3-angle valve grind vs. "standard"?

[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.

[Aurora40]

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]

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]

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]

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