I just got another PM question about this subject again. I've probably already put a post in for this in this thread but it can't hurt to put it in here again:
You can use the adapter sleeves to mount the S10 spindles but there is a potential for extra neg. camber. The problem comes from a difference in the location of the LBJ mount on the S10 spindle. The LBJ mount on the S10 spindle is 1/4" offset FROM the spindle. This moves the bottom of the spindle outward by 1/4" causing an increase in neg. camber. This is fine for a road racing car but not so good for a drag car. I know a lot of guys have successfully used these with out any problems. I'm not a big fan of them but I'm working on a road racing chassis and I like the extra beef in the S10 spindles. For a drag car that will not see many corners the adapters should be fine. The other problem is that the h-body ball joints are slowly disappearing and they are getting really expensive. The S10 BJs are plentiful and will be for a long time.
That brings us to S10 BJ swaps. There are a couple factors to consider when deciding whether to go with the S10 BJs or not. The swap to S10 ball joints has some complications. There is no prefab LCA for the S10 ball joints so you have to fabricate your own solution. I cut out some s10 sleeves from a couple junk LCAs. THat was a lot of work. You can buy weld in sleeves for the Vega LCAs from UB Machine:
http://www.ubmachine.com/When you mount the sleeves they need to be welded 1/4" inward to account for the camber issue. You can modify the UCA for s10 ball joints. I tried this. The problem is you need to mount the BJ as far out and back as you can put it and still mount it. The reason for this is that the stock UCAs put the caster pretty close to zero. That's a problem in a drag car. That is compounded if the rear of the car is higher than the front. It may even put the caster into the neg. area and that's a dangerous place to be for drag racing… well for anything in my opinion.
That brings us to the adjustable UCAs. Not a cheap solution but I think they are totally necessary for motorsports applications. This way you can adjust for camber and caster at the track then put it back to more streetable settings when you leave. It is possible to get extra neg. camber by using the stock UCAs but you can't get the extra safer caster. Built in extra pos. caster makes driving on the street a little harder especially if you have manual steering. If you get some of Chuck's adjustable UCAs, just be sure he's checked the parts. I had one of the sleeves that didn't have the hole drilled all the way through. I had to drill it out myself. No big deal but it took me a minute to figure out what the problem was. LOL!
They are relatively inexpensive compared to custom fabrication and pretty easy to install. Good stuff. Thanks Chuck.