Thanks for the tune up info Bob C!

I have the plugs at .035"

It was at 161 degrees at the start of the pull at 4,900 rpm and climbed to 166 degrees (+5) at the end of the pull at 7,200. This gave a 12.5 A/F ratio on the gas scale.

The actual dyno elevation is only 918 feet and DA around 1200 - 1400 feet. I race around 3,000 - 4,000 feet DA so we wanted to not be fat on the dyno as it will be richer when I race.

I will tune for max mph and then check the temp gain in the quarter at my elevation and go from there, but at least it will be in the ball park.

We could have cranked up the vacuum and made a pull with the engine colder to try and break 900HP, but as everyone says "you don't race dynos"


Bob R, They say Alum blocks seal better after the first rebuild, but i am just going to go to a vacuum pump and not worry about it.

I did not use low tension oil rings, so when i rebuild i will try them for a few more HP

Cheers,

Arnie

Anyone know how much HP the low tension oil rings along with 10 - 12 inches from the Vacuum pump would add to the motor?

Also any recommendations on how much vacuum to set it for? I have heard you don't want to exceed 15 inches...

Cheers,

Arnie

On my motor, i saw 12 ft lbs torque difference for low tension rings Vs standard after assembly, so figure maybe 15 hp? The vacuum pump is supposed to be worth about 30 hp. So if you went from 859 to 890 hp, that would be about right, just for the pump.
As for vacuum, I will shoot for a safe 10 inchs, maybe 12 tops. Previously I have had 7 inchs at best. Already have signs of lack of pin oiling, will have to check with Manley and see what they say about pin bushings, oiling and clearances.