val and val. job??? for the head guys

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earthmover

earthmover

in the tire smoke
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buddy has a dart with a 360 with j heads 915 and flow 250/180@550 with a old val. job 3angle and stock val...now we was talking and asked if i thought if he went to nail head style val. and a 5/7 angle val. job(race) would he pick up cfm and power......i think so because the val. has a better design and the val. job will let it flow more....it should make a little more comp. not enough to worrie about from the dip in the stock val. to the flat val. but the val. job alone should make some diff.....whats your thoughts on this....and how much should it pick up with the val. and the val. job...or why you think it want help...
 
bOb shingler said:
mopar doesn't recomend nail head valves. they are heavier. not sure what a 5/7 angle is. maybe 50/70 degrees? i'll assume that's the throat angles.
Click to expand...

Where is this info? I'll have to look up mine, but I always heard that intakes flow better with a nailhead and exhausts flow better with a tulip! But most readily available stainless valves have more of a nailhead design on both, including the ones Mopar Performance sold.
 
hay bob the 5/7 angle is the val. job either 5 or 7 just like the 3 angle as what the mach. shop tells me and they said its better due to the angles for more flow but i have no idea...also ive always heard that the new nail heads where better by design and stem that has better flow pot. but i just know what i have been told over the years....had a set of econo w2 that i got new no val. or anything and was told to use them for more perf.
 
hmmmmm, i'm just trying ti recall some old infomation from my tin bucket. for all i know i may have got it backwards. i thinking it was in an old dc engine manual but maybe the techno stuff has changed since then.
 
earth, if it's a 50* seat and a 70* throat angle the valve will have to lift further off the seat to get good flow. low lift will be bad and high lift will be good. but then again maybe 5* ain't no big thing.
 
A lot depends on the previous work. If this 3 angle was done with stones and tapered pilots and the valves truly are stock, I can see at least another 10-15cfm easy through most of the lift range just in replacing the valves with nailhead performance valves. The gains being more from the back cut and narrower stem than anything else. The heads have been ported, so gains from the throat or chamber cuts may be negligable if that was already done. In terms of cutting accuracy and concentricity, and installing oversized valves so the seats can be placed out towards the chamber more, those will add power even if they don't show much on the flow testing. I think what he might see, again dependant on what was already done, is a larger gain in the lower lifts with a slight gain at lifts over .450. I'd say have a modern piece of equipment do the work, install 2.05/1.65 valves in it moving the seats out properly, and stick performance valves into it. A small amount of hand blending might be neded in the throat depending...
 
better multi angle valve job is gonna pick it up for sure.
Skinny stems and less valve in the way will also pick it up.

If you flow them after, I think you'll see a gain of 10-20cfm up till .450-.500 lift.
depending on the bowl/short turn shape/pinch cs, maybe hit 260cfm.jmo

but really, with a macinni ss semi tulip 2.02 intake and just a lil short turn and pinch work and minor roof kink blending I had [email protected] on the intake.not much work there.
 
he says the val. are the ones that came in the heads and hes looking at the milidon,or the farr(i think) thats nail head....i have milidon in my heads look like a good val. not very high dollar wise.....what amount of power could this result in would it be noticed .....what would you guys rec. as far as val. and the 5 or 7 ....
 
more angles the better, however it depends if they have to sink the VJ in order to get them, like the top cut that make a nice smooth bowl'ish transition to the seat from the chamber.
They say ferrea valves are the ones, check out the 5000 or 6000 series on e bay.
 
I typically run the cheaper SS imported valves. They run about $200/set and are comparable (if nto the same) as Mancini's, but no tulip. I dont build competition engines and that is where I'd use Fererras or Milodons. As far as power, that all depends. The ports are only a part of the entire package, and chaning them may require a new cam and torqie convertor choice to really work well. It all depends.
 
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