big valves on 352

[NewFalconOwner]

I got my C6AE-U heads back today, shimmed up the rockers and had fun.



I bolted 1 head on the motor tonite, 2 solid lifters and pushrods and used No.8 since it was easy to acces it for me, and spun the motor over a few zillion times waiting to hear, see, feel, evidence on hitting, but never did. took the head back off, and looked for marks, or pattern but couldn't see anything. Stock bore 352, .020 down the hole flat top no reliefs, 2.09/1.66 valves and crane 99893 springs (Alex parts). Inner spring is removed, but still should be some contact or should I just clean and assemble and let her rip?

[chris401]

I am glad you did that. I have a pair of C8AE-H heads with CJ valves I have been wanting to put on the same block as yours. Now I can bolt them up and look through the bottom with a good chance of all clearing.
Thanks

[NewFalconOwner]

oh, please don't take my word for it, I maybe screwed up my measurements lol

[My427stang]

It'd be pretty hard to hit, even with a smaller bore, here is a 2.15 / 1.67 combo, C8AE-H heads in a 4.05 bore.  You can see the exhaust is a bit closer, but there is plenty of room.  The intake side has toom to spare. 

[NewFalconOwner]

I will clay it tomorrow and see for sure.. thanx

[NewFalconOwner]

I took a short video with my scope camera, heres the results

http://www.youtube.com/watch?v=2NlOIGgVSMI

[Joe-jdc]

That picture is deceiving.  The valve does not come straight down in relation to the bore, but at an angle, making it closer to the wall than the picture would indicate.  It may still work at your valve lift, but best to check at valve lift plus a cushion/safety margin of a few thousandths.  Joe-JDC.

[NewFalconOwner]

picture? my valve lift will be around 610 or so

[My427stang]

Joe is 100% right, but in my pictures, the 2.15 valve never hit the wall, and the 1.67 exhaust didnt hit until the keeper grooves were below the guides.

Need to check though, and equally important is radial clearance to the piston top.  FEs don't seem to be too fussy, but 385 series builder pistons barely have enough room for stock size, so it's always good to check

[NewFalconOwner]

how can I check that with the cam that's in there already.. its the stock cam, sure the lift isn't as much as what I want to put in.

[Joe-jdc]

Clean the top of a piston, and put a dollop of model clay on the top of each valve relief.  Lightly coat the face of the valves on that chamber with WD-40, install a used head gasket, install head with about 4 bolts and snug in place.  Install those two pushrods, rocker arms, solid lifter, etc,. and rotate the piston through at least two complete cycles.  Remove the head and measure the thickness of the valve indention in the clay by cutting the clay with a sharp knife, and measure the thickness of the undisturbed part of the clay.  Now multiply the difference in cam lift by 1.76", and see if you still have sufficient clearance in the depth of the clay.  You should have at least .100" intake, .070" on exhaust valves.  If not, then the pistons will have to be notched to give you the desired clearance, or less camshaft will be required to be safe.  Joe-JDC.

[NewFalconOwner]

thanx a lot for that joe