Which edelbrock heads to buy for my 340?

[wart1de]

Hey guys and gals

I've got a 340 which I plan to run Eddy heads on. It'll be a EFI stroker which i'm aiming for anything over 400hp at the flywheel. I've read a few comments here that these heads don't really have enough compression for an alloy head. Do I need to buy the slightly more expensive 340 specific Eddy head or am I better off with the 360 version because it will give more compression?

 

[Chryco Psycho]

depends what piston you have in the engine , stock 68-71 340 pistons actually came above the block by a few thou so the heads are relieved to accomadate this so using the 360 could cause clearance issues

[wart1de]

I havn't actually bought the crank/rods/pistons yet, I was going to leave those parts up to the engine builder. The AU dollar is high at the moment so I figured I should buy the heads now to save money. I just don't know which to get.

Would the typical stroker piston in my application be likely to go above the block? It is a street car running pump fuel which is available up to 98 octane here. Not sure what compression I should be running or how tall the piston will be to achieve that.

[Chryco Psycho]

you can have a custom piston made to get exactly the compression you want , basically the 340 was close to 10:1 which would be awesome with 98 octane fuel available , the problem with the alum heads is you need around 11: to retain the same heat in the combustion chamber as 10:1 with iron heads so the piston will end up having some kind of dome on it

[wart1de]

If you were building it, which version of Eddy head would you use? It is a complete ground up rebuild. Only thing to survive will be the block.

[Chryco Psycho]

use the non relieved head & have a custom piston made to fit , I would have the piston .005 below deck & use a .035 thick Cometic MLS gasket

[wart1de]

Standard head it is!

Thanks Chryco, you da man.. Let me know if you are planning any trips down under so I can get you to build me an engine while your here

 

[Chryco Psycho]

I have always wanted to see Australia so I guess I should drop by & help   

[aussie-e-body]

I have always wanted to see Australia so I guess I should drop by & help   

drop by my place while your at it.i need my 440 built.
what state are you in wart1de?

[moper]

A lot depends on what you're doing.  Diamond p/n 51007 flat top at 0 deck with Edelbrock 60779 is 11.8:1. High for a street car of any kind that may need to run pump fuel. (at least in the US)

Diamond p/n 51409 and same 60779 is 11.3:1 at 0 deck. With the right cam, definately usable on 93 octane pump fuel.

Diamond p/n 51411 and same 60779 is 10.1:1 at 0 deck. (they have a larger 21cc dish as opposed to the 10cc dish) Safe for all fuel octanes.

All are set up with .040" or so quench. To run the MLS gaskets, you must have the block and heads surfaces cut to get the proper very smooth surface. Otherwise they will leak permanently. (i say that because they do sometimes leak until the engine has been heat cycled a few times...)


War..you have mail...

[wart1de]

drop by my place while your at it.i need my 440 built.
what state are you in wart1de?

I'm in Queensland. How bout you?

[aussie-e-body]

I'm in Queensland. How bout you?

im in WA mate,in the south west-sheep country

[wart1de]

Wow. Thats a loooooooooooooong way away from Brisbane

There seems to be a good percentage of Mopars in WA compared to QLD. I saw photos of a WA Chrysler show years ago and couldn't believe how many 'Cudas were there.

[aussie-e-body]

mate,theres some serious mopar muscle around here.the next town down the road has a hemi charger and 3 six pack ebods and 1 of them is the original FOX 1-population 4000.,.more scattered around the south west.were taking over.WE WILL RULE THE WASTLANDS

[wart1de]

FOX as in the Challenger from Running On Empty? I sort of knew one of the previous owners who had it for a few years. He was the one that restored it and had it in Street Machine mag. I remember when he first bought it - it was running terrible and he pulled up at our hang out spot. Knowing what the car was we all quickly paraded around it while he pop'd the bonet. Engine bay was dirty and there was fuel leaking out of the centre carb. 

After that he tried to do a burnout and the thing just coughed and stalled. Wasn't a good first impression infront of the Holden boys.

It's come along way since then.