A friend of mine has 5/8 tubes and rod heims on the front and rear of his modelA and says they work fine. He does say that the heims chatter while goin down the hiway but he lubes them every trip to help with that. He puts on about 2000 miles in a summer. I also talked to a racin chassis builder friend of mine when I was considering using the swedge tubes and he also asked about engine hp and tire size. I'm gonna run a 9:1 355 chevy and
G60 or N50 tires. He said to run no less than a 3/4 swedge tube and heim setup, he said that would be as strong as chrome moly tube and be less expensive. With more than 35 yrs of buildin and racin modified racecars I believe in what he tells me. I'm gonna try it and see how it works, not worried about it.