bigdsz

iTrader: (1)

I'm putting together my 408 from Erik and I just got the heads on and started on the rocker arms only to find out that I had only .025 clearance from the bottom of one rocker arm to the edge of the retainer. The shop that freshened my 5.3L heads ground down the tips of a couple of the stems to make them even and I think that's whats causing the problem. Am I good to go with only .025 on one of the exhaust valves? The other seem to have like .050-.060 clearance.

JPH

iTrader: (2)

check your geometry.

bigdsz

iTrader: (1)

It's not a matter of geometry at this point. The engine is on a stand and the lifters aren't pumped up yet. My concern is if .025 rocker to retainer clearance is too little.

Grimes

iTrader: (3)

http://www.chevyhiperformance.com/te...springs_guide/

according to this article, .040 is acceptable.....maybe you can get a lash cap like they suggest for that one valve to regain that height?

vettenuts

iTrader: (4)

If the geometry is correct the lash cap will throw it off. Whatever you do, don't grind the rocker like I saw in the LS1 performance book. Can your wipe pattern tolerate any shimming? Other option would be another rocker design with more clearance.

bigdsz

iTrader: (1)

Thanks, that was a great article. I do think my geometry is screwed up with a big bias to the intake. That would mean I need to shim, if I'm thinking right and that would most likely solve my problem. The motor is still on the stand and the new Caddy lifters aren't pumped up so that I can get an accurate wipe. I think I am going to pull the heads off and replace the valves. Absolute Speed used .080-.100 longer Rev valves. That, and the shop that just did a valve job on these heads, surfaced the valve stems so they would all be the same height, are the cause of my clearance problem. Wish I had the $ for new heads that the short block needs, because what ever I do with these is a compromise.

Grimes

iTrader: (3)

cool, well good luck whichever route you decide to take...tell us how it turns out!