Sorry, got lots of questions/thoughts lately.

I am putting Speedway tubular control arms (upper and lower) on the 79. The uppers use a non stock bushing and Speedway doesn't offer a poly version, only rubber. 
However, it appears that the lower control arm uses the stock Pinto/MII bushing, and there is a poly bushing for that from Energy Suspension. At least Speedway's dimensions and Rock Auto's dimensions are the same.

I really, really, want poly. However, I am not sure if mixing rubber uppers and poly lowers is a good or bad thing. I wouldn't think it would hurt anything, but I am not an expert on this stuff. I don't mind paying for a whole poly kit just to get the lowers if I have to. Maybe someone can use the uppers.

Thanks,
Russ