Front brakes and the LQ-2

[RocketScott]

'89 Pete 379, Cummins 444xt...

After getting my front brakes back together I fired the truck up to move it back to it's usual spot. When I applied the brakes I started losing a ton of air. The valve that splits the air at the front was just dumping air out of the exhaust port. Took it apart and it's toast, the seals are all hardened and cracked

After some poking around the web I figured out that it's an LQ-2 valve. The description says that they were used on 'pre FMVSS-121' vehicles. I've got a switch on the dash that says "slippery/dry" that cuts the front brake application by 50% when the roads are slippery. My front brakes haven't worked since owning the truck so I have no idea how well this system actually functions. I do know that they don't set trucks up like this anymore...

So my question is: Do I just replace the valve with the same or should I upgrade the front braking system to something closer to current standards (but without installing a full ABS system)?

Not sure if there's a better way to proportion the braking between front and back without going full ABS