Not many mercury engines were making 1.7-2.0 hp per cubic inch, turning 6000rpm or more rpm, with 500lbs of over the nose spring psi. The closest thing to what we run dan, was the 900sc/1000sc. It indeed had stud girdles, with its roller cam, and spun a max of 6000rpm, brodix heads, 10-71 blower, etc.

Most of the others were 5200 max rpm, with fairly light spring pressure, and not making a whole lot of cylinder psi. Opening an exhaust valve against 800lbs of cyl pressure wont be as bad as say 1300psi on a boosted or high power deal.as for the .hp500 500efi, 525, 600sc ,800sc, etc. Those were all mild 5200rpm engines with light springs

The 1075+ up engines use shaft rockers. :cool-smiley-011: :bigbird:

They transfer vibration and harmonics equally to the entire valve train.:D

The 850sci also uses the same shaft rocker set up

What vale covers are you using with those??

With the girdle installed they're all tied together but otherwise the outboard end, where the polylock goes, is free to deflect as it sees fit.

There are a cast aluminum, very nice for the price, I got them off ebay.

these are them but they machined breather in them, notice no lettering. I paid about 160 bucks a pair for mine

http://www.ebay.com/itm/NEW-TEAGUE-C...pWazkw&vxp=mtr

I'm not sure if it's me or the beer, but that pic is fuzzy!

Check your PM's!

its fuzzy, I got ur pm............why u drinkin so early

Just a good day to drink and make chili!

i think you mean the top of the stud.the flexing will actualy happen from the bottom of the poly lock to just above the mounting hex.the higher the lift&spring pressure the more stud deflection.