75 440 Sno Twister F/A grass set-up

[cbxman]

I am putting together a stock 75 S/T 440 f/a for grass dragging. The cylinders are out for replating and boring to 68mm. The crank will also be gone through so I will be starting with a fresh motor and new Comet 102C. What speed can I expect to get at 500 feet? Is 70 mph possible? I need to be at 7.45 seconds ET and approximately 65 mph to compete with the local competition. Thanks.

[nitrofa340]

My '75 Rupp F/A 340 stocker has run a best ET of 7.26 @ 64 mph at the Princeton grass drags here in Minnesota. My 440 Rupp F/A stocker has run a best of ET 7.11 @ 69mph. So yes,.....the ET and top speed you are looking for from your Merc are achievable.

[cbxman]

Thanks for the info. Those numbers look good. Just curios - what do you use for clutches?

[nitrofa340]

Thanks for the info. Those numbers look good. Just curios - what do you use for clutches?

I like the hex. Other guys have better luck with the Comet. I know Tom Priebe over in Wisconsin runs a Comet on the '75 Merc 440 that they run, and that sled is fast,...... probably faster then my Rupp. Alot depends on which clutch you are more famaliar with and have the most parts/experience to tune.

[cbxman]

Finally finished the sled. I decided to go with Polaris clutching and have had good results. My first pass was a 7.44 @ 500 ft. After a few adjustments and five more passes, 7.36, 7.29, 7.24,7.20, my last time was a 7.16 with a 1.87 60 ft time. My best 60 ft so far has been 1.81 sec. Still spinning about 10 ft off the line (no clay) - thats with 132 chisels.

Would love to break 7.00 flat. Back to the test track.

[nitrofa340]

Sounds good. Not too many free-airs of any brand will run with a dialed in Kohler in Stock class drag racing.