I had a chat with a guy who does cam Doctor work. He was asking me about the cfm of the intake and heads. I'm planning a rebuild on my 292, and I'm just in the process of gathering parts and info. Mummert has a head flow chart based on the heads with 1.92 intakes. I however, have heads with 1.78 intakes. I didn't find any info on them.
Another issue is the carb. I'm not sure if I can do any better. I've got on the shelf a couple motorcraft carbs. One has a 1,14 venture, the other has 1.21.
The existing carb on the truck is a holley with a ford tag. BBT OGA U
Can anyone tell me about that carb?

 

Welcome to Mike's Carburetor Parts - Your Number 1 Carburetor Parts Store There are pages that list by tag number if you want to do some searching

 

Jim
Thanks for that link. According to that site, my carb is stock to that engine. It was also used on 352, 360 and 390. So it must definetly have enough flow for my needs.

 

A '57 or newer single carb stock intake flows about 174cfm
Mummert's chart shows a plateau at about 170cfm for ECZ-G heads, which are just about the best flowing stock castings.
So 170cfm can be considered a best case scenario for unmodified factory castings.

Further info:
'54. '55, and '56 intakes will flow less because they have smaller ports and and not as good a design overall.

5752-113 and 5750-471 heads will flow slightly better because they have larger chambers, unshrouding the valves. Any other head will flow less than the 3 mentioned here.

A bad intake will drag a good head down. For example, a '56 intake might limit flow to 150cfm, even with G heads.

An excellent intake will maximize the flow of a good head, to a point. For example, an aftermarket 4-barrel intake (260+cfm) used with stock G-heads will probably achieve that 170cfm figure whereas the factory '57 4 barrel intake may actually result in a slightly reduced flow from the 170cfm figure.

 

Yes, I've seen that chart. It's great info. My heads have the 1.78 intakes. Mummerts chart is based on the 1.92 intake valve. It's amazing on the exhaust side the amount of flow increase going to a 1.60 exhaust. That's on a street port with .450 lift.
On the stock ports the intake flow between .450 lift and .500 lift is nothing. A difference of one.
My engine currently in the truck is a 62. So, hopefully it isn't a restricted flow unit. I know the carb has plenty of flow.
The question of flow was brought up to me by a cam doctor guy who's here locally.

 

The flow rating on any carb is really misleading. Its based on a set parameter . 2 bbls are rated at 3 inches of mercury. If the engine pulls a vacuum higher than that, the carb will flow more. The smaller carb will perform better at lower RPMs, the bigger in the upper RPMS