X heads vs Eddies

[340rt]

I have a 340 with an Extreme Energy 268 cam and auto trans.
I pulled my X heads (mildly ported) and I found exhaust valve recession ranging from mild to severe (after 80 K miles). My first reaction was getting rid of my X heads and go for a set of 6077 Eddie heads ,however due to the fact that I'm on a tight budget I've been thinking of getting my X heads repaired with hardened exhaust seats and SS exhaust valves.One thing that bothers me is that I won't have the advantage of the closed chambers the Eddies have. My question is how big a difference will it make using my mildly ported X heads as opposed the the eddie heads for my application .
Your advise will be greatly appreciated. Thanks in advance.

[RoadRaceJosh]

If all you need are hard seats then I would have them installed in your heads. You should be able to repair what you have for 1/4 the cost of the Edelbrock heads. Unless you have domes that stick up .045-.060" on your pistons you give up the prime benifit of closed chamber heads anyway.

[rumblefish360]

You'll be ahead of the game with the X heads in my opiniopn. The Edel. heads are nice, but only out flow stock X heads by a bit if the Edel. flow numbers are correct.
A pocket ported set of X heads should flow as much if not more than the Edel. heads out of the box.
The gain in compresion is offset by the metal used, aluminum, due to the higher rate it will ride the heat from the engine and itself.
The only advantage of the Edel. head in design is the closed chamber design when used with a flat top (Near or @) zero deck piston for a excellent quench effect.
The upgrades you put into a X head are worth while.

The best thing about the Edel. heads is the overall package of equipment it comes with along with well flowing ports. The price is very attractive vs. spending on the repair of iron heads. Even more so if it is going to be a Major repair.

[340rt]

I'm using flat top pistons , .012" above deck.

[pishta]

They sell an open chamber Edelbrock head for the 340 pop up piston, I think its called the RPM340. I would look into a set of Econo W2's and a thick head gasket. How much are the seats and valves going to run? I got $550 for my set of good X's on Ebay. Even the Commando or RT heads are a great head, just check lifters for an oil hole (AMC style or most aftermarket) and use oiler pushrods.

[perfmachst]

hello, use the X heads. when you have valve grind , grind valve and seat at same angle. this will prevent hammering of the seats/valves. just food for thought. ps. the X head does out flow "eddys".

[dave571]

fairly mild cam etc. I don't think you would see any benefit from the eddys.

A valve and seat job is a lot cheaper.

[BDS 871 Cuda]

I think the X head is the same as the J head.
J head flow 200 cfm as cast and 264 max ported.
Eddy RPM flow 243 out of the box and 293 ported.
Talk to Ryan at www.shadydellspeedshop.com
He will give the best advice.

[DartGT66]

I agree, talk to Ryan. He has seen and tweakwed all the SB combos and does not purposely pull you in to any direction, a honest guy.

[Slingshot383]

By the time you add cost of valves, hardened seats, installation and cutting of seats, guides?, seals, setting the springs, you've spent nearly the same money on 35+ year old heads as you would on a brand new set of heads. Yes, total flow is about the same between the heads, but look at flow throught the lift curve, you may be suprised at what the Edelbrocks give you. There is also the weight savings, and the fact that you can open them up even more later.

[SixGunner]

Not only the weight, but with aluminum heads you can go a touch higher on compression too, because the aluminum will help dissipate the heat. I've got some on the .020 over 360 in my 300, with KB107's that spec out to just under 11:1. And it runs fine on 92, and even 89. I don't have the berries to try 87 yet though!

But they are pricey. I got mine 5 years ago for a birthday gift (thanks Dad!) and even then they were $1200.

One of these days, I'd like to swap the heads on my truck (2.02 early 340's) onto the 300 engine and see if there is any real difference. But I don't feel like torquing 4 heads, or 6 if you count the retorque on the Eddies.

If you're bux down, stick with what ya got and fix em. JMHO.

Jay