LT1 Valves??
 

I have acquired a set of bare NOS aluminum lt1 heads that i am planning on using for an lt1 buildup, i plan to get the heads ported and before i do i wanted to get the seats ground down to except bigger valves, what is the biggest valve sizes that can be run on a stock heads and what length should i get, i am gonna be running a custom ground cam, so would there be any advantage of running longer valves? Or stick with stock length.

2.00/1.56 fit the stock seats and WORK. Don't make "bigger is better" mistakes in your build.

Wether you want longer valves will depend on the springs you want to run and the springs depend on the cam.

1.94/1.50 is stock size and you can go up to a 2.00/1.56 with the stock seats if machined for them. Anything larger will need larger valve seats installed.

Most use the 4.911" long Manley 11500/11501 ($200 thru Summit) or 4.960" long Ferrea 6161/6165 ($250 or so and hard to find a supplier for average person).

These lengths mentioned can be set up with just about any spring to handle a hyd roller and alot of solid rollers.

Lloyd

So you would recommend using 4.911 inch valves for both intake and exhaust.

yep, plenty long enough for just about any normal spring set up.