reduce interference at the water outlets in the heads. A better/easier choice can be the early Carter or Rochester or Holley Teapot.

The Holley 390 in my '40 is indeed mounted backwards on a 1" phenolic spacer that lets it clear the generator back plate. Water hoses are not a problem. The stock accelerator linkage was slightly shortened, and there is no provision for the hand throttle. An added benefit of the spacer for me was that it allowed drilling and adding a vacuum supply port for the Columbia rear end, rather than using the wiper supply.

 

[Andy]

54 Buick WCFB on an Offy mani. Runs perfect.

 

[19Fordy]

390 Holley (backwards) on 8BA using 1 inch spacer. Made threaded aluminum coupler to adjust throttle. Stock 390 Holley comes with #51 jets.

 

[kelly.ga]

thank you all. I'm going to start looking for a used manifold and carb. Too much big bucks involved in this.

 

[jimTN]

If you have a 48 or earlier frame, be aware that some of the 49-53 4b manifolds have the carb mounted at a slant instead of flat like the earlier years. Have not found a wedge shaped adapter to convert them to same plane as the engine deck.

 

[jimTN]

While we are on this subject, what did the 390cfm originally come on. It appears the epay price is starting around 450+++++++++

 

[Fordors]

The 8007 Holley was developed as a performance carburetor. It sure uses many regular production pieces, nothing exotic, but it never had an OEM application. I'm sure it can be found cheaper.