Howdy folks, I'm new here and just wanted to say hello. I joined because I picked up a 93 GMC Sierra 1500 ext cab 2wd that just turned over 270,000 miles, mainly for hauling water to fill our cistern water supply (we are really rural for east of the Mississippi, have no public water on our road, and the well water is unfit due to the surrounding coal mining/deforestation) but we also use it for general hauling duties and lately it's my daily driver because my car is awaiting repairs. Anyway, I have some questions and repairs needed that I thought I might find out the info in the GM dealer service manuals. Well, they are less than totally helpful (compared to the FoMoCo manuals I have for our cars). I hope folks here can help me out a bit. I would spend countless hours here researching but my only online access is the hour I get at the public library about once every two weeks when I go to town. Here's my issues for now... I get a knocking noise from the heater box when I first start the truck and when I turn it off and when using the max a/c, it lasts about 30 seconds and then stops, I assume it's a vacuum to a recirc flapper in the air exchange box, any ideas on a fix? My trip odo doesn't work, at all, won't reset, won't roll. Oil pressure always reads at the top of the scale when running but returns to bottom when not running (this might be the engine issue, see below). The previous owner (2nd owner I believe) kept impecable records (even every fill up of gas with milage) amd says he had a GM Performance 383 long block installed, it does have an Edelbrock intake, K&N filter/intake tube, and chrome oil pan. How can I confirm this? What are the capacities and tune up specs for this engine? I think this may be the oil pressure gauge problem and I'd like to do a tune up on it and would like to get the right plugs and gap. I bought a radio install kit off ebay and had no instructions, can anyone send me them or a link to them? I'd also like to replace the original speakers with 4x6 plate separates and add a smallish sub, does anyone know of a cheap under rear seat box or DIY for one? The previous owner had this truck set up for towing a large camping trailer but it was only a 1/2 ton truck, he put on larger tires I think them are 32 x 11.5 and put in rear axle air bags. The air bags are nice and I can easily haul 425 gal of water in the back, but I'd like to ditch the big knobby tires for ones more suited for the highway (lower noise and better milage). I'd like to know if I can just get a set of 3/4 ton springs and swap them in to this chassis? It has what I think is a stock PS oil cooler that is leaking bad some\where, any clues on a fix? The local parts stores dont offer the hoses for this setup and the dealer killed me on the gas line I replaced myself ($130, ouch!). btw, I replaced the gas line between the filter and TB, GM manual absolutely no help, but not a hard repaire once I got my old self under the truck. I'd like to swap in a set of newer seats, these are OK, but I'd like to get the flip down center console or bucket style power seats. Anyone know what years swap easily? My headlights are yellowed, I know I can buff them but that doesn't last long. Does anyone have experience with the ebay replacements? Does anyone make these in glass (like for the European markets)? Sorry this is so long. Thanks for any help you can give. Bill.