I'm having a set of stock casting heads ported out for me but I can't get a straight anwser on the pros and cons of running a bigger valve. At first I was told that a 2.02 valve in a stock bore block can have shrouding problems. When I asked the person doing the port job for me, I was told that there shouldn't be a problem and that I should definately have the larger valves put it.

As far as the rest of my combination, I plan on a set of long tubes, the crane 227 cam on a 112lsa, ported intake, 52mm Tb, and I'm not sure what to do for rockers yet either. I left the less important things out.

So are 2.02/1.60 valves to big for a stock bottom end motor with stock bore? or should I have them put in?

 

That is a fine setup. just remember you will need to have new valve seats installed. You can TRY to cut them that thin but they will not seat properly and then crack.

I am running 2.05 int and 1.58 Ext

 

what kind of gain would u expect to see by going with a bigger valve, like the 2.02/1.60 setup, 2.05/1.60, instead of the traditional 2.00/1.56 valves?? same port job, just bigger valves??

 

The biggest valve you can put in the stock head without new valve seats is a 2.00" intake valve.

One of the head guys like Larry can answer the valve sizing question for you better and it has actually been discussed in some of the head threads on Adv Tech. Basically the bigger the valve the more potential the port has for airflow.

Bret