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slowbird · 07-15-2004, 12:07 PM

Cliff: do you have the flow numbers for both heads at all the lift points? Also what was the average HP and TQ for the iron heads and the KRE heads and what was the rpm range?

Larry Navarro · 07-15-2004, 04:56 AM

Darrel,
my iron-D heads flow 277cfm @ .550".
Sure thats alot of flow but the KRE-D's most likely have better low lift numbers than mine, plus less weight.
My heads are more suited to a high rpm motor for a car with a lower set of gears and less weight.

71 formula · 08-02-2004, 11:58 AM

Sound like your combo would have been better with e heads.

Mo · 07-21-2004, 10:22 PM

Thanks Cliff/KRE for the hard work and effort. Wish you could have put a different cam to match the KRE heads while on dyno. Do you think it would have made much difference? Also have you seen any forced induction motors using these heads yet?

Larry Navarro · 07-14-2004, 08:45 PM

Thanks for the info Cliff.
Most likely going "KRE-D" for my next engine!

Z Code 400 · 08-09-2004, 10:30 PM

Impressive!!!...Robert

thunder1 · 07-22-2004, 04:55 PM

Dude, we need to talk! Competition is where it's at!! Is that Dave I see in my rear mirror?? Rick

Armadillo · 07-30-2004, 03:50 PM

Cliff,

Do you have the seperate cooling lines from the water cross over going to the back of the KRE's?

Tom

PONTIAC DUDE · 07-15-2004, 10:43 AM

Brian. there are others. Check with Dave Underwood. He is the dude that won the KRE heads at VMP.

He changed just the heads.

Cliff R · 07-15-2004, 12:16 PM

Lloyd, LOTS of things going on at KRE. I will not provide any info unless they approve it first...sorry....Cliff

Cliff R · 07-15-2004, 12:43 PM

The 6X heads flowed intake/exhaust: .100/88/85, .200/153/122, .300/206/164, .400221/185, .500/232/196. The KRE heads flowed: .100/92/71, .200/166/129, .300/234/169, .400/256/201, .500/261/220.

Average HP/TQ iron heads: 490.7/422.1
Average HP/TQ KRE heads: 525.3/452.5.
Peak HP/TQ iron heads: 5300/3900rpm
Peak HP/TQ KRE heads: 5600/3600rpm

Don't be misled by where the peak tq occurred at with either combo, the numbers start out right at peak at 3500rpm and stay steady or flat till 4300rpm, still making over 500 ft lbs with the KRE heads to 5100rpm and to 4700rpm with the iron heads.....Cliff

Herb Hagan · 08-09-2004, 07:55 PM

Congratulations Cliff, nice job!! Good talking to you and look forward to seeing you next year.

Herb

Brian Baker · 07-15-2004, 07:50 AM

I'd also like to add that, to the best of my knowledge, this is the first time anyone has done a "back to back" test of iron heads and aluminum heads, where the only thing changed were the heads, and the figures posted.

That's what alot of you "tire kickers" have been wanting, right?

Kudos to KRE and Cliff.

Cliff R · 07-15-2004, 08:23 AM

Brian, that is EXACTLY why KRE wanted to do the test. They already have numbers on a couple of combo's....but....the ONLY way to really know how these heads are going to work is to add a set on an existing combination and change NOTHING else. My combo was chosen because I'm close by and have very good numbers on the car. A couple of weeks ago I made 6 back to back runs without shutting off the engine and all runs were between 7.71 and 7.78 right at 90mph. The increased power should be pretty easy to pick up by the timeslips.

To be perfectly honest I was a bit surprised by the power my engine produced with the iron heads and iron intake/q-jet. My intake is modified at the flange to accept both square and spread bore carbs, but very little material removed in the runners. Even so KRE was convinced it would not make power past about 5100rpm. Remarkably it pulled right past 5500rpm with their heads (495hp @ 5600rpm) and made peak power at 5300rpm with the iron heads...and....only fell off a few hp at 5500rpm.

We're headed to the GTOAA even this weekend, will get to the track ASAP to back up the numbers......Cliff

KS circutguy · 07-14-2004, 11:15 PM

Cliff,
How about re-testing the same combo, but trying a set of E-heads?
Thanks,
Steve

Cliff R · 07-15-2004, 03:18 AM

"Maybe I am way off here, but couldnt you have a set of 6x-4's ported to 260 and come up close to those same numbers? That would save allot of bills wouldnt it?" Darrell, no doubt they could port my 6X heads pretty hard, cut them for more compression and get closer numbers. I don't think KRE's intension is to port iron heads to run with their new heads!

"Cliff,
How about re-testing the same combo, but trying a set of E-heads?
Thanks,
Steve "

Steve, we've already tested that combo except we used the RPM and T-II intakes, not my iron intake. I posted the info some time ago when we tested the first 455 with KRE's new heads. The E head engine made 505hp/551tq peak power using a Demon 850 and T-II intake, and was down a bit at lower rpm in comparison to the KRE heads.

"Are your 6X's stock, or ported?" My 6X heads are very mildly ported. No porting done under the valves other that running my bowl hog into the bowls then blending the result into the port. I opened them up a bit at the pushrod bulges, ground out the smog bumps and removed any casting flash and smoothed any sharp edges. They made pretty good numbers considering the small amount of work done to them.......Cliff

PONTIAC DUDE · 07-22-2004, 04:10 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by thunder1:
I am Rick not Dave, I am impressed with the KRE's so far . I adjusted the jetting and dropped the timing and had a notable improvement ! In fact I fragged the trans on I-20 doing a test and tune. Understand that when I talked to Jeff Kauffman , my shift points were at 5000 rpm. My new shift points are now at 5700. This created a noticeable increase. The heads are breathing much better. We'll see how it all works out at Norwalk on thursday and friday for test and tune. <HR></BLOCKQUOTE>

Rick.... Take that T-350 out and install a T-400. LOL.

Dave said if ya start getting close,

he's buying a Dude 511 cu.in. Street Crate Engine. Bwahahahahaha.

Cliff R · 07-19-2004, 04:18 PM

We are getting ready for the second round of the testing. The engine is back in place and ready to fire except one header was cracked at a weld so it's out for repairs. I've kept pretty close records on the old combo and will be able to see any benefits from the new heads at the track.

I think that this test is very realistic. Most of us spend some time with our iron "D" port heads in terms of good valve/seat work and minor porting. As in the case with my 6X heads, they have very little material removed from them, but excellent bowl/valve/seat work. I don't think it is or would be practical to port them to near 260cfm for my particular application. I do not have a flow bench or access to one. It is my opinion, that for the vast majority of hobbyists, the level of porting required to obtain 260-270cfm from iron "D" port heads requires a flow bench to not only maintain consistancy but to insure the minimal amount of material is removed in the right places. With the KRE heads, we get heads with very conservative runner volume, a nice straight intake port and an excellent combustion chamber. The results we are seeing from this testing is very typical of what nearly anyone would see with a "mild" street/strip engine. In my particular case, we made 40 hp right out of the box with no other changes. We'll know in a few days if this is going to improve actual vehicle performance. My guess is about .2 to .3 and about 2 more mph.....Cliff

Cliff R · 07-31-2004, 12:15 PM

Just running the stock heater hose fitting in the passengers side head........Cliff

Brian Baker · 07-15-2004, 11:51 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by PONTIAC DUDE:
Brian. there are others. Check with Dave Underwood. He is the dude that won the KRE heads at VMP.

He changed just the heads.

<HR></BLOCKQUOTE>

Did Dave do any back to back testing (on dyno or on track)?

If so, has he posted the results?

Where can I find them?

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