Long story short. The truck came with a 350 TBI, now has a 400 with a carb. I took the computer out and it no longer switches to the 2nd tank. I know I can buy the carb version of the valve for about 70 bucks from GM dealer. Just curious how difficult this job would be and would I have to change the switch in my dash because of any wiring changes. And do both versions have the same amount of inlets/outlets to them? I'd love to hear your 2 cents.