dalematney

Shhhh > anciet chinese secret.
:lol: :lol: :lol: That was to funny.

suicidebomb

It's too bad Smokey Yunick is gone. He could'a got 700 horse out of this motor.

dalematney

I was told to have the valves grinded to allow better air flow. Is this true?

oldandtired

Most aftermarket valves will have swirl finish, undercut stems. For a little more, backcut the head of the valves.
I am unsure what valve jobs are legal, but a five angle, three angle or radius job are all options to consider.


Dave

dalematney

I hate to sound silly, but what and how is a back cut done. Does it allow more air flow. I know that the rules doesnt say anything about valves so i assume that it legal. Thanks

desoto30

a backcut is a different angle (in your case 30*) cut from the normal seat angle ( IYC prob 45*) It goes from very near the edge of the seat inwards till it goes into nothing into the head of the valve( hope this is clear) It is done on a valve refacer. It will allow more airflow as will paying very careful attention to the valveseat area specifically as Dave has stated.I would also add since valves are "free" in these specifications you may consider thin stem valves also.

dalematney

Thank you. Looks like the information that I need is getting good.

oldandtired

I also do a 25 degree top cut on the head of the valves. But do not compromise the thickness of the valve (leave margin at .030 to .060).
A top cut will create a tighter cone shaped air flow areound the circumference of the valve head, especially important on the exhaust valve.

Dave