70 chevelle rear and front lower control arm bushings

[70chevellemalibu]

Im rebuilding my rear suspension and i will simply be boxing my factory stamped control arms to save some cash, now I thought i read somewhere that I should not use Polyurethane bushings in the rear?

Also up front I have bought UMI upper adjustable control arm with a .9 balljoint and a .5 lower ball joint, again to save some cash at this point i will be using my stock lower control arm, what bushings should i use in them?

I the car will be an aggressive street driver with the mild autocross session.

Thanks.

[70chevellemalibu]

nobody knows?