I currently have 14 degree heads on my 622 BBC. I am thinking of putting a set of 9 degree heads on it. My question is will the pistons work along with the valve train. I know the pushrods will probably need to change.

If your pistons are "flat top" then I would think they would probably work. We are running into a situation where we bought a 565 tall deck motor with 14 degree heads and 18 degree pistons that have a 13cc dome. This caused the use of a very thick head gasket and depending on how the cam was degreed, it shows 3 degrees retarded on the jesel belt piece. For your situation, you may just need to check piston to valve and if it hits the piston you can always fly cut the pocket.

The other issue I see here is that is that you really want the valve reliefs cut on the same angles as the valve.

Professional Engine builders with more experience might be able to chime in on this and maybe they will disagree.

My understanding has always been by having the valve relief at the correct angle in the event that you do break a spring and the valve touches you may get away with it without bending a valve. If the angle is different you are likely going to bend a valve. This is going back to helping on a comp eliminator car where they were running very tight piston to valve and a ton of rpm. Maybe a combination with lots of piston to valve would be more forgiving on this.

Piston Valve pocket angle should always be the same as cylinder head valve angle and rotation. This is where clay can show what is exactly going on, where just an indicator will show the closest part of the valve touching the relief.
Depending on top ring location , diameter and radial thickness there may or may not be enough depth available in the intake relief to do this.
Sometimes new pistons are in order.

This is a great article from Reher Morrison on checking piston to valve clearance. I have used these techniques since I read this article years ago and had good success. It takes a little more time but its very accurate.

http://rehermorrison.com/tech-...rance-the-right-way/

You will need to have the valve relief for the new heads cut on the pistons if you were close with the 14* heads.

Also the chamber on a 14* head is usually much bigger (In the 80-90cc range) compared to most probably in the low 60cc for the 9* heads. So this will dramatically increase your compression ratio which may force you to change pistons anyway.

You will also need valvetrain specific to that 9* head.

Pascal,

Thanks for the info. That is what I needed to know.