If all you want to do is an axle flip, Dexter makes a under/over kit for underslung axles to move the spring pack from the bottom to the top. There is no need to have to buy a whole new straight axle. This link is to Etrailer.com which is one place that sells the kit. This is for a 2 3/8" diameter axle tube. If yours is smaller than that, then it will not work. But there are many good pics of the conversion so you can see what this is all about https://www.etrailer.com/Accessories...71-384-00.html
But, since you have a 1979 camper, a new axle, and being straight can add some benefits.
1. Yes, it will raise the camper
2. You can order it with new current day brake plates and drums if needed. Some of the older campers have obsolete brake systems and getting parts is hard to impossible in some cases. You can get it with new springs too if wanted.
There is a very different cost in parts between those two options. If you are hiring the labor out to do the work, changing a complete axle with new axle unit may be very close to doing the over/under kit.
Scott was correct on the measurements you need if you go that route.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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