I was putting together a 400 and I got some aussie heads I was going to use. The pistons are stock dished pistons. Just wondering what cam I should use? I have a edelbrock performer intake , quadrajet carb, and doug thorley fenderwell headers. This was going in my 78 bronco. Just want something with good low to mid rpm torque,power and wont hurt mpg. I have been searching in this forum and havent seen too many suggestions for this combo.
Thanks
Tom

 

You can't get 'good low to mid rpm torque,power and wont hurt mpg' with Aussie heads on a 400 and run on 93 Octane fuel.

You need a cam with no less than 60 degrees ABDC Intake Valve Closing angle. A cam like this will not have 'good low to mid rpm torque,power and wont hurt mpg'.

Someone on this forum is using an Edelbrock #2172 cam which has a 68 degree ABDC IVC in a setup similar to yours. it will run on 93 Octane, but that will not meet your criteria.

There are other cams available that I like better than the Edelbrock, which have an IVC of 60 degrees ABDC or later, but the low rpm torque and MPG will suffer as well.

If you are willing to give up some low end torque and some MPG, I can suggest some good cams that you can use.

 

TDG,

I am using the Edelbrock #2171 with Aussies (check my gallery)...I do NOT have a stall converter, and my car (4400 LBS) does NOT have really good torque until 2500 RPM or so. 3000-4000 it is a monster, but driving in that RPM range obviously destroys gas mileage. It will barely spin the tires (will do so if I hold the brakes)...the other issue on my vehicle is the rear end is geared for highway cruising - so on the low end, I do not know if that cam would suit your needs in a truck (ie do you mud bog, pull, etc, or just dirve around town).

Edelbrock has some computer data if you call them concerning Aussie heads, so they can tell you what to expect with their two cam offerings. Most guys seem to prefer Comp Cams on this forum with flattops and stock heads; the problem with Aussies is that the compression is so high (static) that it requires a cam with specs that give a reasonable dynamic compression, and that narrows your choices down if you want to use pump gas. Mine does run on premium, but it doesn't like anything with lower octane. I get 14 MPG average (but again, it is a 4400 LB car, not a truck).

I am sure you can find a cam that will work to give the desired torque and HP, but you are going to have to pay for that in gas.

I'd call comp cams as well and talk to their techs.

Best Regards,

DiMora

 

I didnt realize the static cr is so much higher with the aussie heads with dished pistons. I thought it was about the same as stock heads with flat top pistons. But then again now that I give it another look I guess the volume of the dish on the pistons is much less than the volume of the combustion chamber of the stock heads.

i think i will stay with the stock heads.

thanks

Tom

 

Stock heads are 78.4cc, while Aussies are 59cc. That is almost 20cc difference. The dish in a stock piston is about 10cc. You can use stock heads with a Badger flattop piston, and you will have 9.0:1 CR. You could also use a Cleveland KB148 piston by bushing the rod to take the Cleveland pin. This will get your CR up to about 9.5:1. With this CR you could use a cam with about 260 degree duration. A Crane H260-2, or Comp Cams 265DEH. A Comp Cams 255 DEH will give you great low end torque, but I would not recommend it with more than 9.1:1 CR.