One of the guys on the Fordbarn sent me a cam to check out for him. It's on a 59A core and is stamped Grancor 59 and was tagged as "Indy grind" . Here are the cam events measured at .050 vlave lift: EO - 50 bbdc; EC - 9 btdc IO - 6 btdc; IC - 44 abdc Gross Lift .260 exhaust; .258 intake Lobe c-line 119 exhaust; 109 intake The cam has a pretty broad nose with lift of .250-.260 for about 60 deg rotation. Notice the lack of any overlap at .050. Would this be a blower grind? All comments welcome. I have no experience with any Ardun cam specs.
With that -2 overlap it looks like a blower grind. If I've done my math right, your cam would be 230/222 @ .050", LSA 112+5. Probably not really one that'd go in an Ardun, though. I'm pretty sure my father's Ardun has an Isky Max-1, but his build records are bit sketchy. Two of the McNicholl's flathead build books use these two grinds in the two Ardun builds detailed in the books. Unfortunately, the specs are kind of lacking. Blown: 222/222 @ .050", LSA 112 N/A Street: 227/227 @ .050", LSA 110
Thanks for that info. Seems strange that they would cut the lift off at .260 and have such a flat nose.
Just did some reading and may have discovered the answer. Was reading up to find the rocker ratio - which was 1.25. An article by Ray Brock said that the early Ardun valve springs were so tightly wound that they were only good for .280 lift at the cam which netted .350 at the valve. So anything over .280 resulted in coil bind and bent pushrods. So this must have been any early Ardun grind.