Changing a B intake for better flow

[Hivolt5.0]

This write up and pictures are from Ole Don.

"We would all like to be flush with extra cash to buy toys. Often what you have is what you will use. If the subject is a stock cast intake for a street driven car, this is just the ticket.

Give me no credit, this is copied from an article by John Mummert about fifteen years ago.

Clean the intake, and place a new four barrel gasket on a stud or two to locate it. Scribe around the inside of the four holes. I have a die grinder now, the first one I did with a Dremmel and sanding drums. First, open up the four holes to the scribed lines. They get very close to the edge of the casting. Dont worry, we fix that later. Then, open up the divided part front to rear but not side to side. Clean it up nice, and take some metal out where the holes turn into the runners. Then, clean up the heat transfer area with carb cleaner and a wire tooth brush. After is all the way dry, lay in a gob of epoxy, level it, and give it 24 hours to cure. File it flat being carfull to not take any metal off the sides, just take the epoxy.

This made a huge improvement in mid range power on my nearly stock 312. I used a 500 Edelbrock on a four hole two inch spacer. I was very happy with the results.

Good luck, Don"

 

[GREENBIRD56]

There is one further suggestion - comes from the Dyno testing of Ted Eaton. Try modifying the carb spacer you fit under the throttle plate to direct the flow out of the venturies a bit. His testing showed that a four hole spacer that has the forward bores tapered to the rear and the rear bores tapered to the front has an advantage over simply leaving a round vertical exit into the slot. His write-up doesn't delve into the why - but I believe it is due to the way the butterflies open. With the carb in hand to see the lower plane - the primary plates swing down and direct flow rearward across the edge of the throttle bores - and then still further down when fitted to a round tube opening. The taper must smooth the exit path - and guide the airflow a bit to ease turbulence. Same must apply to the secondary throttle which is a mirror of the primary.

 

[Ole Don]

That is correct Greenbird. There are spacers available now with that feature. They are about ten times more money, and on the street one may not notice the difference. I did run one two years at Bonneville where every little bit amounts to a big advance.

 

[Talkwrench]

Try an Edelbrock 2 hole spacer 8714 as you have created , you may need the intermediate plate as well 2732.