Yea 8" is enough. The pushrods shouldn't be over 7.450" so 8 is fine.

 

The cam lift is a bit higher than that, so I’ve opted to use a roller tip rocker and the cam is specced for a 1.8. I plan to use the comp cams ultra pro mags. Does this make a difference?

 

wipe pattern can not be checked accurately with a non pumped up hydraulic lifter. this would be were taking apart 2 lifters, one for intake and 1 for exhaust to make a solid lifter as previously mentioned would be helpful. yes you can change swipe pattern with stock rockers by shimming, but honestly if you care enough about swipe then you should be buying aftermarket rockers.

 

I would put it together permanently and check the wipe pattern with a PUMPED UP LIFTER and CHECKING SPRING. Thats just me. Along comes 20 other ways so take your pick.

 

Can also reference the manufacturer's instructions.

https://www.compcams.com/pub/media/p.../5/151_52_.pdf

Assuming the use of 1677 rockers since they are BOLT DOWN 1.8 LS1 Ultra Pro Magnums. And you said you're not using adjustable rockers.

 

Since the rocker arm is on a fixed pedestal the swipe pattern will be what its going to be unless you find some way to shim or use lash caps and you will still be able to check swipe on the new hydraulic lifter once proper PR length is determined and installed. Turning the motor over by hand is still going to roll the rockers over the valves.

 

I think you guys have me on the right track now. Thanks for your help!

 

What did you get for a pushrod length using those 2116LSR lifters?

I'm hitting zero lash at 7.465" not sure what's wrong here. My build is a LQ9 w/ vinci cam, stock rockers, head gasket at 0.053", rebuild 317 heads to factory dimensions (as seen at valve stem).... Roger who cut my cam said he's never seen a length over 7.450" for a build like mine... He'd never used the 2116LSR lifters though.

My measurements are here: https://tinyurl.com/3x2x7mkj

 

I'm seeing consistency there and if your confident in your measurements then go with it. I've read that Johnson lifters require longer than stock but I'm not sure what the difference is and they may be able to tell you.