Carb question

[Farmstore34]

Howdy all,
my "new" 70 K20 has a 350 with an edelbrock intake and a Carter AFB on it. The intake is the spreadbore design like a stock 4bbl chevy intake, and the carb is bolted directly to it. My questions are:
1- Isn't there supposed to be an adapter plate under that type of carb when used on the spreadbore intake?
2- would using a spacer plate under the carb give me any improvements?
I'm overhauling the carb right now (cruddy gas tank from sitting) and looking to see what else I can do while its out. Thanks!
CLT.

[redhead69]

Which edelbrock intake is it with a spread bore?

[Farmstore34]

I'll have to check which model. I think its the basic Performer model.

[Chevyholic]

Originally Posted by Farmstore34

Howdy all,
my "new" 70 K20 has a 350 with an edelbrock intake and a Carter AFB on it. The intake is the spreadbore design like a stock 4bbl chevy intake, and the carb is bolted directly to it. My questions are:
1- Isn't there supposed to be an adapter plate under that type of carb when used on the spreadbore intake?
2- would using a spacer plate under the carb give me any improvements?
I'm overhauling the carb right now (cruddy gas tank from sitting) and looking to see what else I can do while its out. Thanks!
CLT.

I would think a phenolic spacer would help keep the fuel away from the heat a bit, leaving less chance for the fuel to vaporize. Most auto parts stores carry them and the one's I've seen lately are universal, meaning they have gaskets for spread and square bore.

Good luck!

[brak]

EXCEPT, make sure you get the spacer with 4 round holes as opposed to one big opening. that carb (and any edelbrock) will run like crap if you use the open plenum.

I always use the Edelbrock #8711

[bigpig72CST]

What is the difference between using the open plenum generic, and the Edelbrock that you have pictured? I just bought the el-cheapo open plenum when I put my Edelbrock carb on, and it seems to work ok. If it will run better for some reason, I am all for swapping.

[bryanw1968]

Originally Posted by bigpig72CST

What is the difference between using the open plenum generic, and the Edelbrock that you have pictured? I just bought the el-cheapo open plenum when I put my Edelbrock carb on, and it seems to work ok. If it will run better for some reason, I am all for swapping.

The adapter with the four holes will make more torque than the open plenum.
Also, a spacer will give you a few hundred more RPM's on the big end.

[Farmstore34]

Just finished the overhaul on the Carter AFB on my 350, runs so much better. Idles without dying, runs much smoother and has better power. Carb was full of crud.
I ended up not using a spacer or carb adapter on the advice of my parts guy. I'll spend the $20 on the brakes instead!
CLT.

[brak]

Originally Posted by bigpig72CST

What is the difference between using the open plenum generic, and the Edelbrock that you have pictured? I just bought the el-cheapo open plenum when I put my Edelbrock carb on, and it seems to work ok. If it will run better for some reason, I am all for swapping.

I take that back, as I have double checked my documentation. The open plenum is only an issue when using an edelbrock carb adapted to a quadrajet intake.

I just remembered the explicit "do not use an open adapter" in the instructions, so over the last 10 years i have avoided the open spacers, for no good reason.

oh well no harm, no foul

[raoul.duke]

http://www.hotrod.com/techarticles/carburetor_spacers/

interesting info (esp. regarding the rejetting). seems that the other posts on the board shows that everyone is *almost* unanimously in favor of spacers......

[martinkh]

A spacer that doesn't maintain the plenum split would be like going from a performer to a performer RPM manifold. Don't use it if off-idle is the most important thing. Also, the Performer a universal mount, both spread and square bore will seal.