Changing valves

mustang70

Founding Member
Nov 15, 2001
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San Diego
I'm thinking about putting a set of high flow valves in my stock heads. The heads have been ported, but they still have the stock style valves in them. I was wondering how much of a difference in flow there would be if I went with the style that necks down by the valve head. Still going with the stock size. Would it be worth the expense?

Now for everyone that's going to tell me to get a set of aftermarket heads...I'm not interested in that at this point. Budget is a partial reason, but I have some ideas brewing. TIA.
 
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The valves that are necked down on the stem will increase the flow #'s a small amount in stock valve size. Not enough to really tell by the seat of the pants. If your going to buy new valves. Your better off getting 1.94 Intake-1.60 Exhaust valves with the necked down stems. There about the same price as the stock size valves. As far as the machine work is concerned in opening up the seats and Bowles it really doesn't cost much more either. Todays seat&guide machines Like the Serdi or Newen Don't really care what size the valves are. They can open up the seats and bowles in a matter of minutes With muti angle seats. Doing this to the heads there will be a dramatic increase in flow #'s.
 
The under cut valve will increase the low lift flow numbers ( there are a lot of articles out there on just the valve change). they say after about .400 lift the under cut isnt helping any! IF you go larger valve size , go to the GT40 size ( 1.85/1.55) the notches in the pistons from Ford are cut for that size... the 1.95/2.02s might cause interface issues and the increase in flow from the 1.85 and 1.94 is really almost nil, with out bowl and good port work, not to mention shrouding issues...cool??

SOOOooo... under cut valves HELP!! 1.94s really dont for all the clearance issues that might arise!! 1.85s are good choice!!

Just me............................



Thumper
 
My valves are already 1.84 and 1.55. I pulled out a caliper and checked them myself. I have dished pistons, but I'm planning on changing that this time around. On the intake side I mostly cleaned up the bowl area. I spent more time on the exhaust. Thanks for all the help guys.