| Senior Member
Join Date: Jul 2004 Location: Calgary, AB, Canada
Posts: 10,469
Car: 1982 Trans-Am Engine: 355 w/ ported 416s Transmission: T10, hurst shifter Axle/Gears: 10 bolt, true-trac, 3.73 | Re: can I run .470 lift safely with fresh 081 heads? Should be able to, but check to be sure.
Depends on the valve seals you've used eh? (and don't tell me what valve seals you used and expect me to know how close it is eh?)
Assemble the heads. Use a caliper to measure the height from top of retainer to the bottom of the spring (or any other good repeatable measuring surface). Then use a valve spring compressor of your choice, and compress the spring until something hits. Retainer to seal, retainer to guide, spring solid height, etc, and remeasure that height. That's your max lift. Subtract .050" for a safety margin, and that's your TRUE max lift that you should use. |