D8 or EO

[ski4evr]

I found some heads to get rebuilt from a place in CA. A D8 and an E0. Which one should I go with? They both have the same valve sizes and carb throats, but the E0 is possibly a hex head with a larger intake volume (1420 cc) while the D8 is flat with a smaller intake volume (1345 cc). The flat top log seems easier to modify for a direct mount. Yet, I've seen a few hex heads in this forum modified for a direct mount. Does an intake volume difference of 74 cc's make a difference?

ski

 

[ski4evr]

Forgot... The shop in CA said they could mill the head down to 48 cc's. Is this enough to offset the compression change? The head will be going on a stock '68 block with new head gaskets.

ski

 

[CZLN6]

Howdy Ski:

THe choice is really yours and what you, ultimately want to achieve.

The EO head has a slightly larger capacity intake tract. That will only matter at higher rpms and could slightly hurt low end performance by reducing velocity.

The D8 flat-top log is an advantage in converting to a direct mounted two barrel, or multi carbs.

Either head will have several advantages over your current '66 head casting.

Shipping a head from CA to CT is going to be a fairly large expense that I'd rather see you put into your car. Is your car an auto trans? what is your CR goal? What head gasket are you going to use to install the new head?

Both of these heads should have a chamber volume of aprox 62 cc's. Milling .010" will reduce the volume by aproximately 2 cc's. Measure, to be certain, of what you have to begin with. Read the sticky at the top of this forum for details on chamber and head gasket differences.

Can you specify a three angle valve job and back cut intake valves? These are relatively cheap machining steps that do improve the performance of any head.

Let's hear from you.

Adios, David

 

[ski4evr]

I spoke with the shop this morning. I'm going to go with the D8BE-6090-BA head. The shop will mill it to 46cc's. This should compensate for the deck height of the '68 block and a composite head gasket. It will be a three angle valve job with hardened seats. I also requested a 30 degree back cut on the intake valves and the shop said not a problem.

I have a c4 transmission.

My compression goal is 9.2:1 to 9.5:1. The 46 cc chamber should achieve this.

The flat top head is important - for direct mounting - since this is what I intend to do. Also, I want to keep the low end torque up. I don't plan on doing long highway trips or WOT runs with it.

I have a Weber 38/38 that I plan on direct mounting. I believe it is rated @ 370 cfm (based on previous posts in this forum). So, a little more than the Holley 350, but not as wild as the Holley 500.

Sound good?

ski