Re: Edmunds Intake

Posted by Anthony Pallett On 2013/5/13 0:33:25

Overall impressions are pretty good. As way as vintage speed equipment goes its not a bad design, I have seen far worse over the years.
Keep in mind Edmunds from what I understand was a more "low end" performance company (in regards to their contemporary's many of who are still in business) and tended to be a one size fits all design so this intake to a comparable L8, Buick, Olds, Pontiac, Edmunds intake is likely very similar.
The heads they produced all had an identical combustion chamber style not saying that is a bad thing just the nature of the company.
It is a LOT heavier than I expected, not near as heavy as a cast iron intake but I was suprised. The top of mine was polished at one point but the bottom was left as cast. I don't know if this was done by Edmunds or a previous owner.
The ports are fairly roughly cast and I don't see any evidence of previous porting but it seems there is enough meat to do some light polishing if you wanted but their are some blind corners, specifically the front and rear runners so unless you went with extrude honing would never get it all smooth.

OK now the meat and potatoes part
The ports are round just like the ports in the block and measure 1 5/8 diameter.

The carbs are 6 1/2 inches apart as measured center to center on the opening for the butterflies.

The holes for the butterflies are 1 3/8 inches.

The floor of the manifold is stepped, not like a dual plane intake but the plenum seems to be on the same level but it steps down as it goes into the runners.

From the carb mounting flange to the highest point on the floor of the intake varies from 3 3/8 to 3 1/2 I think this is due to some fairly rough casting.

The lower portion seems to be about 4-4 1/8 deep but its difficult to get a good measurement.

the preheating line that looks as though it would tap into the cars heater line is 1/2 inch inside diameter and it only runs along the outside of the the intake.

The plenum seems to be divided from left to right as in the drivers side carb venturi feed the 3,4,5,6 cylinders and the passenger side venturis feed the 1,2,7,8 cylinders.

The inner runners (3,4,5,6) look as though they should tie into the outer (1,2,7,8) but using a flash light with the lights off I cant see any light coming out of the outer runners. The intake is still in its as delivered state so maybe their is some blockage in the ports.

The front and rear runners are close to 13 inches long from the center of the carb flange to the end of the port as measured outside the intake. My tape measure (the best of all calibrated instruments) will go all the way through the ports on the outside and the measurement is pretty close to the same

The inner runners are a straight shot from the plenum under the carb and are 4 5/8 inches from the end of the port to the center of the venturi and 5 1/2 inches to the divider in the plenum.

There is what seems to be original 1/2 inch "vacuum" line in the riser under the rear carb mine has a pipe plug in it and I don't know that I will be able to get it out easily. and it has another one on the forward runner 3/8 inch in diameter just forward of the "Edmunds" script. I have never seen one here in any of the pictures I have seen of these and may have been added instead of potentially damaging the intake by removing the old pipe plug.

Those are pretty much all the hard numbers I can think of I'll upload some pictures as well to show the step in the plenum and some of the more interesting points. If any more information is needed let me know and I'll get it for you.

Once I get it cleaned up I'll try to get some flow numbers compared to a stock 2bbl intake to see if it flows better than a stock piece, my guess is it will be a good bit better the plenum are is pretty generous and the carbs mount fairly high, I would almost compare it to a "medium" riser tunnel ram (you might need to be patient for this I'm building, slowly an inexpensive flow bench).