Put a down on an 86 Burb!

[dmsteele92831]

Just put a down on an 86 burb. Got a really good deal on it too! It's a 4X4 3/4 ton, originally a diesel but the owner swapped it to a 350 and there a rebuilt turbo 400 behind it (nice thing is NO smog). Has dual exhaust, 4" lift, and a new 650 Edelbrock carb. Has a new alternator, distributor, plugs and wires. I'm going to change out the oil and all the differential fluids as soon as I get it on Wednesday. What weight should I use on the oil? (Both on the engine and differentials). I will be towing on occasion so I want to use synthetic. Can I just use 75W-90W on the front and rear differentials and the gear box? Also, when I turn on the lights it makes a buzzing sound. The owner said because there's a light out somewhere??? Does that sound right? I'll post pics here within the week after I get it washed and waxed.