Do you have any buddys that could help you?? I have done that for some of my friends and two heads are better than one often, especially when you get tired.
If you are not changing the cam, finding 0 lash should be much easier if you are sticking with the stock non adjustable rockers. You Ford guys have it easy that way, I've spent hours with my adjustable rockers on my chevy engines.
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Frank W
90 5.0 LX coupe Stone stock soon to be daily driver
74 Chevy Laguna Type S-3 305 apart in garage, getting a 454 to put next to it
www.chevellepages.com/folingo