74Runneer

Whats the best intake for my 318? mild cam, 1406 Edelbrock, headers, #302 heads. I have a single plane and want to get a dual plane for more low end power. Whats the best?

Silverick

Edelbrock Performer. Idle to 5,500....
http://www.summitracing.com/parts/EDL-2101/

74Runneer

Thats a chevy intake isnt it?

Silverick

Yes, it was! My bad. But, you knew what I meant!
http://www.summitracing.com/parts/EDL-2176/

74Runneer

Ha yeah i knew what you meant, too bad they $80 more for mopar.

78D200

Since you already have an Edelbrock carb, I'd recommend thier Performer intake as well. I ran the AMC version of what you have on an AMC 360 in a 74 J10 pickup and loved it.

440roadrunner

Add my name to the Performer list. My 360 recently developed a knock, and I scored a low miles stocker 318 about '72, with less than 40K. Never had the valve covers off. Plastic timing sprocket had NO wear.

In went the little mild cam, and the Performer/ 650 AFB. Snotty as hell!!!! Runs on regular gas!!!

74Runneer

What hp are you getting?

Gorts 5th

im running the edelbrock air gap rpm manifold 650 avs on my 318 i love it
ran the performer rpm on my old 318 got it in the shed don't know if i will ever use it again

Coronet 500

Whichever manifold you get I think it would be wise to have a working heat-crossover for your street car in your part of the country.

74Runneer

Why dont you use it anymore?

Whats a heat crossover?

Coronet 500

A heat-crossover is the passage that runs under the intake plenum allowing exhaust gas to flow through and heat it up to help with cold start and to atomize fuel for more even distribution to all cylinders.

The air gap raised plenum style manifolds don't have one making them more performance oriented. Theory is colder denser air with more fuel will make more power.

74Runneer

How do i make sure i have a working one? Is the normal lowrise performer a good suit? I only drive my car in the summer so 50 degrees would be the absolute lowest it will see.

440roadrunner

Frankly, I've taken a complete turnaround on heat crossovers. (I used to believe in keeping them functional) The heat crossover is the passage through the middle port in the heads which is hooked to the two middle exhaust ports, comes up through the manifold, and into the opposite head

Your "heat riser" butterfly and thermostat on one side of the car is CLOSED when cold, and forces a certain amount of exhaust to go up through that passage and out the other side, IE the butterfly "plugs up" one side of the exhaust, causing a pressure differential.

"Today's fuel" seems to be about as well off WITHOUT a heat crossover -- many guys have far more trouble with vapor lock and fuel boiling in the system and carb, than with the opposite end of the scale, IE a cold carb and carb icing or poor vaporization.

Many like to plug the heat crossover. I myself am running about a 3/8" heat insulator under the carb, which helped a bunch in my case.

Gorts 5th

the heat here in florida is sever i thought the air gap would hlp out the common heat issues for carbarated motors and its a single plain with a totally divided plenum
the performer is a great manifold dont get me wrong i don't need the heat riser here in florida
and i wanted to see wat type of performance i get with the air gap

I WILL MAKE A SPECIAL NOTE I USE TO GET CARB ICING ON MY 318 TWO BARREL BUT FLORIDA HAS VERY HUMID WINTERS WHICH ALLOW FOR THIS

78D200

Whenever I installed a new intake (Holley or Edelbrock - didn't matter), if it had the exhaust crossover port, I just installed the gasket the way it was, usually blocking it. After a certain amount of time the exhaust will burn through the gasket and travel from one side to the other. How soon will that happen? Depends on how often the motor is running, how hot the exhaust is, gasket quality and material, etc. The only way to make sure that it doesn't burn through is to either plug the heads or keep changing out the gaskets every so often.

If you do let the gasket block off the exhaust ports, that is perfectly fine, I'd suggest running a 1/2" phenoseal/plastic carb spacer between the carb and intake to help keep the fuel from boiling/vaporizing later on.

74Runneer

what else do spacers do?

78D200

There are a few different styles out there, 4 hole, 2 hole, single. From what I was told by a local speed shop, the 4 hole is ideal for low end power, 2 hole is designed more for normal street driving, single is great for street/strip (I could be wrong - please correct me if I am).

The height of the spacer also plays a part in that as you can get them anywhere from 3/8" up to 2" thick. What the height will do for you I am unsure about.

Gorts 5th

I know some intake or carb manufacturers suggest what type of spacer to use 4 hole 2 1 my carb 650 edel avs says i should use a 4 hole
so that the engine doesn't loos its performance
i haven't run one on this new set up but on my old manifold i used a 1 inch spacer for heat insulation from carb