Always comp test at WOT , as you are trying to compress a negative pressure. Try Tighe Cams Brisbane for a billet 960C Racer Brown / high lift wks 76 or 525C wks 76 ground onto your cam with lash pads to suit And buy some brown undies as you will need them : )
Hey Aaron, you gotta have more faith in your measurements, and doubt any information you get from Crow Cams. You measured 229 degrees at .075" which is certainly way more duration than 212 degrees at .050" lift and much closer to what you originally thought you had. Obviously another mistake by Crow Cams claiming that any cam can have 290 degrees duration advertised with .470" lift and only 212 degrees at .050". Your measurements match what most people here in the US refer to as a stage 3 cam. Most of the flat top piston 280 block and head builds I have read about use a fairly aggressive cam like this to lower the dynamic compression ratio to run on pump gas with an N42 head. It should have plenty of duration and lift to make good power to 6500 rpm, so long as all your other systems can move the air. It seems like the perfect cam for your engine, since you don't want to rev it much higher than that. Just look at your dyno curve,, there is no lack of lift or duration causing the power to nose over earlier. So long as you limit yourself to 6500 or 7000 rpm, don't expect much more power with a more radical cam. You certainly could make less power at all normal driving engine speeds. When I have compression tested my engine, cylinder six is low by as much as 20%, and it seems to be blowing into the crancase (as opposed to out the valves) based on a leak-down test. It might just be ring seating, but my difference is great enough that I wonder whether I have a small head gasket leak say between the combustion chamber and an oil return passage. Not enough to fret over or keep me from driving it but something to look into next time I have the engine out.
Cheers Keith. Good to know regarding 'stage 3' cam. I now have a reference point for comparison of results. Whitleytune is working on a cam profile to match my motor which should see some good gains but that is a future project 😉
