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Last Update 04-04-08



By now you've heard of KRE's new aluminum D-port heads that are made with the original factory D-port

shaped exhaust ports. Their thinking was - if someone didn't want to buy new headers to use with the Edlebrock heads, which require

the round port headers or round port factory exhaust like Ram Air Restorations sells, they could save money.

This is the second set of these heads that have come thru my shop. I know that hurried production schedules may cause

a lack of deburring necessary before using the heads, I can deal with that, but I still can't wrap my head around what we're seeing design-wise.

The heads come in with all of the water jackets taped shut - so the aluminum chips don't fall out.

What ever happened to a few seconds with the air gun and a deburr tool?

Oh well, it's just me. Must have been in a hurry. Twice.

Moving on - the unfinished heads look like this:

You'll need to look closely at all machined surfaces, as they will need deburred.

You can see the sprark plug hole needs deburred too.

You'll need to blend the step that appears here outside the seat at the noon position.

You can see how we finished the step, and the bowl.

One of the good designs of this head are the short guides and the position of the spark plug.

My template for the standard intake opening for my Edelbrock heads compares as:

eek - It's impossible to open the intake ports like our Edelbrocks

without completely exposing the pushrod hole. Placing a tube in there is moot.

You still have the restriction. So,....I decided to merely straighten the sides

and raise the roof a little.

Upside down view - see the guides?

Finished intakes.

The exhaust were quite a challenge. Here's what a stock Fel-Pro

header gasket looked like against their exhaust port opening.

Right side up view - the thumb screws are precision made with locator steps.

No hocus-pocus.

upside down view

Their ports are very, very small compared to a stock 1424 Fel-Pro gasket.

No need to scribe the floor. (If you know what you're doing.)



Head bolt spot face missing. Need to spot face it.

Also notice how far off the concentricity is for the head bolt boss. All of them are like this one.

We move onto the oil drain back holes and their position under the edge of the spring seats.


You see the spring seat overlaps the oil drain back hole, leaving

an incomplete diameter and a thin spot with sharp edges that need deburred.

Here's what the Edelbrock area looks like. Drain-back hole is distanced from the spring seat to avoid

the KRE design oddness. Also notice the heli-coils for the rocker studs.

The KRE heads do not have these. It's a strength and wear consideration. In fact, their threads begin

almost a .150 thou. down from the top, crutching important thread engagement in this very important high stress area..

Roller spring pressures? Not me.

They also do not install heli-coils for the exhaust bolts. Edelbrock knows this is a must and include them.

All of this extra work and they cost the same as a pair of Edelbrocks.

I do like this part of their design. The spark plug is pointed towards the exhaust port.

I'm not sure why they didn't go all of the way and tilt it even further like the known good brand X's.

They could have. So could Edelbrock.

FLOW numbers....

As you ought to know by now, I never talk flow numbers. Why? Because you don't know how to relate to them,

and it's 100% facetious to talk about them when all you ask is. "What do they flow" and you're ok hearing one peak number.

That's ignorance in action -and all of the Pontiac magazines are guilty of not educating you any better.

Pontiac salesmen that talk "flow numbers" leave themselves open for lawsuits as far as I'm concerned.

KRE claims their heads can "flow 260 CFM" out of the box. Call them and let them explain that statement.

Their heads were flowed at an independent testing facility on the west coast, having NO affiliation with me or my company.

Peak flow on these heads out of the box, on a SuperFlow 600, with a standard valve job, was 222 cfm.

Afterwards I was asked to flow them on my polygraph machine - which is one of three FlowData Laminar Flow Element benches

designed by Rick Blood, which are the same as the TWO benches Warren Johnson owns, peaked flowed at .500 lift at

197 cfm.

I have yet to flow them after our upgrades. The owner of these heads only wants a 500 hp 455 street engine. I feel the work we did

to the heads coupled with one of my cams will give us that power. In a couple of weeks I'll post the results. After the extra necessary work, and the obvious inability

of the heads to deliver the power as a well ported set of our Edelbrocks which still sell for only $2500 dollars. I don't get the "savings."

$2500 plus a sert of round port headers or cast iron exhaust manifolds is approx. $3000. I charge $3500 for the finish work on these KRE heads just to get them

ready to use.


Flow data = numbers increased.

These numbers are the gain made over the stock port - which as you know - are sold as "260 cfm" heads.

Using a stock Edelborck 2.11 diameter intake valve and a standard 45 degree valve job, our porting upgrades made

little difference at .100, .200, and 300 lift. However, at .400 lift the stock valve picked up 8 cfm, and at .500 lift

it picked up 24 cfm over the out-of-the-box heads. Experience told me that a better valve job

and better valves would pick up the numbers. It did. Using the same intake valve I use on

all of my Edelbrock heads, (2.11 dia.) there was a much bigger increase over the original untouched port.

At .050 lift there was a 4 cfm gain. Same for .100 lift.

At .200 lift it picked up 6 cfm.

At .300 lift it picked up 8 cfm.

At .400 lift it picked up 18 cfm.

And at .500 lift it picked up 31 cfm.

At .600 and .700 lifts it was the same as .500.

Real world peak flow after upgrades...........

In the world of absolute accuracy - the corrected peak flow number from the improved port and better valve is:

228 cfm.

Clck here to see Westechs test of another set of KRE 's that came thru here last summer.