Buying new valves..what would be best and are 516 heads any good?*update*

[greenpigs]

I am going to get a set of 906's and have new bronze valve guides installed, so I figured to put some new valves in. Are under cut or "light weight" ones worth the extra coin?

Mostly stock low cr 440 in a 69.

I am not going to port the heads as I learned my lesson on doing things on my own.

BTW I can't believe no one has asked yet..I did a search.

[firefighter3931]

If you're redoing the heads and want to upgrade, just go with the bigger 2.14/1.81 valves. Have the machine shop do a 75* throat cut into the bowls when they're cutting the new seats and just blend the throat cut into the bowl. Voila, bowl ported heads that flow waaay better than stock. 

The throat cut makes the porting templates obsolete and saves you a bunch of time. These types of mods will show a 50hp increase (or more) depending on the rest of the combination. 

Mancini carries the hardware you'll need at a reasonable price. For $225.00 you can get 16 oversize stainless steel valves, chrome moly retainers and 10* locks. All you'll need is a set of valvesprings matched to your cam profile. If you're going hydraulic on the cam ; the comp cams # 911 spring works well for almost any application and the set goes for around $90.00 or so.

http://chucker54.stores.yahoo.net/bststsigrwic.html

http://chucker54.stores.yahoo.net/comcambrbhig.html

Ron

[greenpigs]

YOU DA MAN FIREFIGHTER!!!

  I chocked a little when I looked up valve and the cost but oh well. I have a set of MP valve springs that are replacements for the stock size cam a 69 440 came with. I run a summits cam with similar duration and lift. 272\282  .442/.465 gross.
 
  I might go with the comp springs and put the other ones on the 516 set of heads I will be getting.

Another question.

  The 516 heads bump the CR about one point but I have heard they do not flow that well so the gain in cr is kinda offset by that. Would I be better off getting the big valves put in them and the 75* cut along with new valve guides(assuming they need it) in the 516.
  I run a 72 440 with a virgin bore and the stock pistons. The block was not decked and I plan on using the thin MP heads gaskets. Also I am using shims under the shafts and I might have to swap those out or just go without them as I can't find the other sizes.

[firefighter3931]

With a low compression engine, i would probably opt to go with the 516's to gain some added squeeze. The 72 motors are in the low 8's for compression so anything you can do to bump it up will help. Those Summit cams are descent and work very well. 

The biggest gains with oem iron heads for lifts less than .500 is in the bowl area. That's where you need to focus your attention, inmo. I would still do the big valve upgrade and blend the cut into the bowl. Those Valvesprings would probably work but you should have the pressures checked to make sure that they're compatible with your cam. Have them checked for seat pressure (installed height) and spring rate (open pressure). Also have them checked for coilbind...you need .060 past max lift.


Ron

[Chryco Psycho]

I have often used 516 heads & with porting & larger valves I have seen no loss in power using them over 906 heads , personally I like the closed chamber better