Q on valve stem height

[3406pk]

I have a 72 340 engine out of my Challenger that I'm rebuilding. Bored .030, stock crank, forged pistons for 9.4 CR. It will have mild cam just a bit more than stock for a resto cruiser. Anyway I got the J-heads back from valve job (new guides, seats, all new exhaust valves) and was checking out machine work. Valve spring height is all within specs but valve stem height varies about .020. Was going to check the service manual to see if within tolerance. That's when question came. See the picture from 1970 Service Manual. That shows Tool C-3968 for checking. I don't have one, but I measured the tool at Chrysler dealer shop. That tool measured 1.980 to 2.058. I checked to tallest valve stem and that was 1.920. So I talked to machine shop machinist and his "Bible" shows spec as 1.907 to 1.937. So all of my valve stems would fall into the last set of specs. And he only replaced exhaust valves. Did the spec from Chrysler change between 70 and 72 or "Whats the Deal." I'm going w adjustable rockers so the variation won't be a big deal. Appreciate any help and info. I searched several threads for valve stem discussion, but couldn't find length given. The engine ran good no valve clatter or problem before teardown, just low on compression.

 

[oldkimmer]

......I always make sure the heights are the same , if there .005 difference they get a pass on a daily driver but for anything else there all even or there made even........kim.....

 

[Locomotion]

The valve stem height can also be affected by the valve job. If some seats are ground a bit more (sunk), variation in seat installed depth and/or amount ground off of the valve head for the valve job can alter the height on the other end. Best way to check the actual valve lengths is to take them out and compare/measure the intakes and exhausts against each other.