I guess they are in since they give numbers at different lifts. I just wondered because when I had them ported I went for the 2" and 1.56 Manley, undercut race flow valves.

I thought that the race flows and bigger valves would provide even more flow.

They flow fairly decent for Lt1s, but I wonder how much, if any, I gained by the larger valves and the undercuts?

Thanks.

 

Did gain anything?

 

That's what I'm wondering. There is mucho discussion on heads and flow numbers, but not much discussion on going with bigger valves and undercut style.

I.e., was it a waste going with the bigger undercut valves?

 

Are you asking if the valves are actually used when flow testing? If so, then yes, you're flow testing a system essentially (port, valvejob, chamber)... so there's no sense in doing it without .

As far as the difference, it'll just depend on what was done to accomodate & take advantage of that particular valve's additional flow potential

 

righto, the port must be ported with the larger valves in mind, mainly the venturi and the port leading to the valve seat.

 

So (just curious) would the undercut type be the way to go when picking valves?

 

Well they're certainly not going to hurt . From what I've seen, the undercut stuff isn't going to make a huge flow difference or anything, but can pick up a few cfm. I honestly haven't taken the time to weigh the same brand/size/alloy valves with a straight stem vs. an undercut one, but a reduction in valve mass is going to be another benifit - even if it is a small one .

 

I see.. It sounds like one of the many little things that add up. Thanks!

 

Boy am I glad someone opened up this topic... I have some questions of my own.


How about those 3 angle cut valves or the polished ones?? I have seen those in other cars but am yet to hear someone using them on Camaros.. My understanding was that those are worth a couple of ponys... I also heard of indexing the spark plugs.. good for another horse or two. Long time ago I read a book that talked about all those seemingly insignificant mods that when added together made a huge diff on a race car.

you know like perfectly matching the weight of the pistons etc etc... no trying to hog the thread here... so lets go back to valves... what do you guys think of those 3 angle cut and polish valves?? they used to be a must on a race car...


Marvin

 

C'mon girls and guys... someone has got to know more about valves.......


Marvin

 

hEY MeNToCasE........wHAt PaRt Of THe IsLanDS yOu fROM?