The improvement no doubt due to the fact that when the battery was put in backwards, the coil polarity wasn't changed to correspond.

Unless you're planning on adding non-authentic electrical accessories that require negative ground, there really is no advantage to having it; if that's the case I'd return it to the correct positive ground.

Rebuild kits have pretty much dried up some years ago, to the extent that the production rebuilders have their own parts made. I've had excellent experiences over the years with Art Gould, now d/b/a Gould Rebuilders. They're a regular advertiser in most hobby publications and are somewhere in New York State as I remember. Probably cost about $85 or so and a better job than you could do yourself.

To do a proper job, you remove the counterweights from the crank before grinding. They are bolted in with extended head bolts and after tightening the protruding head is cut off and welded. So to remove you have to mill the bolt head from the countersunk recess in the weight. Make new bolts and reverse the process to reinstall, then balance the crank.

Kevin, in those few cases where I've taken note of an inlet restrictor, it's in the inside orifice of an otherwise standard looking brass elbow. No difference from one you buy in the hardware store until you peek inside.

Can't tell for certain w/o a side or interior view, but that piston just above looks like an autothermic strut piston and if so, it wouldn't need a "T" slot, just a simple expansion slot. This type of piston uses a steel strut separating the skirt from the head, the benefit being that the head, which runs the hottest, is somewhat insulated from the skirt and thus tighter skirt-to-bore tolerances are possible, running quieter in part by eliminated piston slap when cold. Perhaps the strut also somewhat controls the expansion characteristics. Cast and forged pistons are normally one-piece affairs and as the heat from the head travels more directly to the skirt, the skirt runs hotter, expands more, and requires more clearance when cold-fitting. At least this is my understanding of the matter.

Sorry, I'm not at all familiar with the Willys, Studebaker and Chrsyler engines and was thinking Packard pretty exclusively, though I didn't say so. Sorry 'bout that. But let me quote again an excerpt for the 33/34 Service Letters:

"Up to and including the Eighth Series motors this slot was on the left hand side, that is to say, on the same side as the oil filler. In the Ninth Series and in all later series the slot faces the valves. Either the early or late motors will operate satisfactorily with the slot on either side but we believe the present construction with the slot facing the valves will probably give a little quieter result and a little longer life. Either installation however might be used when fitting new pistons in the earlier blocks, and there is nothing incorrect in installing all pistons with the slot facing the valves."

I've always found GM's failure to adequately engineer their early air suspension system for cars a curiosity as they already had an air bag system system on their Yellow Coach (bus) division in service which gave admirable service and according to some retired bus mechanics I've spoken with was very trouble-free. Perhaps they just went a bit too far on cost minimization.

I believe that all Packard in-line Eights were 9 main bearing engines until the advent of the "120". Also in rebuilding you might want to take note that Packard had a change of heart about the positioning of the connecting rod bleed hole, this is covered in the 33/34 Service Letters. To paraphrase, "prior to the 9th series motors the connecting rod oil bleed holes were on the "leading" or oil filter side of the engine; starting with the 9th series they face the valve-side and subsequently the size of the bleed hole was reduced in size from a #30 to a #56 drill size for better oil control. However the rods shouldn't be switched in the earlier (than 9th series) motors because the bleed holes will not align with the crankshaft at the proper timing."

Just a note on pistons, the originals were "autothermic strut" design which have entirely different expansion characteristics than cast or forged pistons. When using replacement pistons, the original Packard piston skirt clearance specifications should be ignored and those of the new piston make used. Cast or forged pistons also require different clearances. Expansion slot on the valve side of the engine is the general rule for L-head engines.

I've got the installation diagrams that Packard provided with the factory accessory filter kits supplied to dealers for installation on cars that were factory-shipped without them (generally, the non-hydraulic lifter models). The diagrams are a bit crude but if you want a copy, send me a PM with your email address and remind which you want, 48-50 or 51-54.