Late A/G body question...sort of

[jaybee]

The Saginaw 605 steering box had been the unit of choice for 55/56/57 Chevs until just recently when new boxes based on the 600 box hit the market. They've always been a bit problematic in the Tri5s, however, with a reputation for being over assisted. It seems a little odd for me, though, considering that the 605 worked just fine on huge fleets of Malibus, Monte Carlos, and derivatives, as well as scads of low-level stock cars. Even taking into account the 1970s tendency toward very light power steering there must be more to it than that. Why does this unit work in one car but not the other?

[Derek69SS]

I'm not familiar with the steering setup on a tri-5, but it could have something to do with steer-arm/pitman-arm lengths, or perhaps they just can't align them with much, if any positive caster... more positive caster requires more steering effort, but in turn gives you better stability at speed.

[jaybee]

How much caster can you get in an A/G body? It is hard to get much caster in a tri5 without aftermarket upper control arms, offset control arm shafts, or modifications to the upper control arm mounts.

[Derek69SS]

The only one I've aligned with stock arms I was able to get +2.5... no room for any more shims, and the arms were getting very close to the smallblock headers.

It will vary from car-to-car as the factory tolerances were not very tight... heck it varies from side-to-side even on the same car. That car I could have gotten +3.5 on the drivers' side, but the passenger side I could only get +2.5.