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Old April 7th, 2017, 05:28 PM
POWERSTROKE POWERSTROKE is offline
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Default Re: Lowering a gmc 4000

Wow, I'm surprised there's so little clearance between the frt axle and oil pan. The C65's I drove with 366 big blocks had 10 inches. There was a couple others, a 350 truck engine and a 292 but I never spent any time under them. Trucks all had 12,000# axles. There was a little C-50, a '67 to '72 vintage that I drove quite a bit, it felt overloaded with 4000# in it. Straight 4speed, was a 350 but it was over-reved and blew up, guy used up ALL the 305's around trying to keep it on the road. Guys would wind it up to 60-65 and it would last 500 to 1000 miles. Owner even blew one engine! I bet I put 5000 miles on it just running 50-55 mph. The other truck I drove was a 1900 FleetStar Binder with 478 V-8 and straight 5-speed geared to run 62-65 with a 45 ft trailer. It was a little overkill for 2-3 skids of freight!

Can't really say what the GMC V-6's got for mpg vs other V-8's. The V-6 GMC's I rode with Dad in carried over 125 gallon of gas, longest run was around 350 miles so never had to buy gas on the road. The 478 V-8 Binder got around 3 to 3-1/4 mpg. It had two 50 gallon tanks and my normal run was 175 miles plus some running around town on both ends so 400 miles or more. I bought 60-65 gallon of gas and a quart of oil on both ends. With the early '80's F-700 Ford with Detroit 8.2L Fuel Pincher with a single 40 gallon tank I bought $20 of fuel every night to make sure I got home, Boss gave me $100 every Monday. That 8.2L lived up to it's name, got 7 to 7-1/2 mpg! The first night I got home with the Binder and only had change left from his $100 he almost cried!

Yes, there are lower profile tires that should fit your wheels. A narrower tire would be smaller in diameter too. A good truck tire shop should be able to fix you up. Have to laugh now, company I drove for used up all the cheap 10.00x20 recaps and used tires, and 11.00x22.5's. One morning I hook to a loaded trailer and do my walk around and thump tires, the one side of the trailer had two 9.00x20's mated to 10.00x20's, the 9.00's weren't even touching the ground! The 10.00's were carrying all the weight. They would last 40-50 miles of my 165 mile trip! I had the grumpy tire guy change them, mate the 9.00's together and the 10.00's together. I think that was the day I had TWELVE TIRES put on my tractor & trailer or had them blow before I got to my destination. A personal record!
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