james.frazita

Is it possible to down size 2.25 intake valves back to 2.15? They are on a set of 3919840 BB heads, 427, 435 HP. The heads are basiclly stock and have never had hardened valves installed. THOUGHTS!!!

gkull

I have had a head shop remove my valve seats and remachine the ports and seats for bigger valves. So I would say that you could install larger seats for a smaller diameter valve. The only problem with that is the intake port wall contours are going to be all wrong with an even smaller intake valve and partially unsupported valve seat. The valve is always the bottle neck in the port.

What is the reason that you are attempting this?

james.frazita

Not sure if I need to install original valve size. I use TRW 2300 pistons with cutouts for valve clearance. I will clay them in this winter to see how much valve to piston clearance I actually have. I there a way to open/cut piston clearance without removing the pistons IF I need to???

gkull

Only radical cams require valve clearancing.

It is much easier to remove 8 pistons and have them machined than installing smaller valves

427Hotrod

The depth isn't usually the issue with the big valves...its' the radial clearance. It gets real cozy around the edges with cams in the .600 lift range usually. I just use that as a reference..it's not the lift that is the issue, it's how aggressive it is, how advaced it is, what LSA is etc. Generally cams around .600 lift are getting pretty fast opening.

Isky makes a tool you can use to open notches with engine assembled. If you pull pistons it's pretty easy for machine shop to open them up.


JIM