Jeff Kauffman called a few weeks ago and asked if I would be interested in doing some direct testing with his new aluminum "D" port heads. The first part of the testing would involve removing the engine from my Ventura and taking it to KRE for some dyno runs. Then, swapping out the 6X heads for a set of KRE's new heads, 85cc CNC chambers (unported). The second part of the testing would involve some dragstrip runs to see how much if any the new heads improved track performance.
I thought about it for about a milli-second then gladly said, let's do it! I removed the engine yesterday, carried it to KRE, installed it on the dyno and made it ready for the testing. It was dyno'd EXACTLY like it is tuned for the street and track. I used two different carbs during the testing, a 1976 q-jet and a Holley 4781-2 850cfm DP carb. I race the car with either carb and it runs identical numbers so figured it would make similiar numbers on the dyno.
Part of the testing would also involve carefully measuring my 6X heads for chamber size and actual port flow on KRE's flow bench.
Well, the testing was done today, in the interest of space I'll just go over the highlights. ALL runs were made with both sets of heads using my modified 1968 iron intake that accepts either spread bore or square flange carbs w/o an adapter. We tested both carbs with each set of heads. Timing adjustments were made to find the best peak power numbers. With the 6X heads my 455 made 455hp and 530ft lbs. With KRE's new heads it made 495hp and 564ft lbs. The qjet made the highest peak hp runs with either set of heads yet gave up a couple ft lbs at peak torque to the Holley carb. Average power with either carb was within .2 hp/.2 ft lbs. No wonder it runs the same numbers at the track with either carb!
The chambers on the 6X heads were right at 91cc and flowed 231cfm intake/196cfm exhaust. The KRE heads were 261cfm intake/221cfm exhaust with 85cc chambers. Cranking compression with the 6X heads was just under 160psi, right at 175psi with the KRE heads. With either set of heads the best hp/tq numbers were made with 30 degrees of total timing. 93 octane fuel was used for all the testing.
Next step, off to the track for some timeslips!......Cliff
__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran!
https://cliffshighperformance.com/
73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
|