505 dyno test results

IF…….. it’s indeed a lifter issue…….a set of solid rollers lashed tight “should” show improvements up top.

The curve looks pretty normal to me thru 5600.

A little dyno story……..

There was a dirt circle track motor on the dyno one day.
Built by a guy that worked for a shop we did dyno work for.
I wasn’t the one running this particular engine……and when I got to the shop they had already been making pulls.
They were doing some trouble shooting, thinking there was some sort of upper rpm ignition issue.
They couldn’t find one, so they went to make another pull, but the dyno wouldn’t load the engine…..at all.

So, they fill me in on what was going on and I try to make a pull……no go.

I see the upper limit was set at like 7200.
I look at the display of the last pull.
Last line is like 64-6500.
I was like, “oh………the last pull isn’t over yet. The computer is waiting for the engine to get to 7200 to end the program”.
Hit the “stop program” button…….motor loads up fine.
Make another pull……..motor just flat lines at 6500.
Hard into valve float(this was the “ignition problem”).

Builder couldn’t believe it…….since he got the recommended springs from the cam supplier.
He told me the pressures……nowhere near enough imo.
Done for the day.
Brought it back a few weeks later with different springs…….which were barely enough to get past 7k.