I know the LT4 had some really light valves and I just may have to buy a set when I go to a 350 and enlarge the valves on my heads. The 2.00/1.56 that the LT4 uses won't fit in my 305 I don't think.

Are there any sets of valves that I can get for less than $100 that are lighter than stock?

 

When I did my valve shopping for my old AFR heads, I found Manley Race-Flo valves where the lightest non-Titanium non-hollow pieces around.

 

Hmm the stock LT1 valves I have for these heads.. the 1.94" weighs in at 110g, and the 1.50" valves weigh in at 95g. Whereas the LT4 2.00" weighs 85g, and the 1.56" weigh 75g. They are hollow though, with the exhaust being sodium and potassium filled.

The Manley ones are 89g for exhaust and 107g intake (1.94/1.50). Not a big enough difference for me to go with. I may just stick with the stock ones until I get the heads re-cut for larger valves and go with the LT4 valves.

Do the undercut/backcut and polished valves make a big difference in flow characteristics?

 

Yup, agreed the stock GM ones are a good cost/weight balance. I found much more variation on the open market...Ferrea and some other valves same size as Manleys were double-digit grams heavier than Manleys.

As far as the valve head/stem area geometry, both Vizard and some other engine book I have indicate the undercutting is a good thing. No recorded instance I could find of an unmodified Manley valve snapping a stem.

 

Oops edited my post before you finished replying

Hard for me to justify the extra $170 cost of new valves that won't have a noticeable difference in weight. Like I said, I think I'll just hold off and use the stock ones until I swap a 350 in. Then I'll go to the slightly larger and much lighter LT4 valves. The LT4 intake valves are 25g (22%) lighter PER VALVE, and the exhausts are 20g (21%) lighter. That's a very big difference.