[Grim Reaper]

What is this 250 6 that you speak of?


HAha

Well that's a hard call. Some models had different ratings. A Cali destined truck had far more emmisions the the rest. My 79 350 Blazer had EVAP, CAT, EGR, Thermac, PCV and restrictor neck in the fill tube for Unleaded only.

My 75 has a PCV and Thermac. No problems passing when I still had to smog that truck. Internett buddy in Cali with same model truck made in 74 had to have EGR, Thermac, cross over heat riser flap, PVC, and I think EVAP But I don't think he had to have a cat.

I know some trucks had AIr pumps.

Is the Emissions sticker still on the core suport? That would be the best start as to what it had.

I would say at the very least your going to need EVAP, EGR, PVC,THERMAC air cleaner and CAT. Look at the exhaust manifold if you know it's original and see if it has a place for AIR. Now just because it has them it may not have been equiped with it. They may have had plugs. That sticker if present will show the control Vac lines if it had it.