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David 01-06-2007 08:15:48 68.241.184.192 23030 Report to Moderator	I just bought a 1971 F700 with a 390 v-8 and a five speed. The motor appears to run ok but it seems odd that is would be a two barrel carb. It seems like it struggles to go 40MPH unless rolling down hill. It has a 20ft steel Flat bed. Does anyone know if this type of truck should go faster? It seems crazy that it slows to 30mph going up hills. Any good sites to get info on the factory specs or any info on this type of truck?. Thanks. [Reply]  [Send Email]
Hal/WA 01-06-2007 17:41:23 66.45.175.118 23045 Report to Moderator	Re: 1971 F700 Does it go over 40MPH in reply to David, 01-06-2007 08:15:48   If it struggles to go over 40 unloaded, I would suspect a problem with the tune-up (maybe stuck advance plate?) or maybe a plugged exhaust system. If you have a tach, that engine should rev fairly easily, and I would expect it to have no problem going over 4000rpm. A friend of mine had a 68 Galaxie with a 302 that got rotten gas mileage and would not go over about 70mph. He had the problem analyzed and learned that the exhaust system had collapsed inside. A new muffler and tailpipe upped his gas mileage by about 5mpg and his Galaxie would exceed 100 with ease. If the engine is screaming at 40mph, at like 3500-4000rpm, then it may just be geared very low. Or, like the others wrote, you might have a 2 speed rear end in low. Lots of the old grain trucks had very low gears, and worked pretty well with 6 cylinder engines, for the purpose they were built for. But those trucks were not intended for ever going fast. My 36 Chevy was flying at 45! And I think that trying to go faster downhill might have blown up the engine. But I would expect a truck that new, with a fairly large V8 engine to be built to go down the highway at a decent speed. But all sorts of rear end ratios could have been ordered...so you probably want to check what you have. Good luck figuring it out!   [Reply]  [No Email]
1952henry 01-06-2007 08:20:39 71.221.88.163 23031 Report to Moderator	Re: 1971 F700 Does it go over 40MPH in reply to David, 01-06-2007 08:15:48   With the two speed axle in high, it should go at least 55 mph. As a teenager I drove an F600 tandem with a 330ci and 4 speed. In 4th high it would go 70-75. Even at 46,000 lb gvw she would hit 70 if given enough room on a flat.   [Reply]  [No Email]
David 01-06-2007 08:28:59 68.241.184.192 23032 Report to Moderator	Re: Re: 1971 F700 Does it go over 40MPH in reply to 1952henry, 01-06-2007 08:20:39   Thanks for the reply. I'm pretty new to the big truck thing so bare with me. When you mention a two speed axle how does that work exactly. Should I have a High/Low lever in the floor or somewhere. When I shift out of 3rd into fourth it does seem to have a pretty high gear but the truck just does not seem to want to pull at all unless on level ground or down hill. I bought it on ebay the link should take you to it. Any other info would be great.   [Reply]  [Send Email]
Bob 01-06-2007 09:25:21 69.178.229.154 23034 Report to Moderator	Re: Re: Re: 1971 F700 Does it go over 40MPH in reply to David, 01-06-2007 08:28:59   On a truck that size, IF it has a 2-speed rear axle, most likely the shifter for the axle would be mounted on the gearshift lever. The truck may have been set up without a two-speed rear axle, or the shift switch may be missing. Take a look under the truck (be safe... lock parking brake and chock the wheels). IF it has a 2-speed rear axle, there will be an electrical cord from up in the frame, down to the electric shift motor on the rear axle. (Older trucks, and SOMETIMES trucks of that age sometimes used a vacuum axle shift... if your's is set up like that, there would be a large diaphragm unit mounted to the rear axle, with one or two fairly large vacuum hoses running to it.)   [Reply]  [No Email]
David 01-06-2007 08:36:22 68.241.184.192 23033 Report to Moderator	Re: Re: Re: 1971 F700 Does it go over 40MPH in reply to David, 01-06-2007 08:28:59   Not sure if the link showed up http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190067826773   [Reply]  [Send Email]
Tilar 01-08-2007 20:04:03 24.164.107.72 23106 Report to Moderator	Re: Re: Re: Re: 1971 F700 Does it go over 40MPH in reply to David, 01-06-2007 08:36:22   If that is the truck and you are looking to buy it, I'd have the guy take you out and show you what is up.. He advertises: "At 60 mph it drives perfectly straight"   [Reply]  [No Email]