Torque plate with cylinder head valvejob

[Frankshaft]

^^^ I agree. I mentioned that earlier in the thread. Also you can try and cycle them in a head oven multiple times as new too, that seems to help

[gunt]

This is better put than I could , took me a bit to find it

http://dsportmag.com/the-tech/head-torq ... lications/

[Barry_R]

Maybe it doesnt work for all engines but when we ran NHRA stock eliminator with 428 Ford Cobrajets if you didnt do the valve job with a block plate bolted to the head the 2 end exhaust valves would leak. We found this by bolting the plates on a fresh valve job just to see what would happen. We then started doing the valve jobs with the block plates bolted on the heads and the car picked up a bunch. Bear in mind anything that picks up a stocker motor without spending money at all is huge, we arent talking 50 hp here but it does work

I can double up on this statement. Back a couple years ago (OK maybe a couple decades...) I had a well sorted 428 FE that I raced every weekend around Detroit. Car was not fast by modern standards but was deadly consistent - you could leave the numbers on the window for multiple weekends if you desired and drive to the number within a couple hundredths.

Holbrook had talked me into doing the valve job on torque plates at extra cost. I hurt the engine after a while (rocker shaft & lifter) and figured I could tune up the valve job while it was apart - I had a concentricity gauge and all the stuff since I was now doing heads at another shop in the area. Made it as perfect as I could, reassembled it and noticed that you could hear air whistle out of the end exhaust ports when pressurized. Car was about a tenth and a half/two tenths slower if I recall correctly. Pulled the heads, took them to Carl, told him what I had done. They touched them up on the plate, reinstalled and the times came right back.

Never saw or heard that leakage on aluminum heads. Figured the pressed in seat ring was rigid enough to resist the bending load.

[mag2555]

Just 2 weekends ago I touched up two Leaky intake seats on a buddy's stroker 454 with China made Aluminum heads.
All of 5 seconds of spinning the stone up got them back into shape and I drove in the car with him before and after the fix, the cylinder pressure went from 135 to 160 and it ran like a different motor so I can just imagine the loss of performance from having 4 or more valves not sealing well!

Oh any by the way both seats where off in the same spot , that being the shallow side of the chamber so what does that tell you about China made heads!