3-angle valve grind vs. "standard"? - ZR-1 Net Registry Forums

Paul Workman · 10-01-2009

Just getting my ducks in a row in anticipation of a valve job on my baby.

Any ideas on what a 3-angle valve job is worth in HP gain vs. the standard fair, as it relates to a 485-500 hp LT5?
And, would a 3-angle grind usually be accommodated with new guides as well?

And, one un-related Q regarding the TB: What are the real gains from porting the TB on an otherwise fully ported 350 LT5?

TIA,

P.

Aurora40 · 10-01-2009

I can't answer your questions. However, if you weren't sure you wanted the time/expense of the TB, you could always do it later.

You can look at the MAP readings while at WOT, and see how much they drop as the revs climb. If it drops more than normal, a larger TB may be of benefit. If it doesn't, it probably won't be.

Ccmano · 10-01-2009

Quote:

Originally Posted by Paul Workman

And, one un-related Q regarding the TB: What are the real gains from porting the TB on an otherwise fully ported 350 LT5?
P.

I believe Jeffvette and Haibeck (although Haibeck does include it in his basic package) claim it is not worth doing on a 350ci engine, you need more cubes to take advantage of the added air flow.

H

flyin ryan · 10-01-2009

Quote:

Originally Posted by Paul Workman

Just getting my ducks in a row in anticipation of a valve job on my baby.

Any ideas on what a 3-angle valve job is worth in HP gain vs. the standard fair, as it relates to a 485-500 hp LT5?
And, would a 3-angle grind usually be accommodated with new guides as well?

And, one un-related Q regarding the TB: What are the real gains from porting the TB on an otherwise fully ported 350 LT5?

TIA,

P.

Way too many factors to come up with a HP/LBS. FT. 'Gain' number, if anyone gives you one they don't know what they are talking about or are guessing.

Should at least check the guides, the more true the guides are, the better & longer concentricity will stay with the seat/valve head relationship. Sounds like crap but can't think of a better way to explain right this second...

.

TB? Very little...again very tough to come up with any kind of 'Real' number.

RE: V/J...do a 'Full' radius valve job on the exhaust, no cut's or have it cut then blend to a full radius, if your able, it's worth it.

blackjack · 10-02-2009

a 3-angle valve grind is the standard these days...a real performance valve job has 5 angles...
as an exemple,on a twin cam harley head,a 5 angle job gives me 3-4 cfm more than a regular 3 angle one.the difference is more obvious at low lift,where the air is ''pushed '' on the seat by the intake valve being in the way
bj

10-01-2009	#1
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	3-angle valve grind vs. "standard"? Just getting my ducks in a row in anticipation of a valve job on my baby. Any ideas on what a 3-angle valve job is worth in HP gain vs. the standard fair, as it relates to a 485-500 hp LT5? And, would a 3-angle grind usually be accommodated with new guides as well? And, one un-related Q regarding the TB: What are the real gains from porting the TB on an otherwise fully ported 350 LT5? TIA, P. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry

10-01-2009	#2
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,713	Re: 3-angle valve grind vs. "standard"? I can't answer your questions. However, if you weren't sure you wanted the time/expense of the TB, you could always do it later. You can look at the MAP readings while at WOT, and see how much they drop as the revs climb. If it drops more than normal, a larger TB may be of benefit. If it doesn't, it probably won't be. __________________ Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img]

10-02-2009	#5
blackjack Join Date: Aug 2005 Location: north of montreal Posts: 510	Re: 3-angle valve grind vs. "standard"? a 3-angle valve grind is the standard these days...a real performance valve job has 5 angles... as an exemple,on a twin cam harley head,a 5 angle job gives me 3-4 cfm more than a regular 3 angle one.the difference is more obvious at low lift,where the air is ''pushed '' on the seat by the intake valve being in the way bj