340 X Head Valve Options

SheSaid said
Well, I mocked up the valves in the head next to the old valves and measured my current spring install height. With the valves sitting in the old valve seats I have 1.62" spring install height on the intake and 1.58" spring install height on the exhaust. I am aiming for 1.80" install height. So as of now I am going to see if I can set the valves .050" deeper than the way they sit now, take another .050" off the spring cup (unless I will hit water) and also remove the Hemi spring damper that has an additional .050 clip on the bottom of the spring. That would net me an install height of 1.77" on the intake and 1.73" on the exhaust. Seems very possible. I will know more once the guides are set and valve job is complete. Then we can actually measure the real spring install height. I need to physically measure these springs to figure out their open and closed pressures.

I found 5.7 Hemi valve guides for the 5/16 valve stems on RockAuto for less than $2.00 each. I also ordered hardened exhaust seats. This way I will have all the parts needed to do the valve job and will eliminate any head scratching at the machine shop.

I am considering doing the valve job and porting work backwards. Getting the guides and valve work completed first and then start porting, using clay or something to cover the valve seats. Not sure if anybody else has tried doing it that way.

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Ok, we need to slow way down and figure out what you are doing, and why. First, why do you think you need a 1.800 installed height? I run 1.72 or so and I NET .600 lift and that still gave me .090 to coil bind so I can shim .030 if I ever need to. You keep moving the tip of the valve up (towards the valve cover) by sinking the valve, or making the valve longer, just makes it harder to correct the rocker arm geometry. This is covered on the B3 racing site. At .620-650 lift you are pushing the stock valve gear to its limits.

Second, you always always always do the guides and seats BEFORE you port. Only run hard seats under the exhaust valve, not under the intake valve. It's a waste of money. The valve job establishes the percentage of bowl to valve among other things. If you aren't careful then cut the seats .030 smaller than finished diameter and then do the porting. You still have to finish the valve job and the port work without singing a seat.

Seems to me you are stuck on the 1.800 number and there is no need to get there. Do a good valve job, get the top cut .060-.100 wide and that should put you at 1.72 or so and that's good enough for .625 lift.

Didn't see the caliper pics. You already have all the installed height you need.