Tin Indian

I plan on having a set of 5.7L Stage 2 heads with 1.57"/2.02" Ferrea valves milled .035"

This will be with the stock GM head gaskets.

Do you see any problems with this head combo when used with a TR-220 cam?

I understand the CR should be about 10.6 to 1
Does this sound about right?

Thanks,
Ron

LS1derfull

Yes on both questions, i used stock length pushrods before and after switching to heads shaved .035" with no valvetrain issues. This was with comp grind similar to TR 220.

Tin Indian

Your up early on a Sat morning!
Not me, it's 9:45 Saturday night over here.

Anyway, somebody measured the base circle on his TR cam a while back and came up with a 1.492” across the lobe distance. That would work out to be 0.746” centerline to heel distance. Thats .030” less than stock.

Jason at Thunder is going to measure a TR-220 with a micrometer and get back with me. I would bet that the centerline to lobe heal distance is just about .030" less than stock too.

Milling the heads .030"- .035" would then bring the lifter preload right back to about stock.

In fact, I already purchased a set of Thunder 7.40" stock length rods.

You don't think milling .035" off the heads is any too excessive do you?

Ron,

LS1derfull

I have run both preload settings and had no issues with noise, valve float or lifter pump up.
My preload was .039" less than stock cam with 7.400" pushrods just as a point of reference. I have no knock issues with 10.6 to1 compression on 93 octane, even with Hpp3 power tune no problems. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

LS1derfull

I have run both preload settings and had no issues with noise, valve float or lifter pump up.
My preload was .039" less than stock cam with 7.400" pushrods just as a point of reference. I have no knock issues with 10.6 to1 compression on 93 octane, even with Hpp3 power tune no problems. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Tin Indian

Thanks .....

Again, will .035" bring the CR to about 10.6 to 1 on 5.7L heads?

Ron,

LS1derfull

Ron i allready answered yes to the compression question up above.You will have between 10.6 to 1 and 10.7 to 1 with .035" off head surface. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />