I have been running the ACL pistons for several years. They have held up very well. The only issue I have seen is I get a bit of piston slap when cold. Totally agree on the Hastings rings. Their chrome ring works very well. On the second ring make sure you check the ring groove depth if you use them on ACL pistons.

ACL and Clevite have good bearings. For the balance shafts I really like the ACL that don't have a parting line groove. DONT use a grooved balance shaft bearing.

If your 84 has the giant pot type manifold I would get the 87 and later unit and run it with a converter under the truck. It's a TRI=Y setup with a nice broad power band. If you go with a header look for one that similar to the factory cast part.

Kevin