LS7X World Products Heads Question
Looking forward to hearing more about your heads. Thanks guys.
Looking forward to hearing more about your heads. Thanks guys.

Isn't the GM LS7 valve stem metric? If so, they won't work in the LS7X head.
Once we determined to change directions and not use the gm valves, I basically put them out of my mind. As far as being a direct swap I would say no. The 8mm valve stem is .31496", we are using 5/16" valves which are .3125". It doesn't seem like very much of a difference... until you try to run it. We have customers who currently spin their sbc motors up to 7500 rpm. We don't think that the valves we use are limiting or handicapping.
B

I talked with a gentleman from Manley earlier today while inquiring about Ti valves (I also assumed the GM valves wound not fit). He suggested that I'd probably be fine with the SS valves spun to 7k (as you've stated).
Another thing he mentioned which I found interesting, was that he strongly suggested I use the Super Duty Series valves rather than the Race Series as he didn't feel the Race Series are rated for the high temps which are created when used with FI. He said the Race Series were only rated to 1225*F were the Super Duty series were rated to 1375*F. He said the Race Series valves would be over taxed if used with FI, which I'm using as you know. Since the price between the two is minimal, can I assume WP will be spec'ing the SD valves? If not, will this be a low cost option through you guys?
As always, thanks for your time B!!!

Also, check your PM's.
Typical uses of a 2.20" valve are big block engines, Clevelands, and SB2s. There valves are typically either made of titanium or have 11/32" or even 3/8" stems. A 5/16" stem on that large a valve could have maintenance issues. I think they are commonly used like 7mm on small blocks, where replace during maintenance would preceded valve failure.
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Thanks,
David

I talked with a gentleman from Manley earlier today while inquiring about Ti valves (I also assumed the GM valves wound not fit). He suggested that I'd probably be fine with the SS valves spun to 7k (as you've stated).
Another thing he mentioned which I found interesting, was that he strongly suggested I use the Super Duty Series valves rather than the Race Series as he didn't feel the Race Series are rated for the high temps which are created when used with FI. He said the Race Series were only rated to 1225*F were the Super Duty series were rated to 1375*F. He said the Race Series valves would be over taxed if used with FI, which I'm using as you know. Since the price between the two is minimal, can I assume WP will be spec'ing the SD valves? If not, will this be a low cost option through you guys?
As always, thanks for your time B!!!

Also, check your PM's.
Did Manley give you any prices on a 2.200 titanium valve?
Have they been flow checked yet?
Prices yet?
.
Thanks,
David
David, they are a cast version of a cnc'd port from a valued source.
Dune, in our cylinder head we believe we have left enough material to install a Jesel system.
David, according to our sources (valve and guide suppliers) the 5/16 stem should not be a problem given adequate bearing surface (7 times diameter). We have that. Our big big block uses 11/32 stems with a valve size of 2.300". Even in our 900 hp drag motors we use 11/32 stems. So we are reducing the diameter of the valve by .100" and only reducing the size of the stem by .015" per side. In my opinion not significant and will provide adequate durability.
Guys, in all out everything goes, class driven, weight restricted, SANCTIONED racing applications, grams I'm sure are worth fighting for. And yes weight = parasitic drag. I think the issue is really not worth the time being spent on it... Why then did GM do it? To wring every inch pound of torque and power out of the motor so they could stake the claim as having the first production car motor with 500+ horse power (505 I believe was reported).
I hope this helps.
B
David, they are a cast version of a cnc'd port from a valued source.
Dune, in our cylinder head we believe we have left enough material to install a Jesel system.
David, according to our sources (valve and guide suppliers) the 5/16 stem should not be a problem given adequate bearing surface (7 times diameter). We have that. Our big big block uses 11/32 stems with a valve size of 2.300". Even in our 900 hp drag motors we use 11/32 stems. So we are reducing the diameter of the valve by .100" and only reducing the size of the stem by .015" per side. In my opinion not significant and will provide adequate durability.
Guys, in all out everything goes, class driven, weight restricted, SANCTIONED racing applications, grams I'm sure are worth fighting for. And yes weight = parasitic drag. I think the issue is really not worth the time being spent on it... Why then did GM do it? To wring every inch pound of torque and power out of the motor so they could stake the claim as having the first production car motor with 500+ horse power (505 I believe was reported).
I hope this helps.
B


Thanks for your input.