Couple quick questions...
 

1985 GMC High Sierra LWB, 350 Engine code M.

What is the correct gap needed on the spark plugs? I've seen .030, .035, and .045 listed on different sites.

Also, What is the difference in all these spark plug wires? They range in price from just the Belden wires from $34.39 to $116.49. I don't plan on buying anything but the minimum but was wondering.

And last, what is the correct temp I should get for the thermostat? I've seem OEM at 180, and 195.

Thanks

Re: Couple quick questions...
 

Anything with an hei distributor should be .045 plug gap. .035 is for points which havent been used since the mid 70's in gm stuff. Buying a decent set of wires is a good idea. The price difference is the quality of the wires. I would reccomend a set of taylor wires for about 60 bucks. They will last 2 or 3 times longer than those pos belden wires could think of lasting. The better wires have less resistance and better insulation. Less resistance means more spark gets to the plug and the better insulation stops the spark from leaking through the wires causing misfires or running problems. Generally a 195 thermostat is what should be used. Thats what it came with. The engine coming up to proper temp is neccessary to burn the moisture out of the crankcase. Engines that dont come to temp tend to sludge up especially when only driven on short trips.

Re: Couple quick questions...
 

Thanks cableguy0. I will step up and get better wires. My truck doesn't get up to temp now so I need to switch it out before I try to retest for smog. Now I just need the time to do it.