Four, if the cam is steel, you are supposed to use chilled iron lifters, if the cam is cast iron then you can run the typical replacement lifters.At any rate you should run new lifters on the cam.I heard the wrong lifters can chew up a cam quickly.If you have any doubts, contact the cam maker for info, I think Crane bought out Wolverine, check their website. the Howard M4F has about .421 lift at valve and 206 degrees duration at .050 lift. M4F advertised duration is 236 degrees. The advertised lift includes lifter take up clearance ramps and is not a good judge of cam performance.The following is the specs for a stock 261 cam, advertised duration,290 degrees, duration at .050 lift,190,valve lift at intake,.416,valve lift at exhaust,.408 Your cam sounds milder than the stock one, but lobe centers and valve opening rates are probably different.
