GrannySShifting

iTrader: (10)

Im looking for 2.000 and 1.55 or so valves, undercut in the exposed part of the valvestem like the race or street flos manley offers

xssive

iTrader: (123)

Do you not want to use the Manley's?

LS1derfull

Ferrea and Rev have undercut valves also, Rev is more of a undercut than Ferrea. There are way more important aspects of these valves that make one flow better than the others.... <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Ragtop 99

iTrader: (7)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong> Ferrea and Rev have undercut valves also, Rev is more of a undercut than Ferrea. There are way more important aspects of these valves that make one flow better than the others.... <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No point in stopping mid thought...share your views on the flow characteristics of the Manley, Ferrea and Rev valves.

LS1derfull

I have worked for months coming up with my own conclusions on best flow with different valves. The stock valves are consistantly the best flow with all the different styles of heads and porting that i have done. This is the first type engine i have seen that this was the case. My best advice is to stay with stock 2000 and up intake and exhaust valves unless durability is a concern from boosted application or real high rpm.
I would love to see aftermarket come out with stock replacement in severe duty steel alloys. Upping valve size in 346" application is not worth it from what i have found. This contradicts what most on here recc: and believe but i dont follow the herd, just in pursuit of most power with least diffuculty, such as PTV problems, etc.

LS1derfull

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Ragtop 99:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong> Ferrea and Rev have undercut valves also, Rev is more of a undercut than Ferrea. There are way more important aspects of these valves that make one flow better than the others.... <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No point in stopping mid thought...share your views on the flow characteristics of the Manley, Ferrea and Rev valves. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ragtop, to directly answer your question, Ferrea flowed better than rev on my lates 5.7 stage2 intake port(2.02") i havent tested Manleys yet. I will post comparison of each on same head when i get a chance to test them all. All the aftermarket Exh. valves i have tested flow close to stock valves, also because they have all been tulip shaped same as stock.

white2001s10

iTrader: (4)

Well unless you open the seat up to a high percentage of the bigger valve diameter then it makes sense they wouldn't help flow.
Don't you think that wide margin intake valves flow better than the very thin stock valves?

I'm looking for some very wide margin valves that are also undercut and fairly light.
I think the wide margins would increase high lift flow #'s as someone else stated in another post.
What do you think about that?

LS1derfull

Yes i did open up throat dimensions to the same percentage as i use with stock diameter valves. It still did not benefit, i have a set of Ferrea 2.02" being reworked now to thinner margin and back cut treatment to benefit from flow gained from this. Thicker margin is not beneficial in my scenario, it reduces PTV also, and is adding unnecessary weight.LS1 port does not behave like old school Chevy heads, and modding it is very different imo also.

Jantzer98SS

iTrader: (54)

Yeah what he said. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

I'm amazing how much the different valves change flow on these heads. I have tested Ferrea, Manley, REV, 98, 00+ valves and they all act different. Then you have backcut angles and depth. It's a tricky game of cat and mouse to find the best combination. I think the 98 valves suck and I still have the stockers in my car, but not for long.

And as if that's not enough, hit the short side with a grinder and play around. You'll make or break it RIGHT there. I'm amazed with what you can do in that area as far as shape goes. You can port and port on the port with little changes in flow, and you can port little in critical areas and watch numbers go up like crazy. Amen for the flow bench, because without it I'de be lost.