This is indeed the season to thank HH56, as the others have above, and at the risk of diminishing Howard's praise, include Owen_Dyneto, Peter Packard, and Tim Cole, as founts of encyclopedic wisdom.
A happy Christmas, smooth 2016 to these gentlemen so generous with their time and knowledge, to all those who visit PI,
and, of course, BigKev, who started it all.

I think Oz is right, since the 288/327 junior tubs were originally so tired, 7.60/15 a popular size for mid-range cars in the late '40s, shared with Hudson and others.
Check with a knowledgeable, longtime tire shop and see if the above 7.00/15 radials i mentioned will work on your wheels. Part of what gave Packards the best chassis in the industry was having sturdy wheels. So better to over- than under-tire, especially given the bathtubs' heavier weight, and that they were marginally tired even when new.

I recall seeing the corresponding 1947 Cadillacs to my '47 Super Clipper had but a 4.5-inch-wide wheel, while my car has 5.5-inch width wheel. That's what Packards are all about,
lost on most people as they headed for the hipper, slicker marketing, styling of GMobiles while Packard, spoiled by wartime profits from open-ended contracts from a seemingly bottomless Federal government, understandably focused on more lucrative jet engine contracts instead of capricious retail customers and whiny dealers, increasingly phoning in the cars, limping along after GM, East Grand otherwise toast by the '40s, being run by the B-O-P men recruited in '34 to show them how to cost the 120.

Crewe knew how to focus on aero engines while marketing boutique cars. Packard, well: Woulda, coulda, shoulda.

See if your woody'll take a set of Bridgestone R230s. It should handle very well -- better than before.

Get a set of Bridgestone 7.00 x 15 R230 LT radials, or the Yokohama equivalent, identical specs the latter, also available at a hefty premium from Diamond Back in South Carolina, if you feel the need for added whitewalls, which many owners in the day thought gauche, tacky. The beauty of these tires is that they come in our 7.00 x 15 bias ply size, and so look right in your fender opening, while giving you all the advantages of radials. Remember, Packard built cars, not batteries, generators, motor oil, brake fluid, tires.

Diamond Back offers, last time we checked, whitewalls vulcanized on Yokohama 7.00/15 bias-sized LT radials, as well as the usual SUV metric radials, which most people use despite not looking right in the fender openings. Only one car in 20 or 30 at any price level had whitewalls in the '30s, '40s, and dear few had fog lights, but that doesn't stop those today allegedly concerned with "is this correct" and scoring points. That the CCCA, PAC and others award perfect scores to 1946-47 cars with whitewalls unavailable when new underscores this mentality. Or gloss-painted engine accessories which were originally matte or semi-gloss black.

Don't take any nonsense about "truck tires" from the same people running 225/235/15R metric SUV tires on their Packards, since big SUVs are built on pick up truck chassis.

Michelin also offered 7.00/15 LT radials per above, identical specs, until the early aughts. Unfortunately, only a few savvy 1941-on Cadillac, Buick, Packard owners knew about them, there otherwise a small market, so Michelin bowed out.
If we don't patronize Bridgestone, Yokohama, we'll be dead in the water, forced to buy bias plies people in a third world wouldn't use, or else metric SUV tires which simply don't look right.

Again, as per Diamond Back, you can vulcanize a wide whitewall on anything, but a good design doesn't need tacked on ephemera, most high-end, top-line cars were free of such dreck originally. Similarly, you rarely saw fog/driving lights on cars in the '30s, '40s, but tell any of this to gotta have it clubbies today and watch the fur fly.

The above's good advice and how my '47 Super's 356 is; black intake, Eastwood silver-gray exhaust.

Adjoining subject, wonder if the reason Packard didn't porcelainize their 1940s manifolds was for better heat dissipation? The 1936-48 Cadillac flathead 346-ci V-8 had porcelainized exhaust manifolds, as well as an antiquated, 1930-style water pump, for that matter.

Or was Packard just cutting cost? They were up against the ropes vs. the slickly marketed Buicks, Cadillacs, GM already having lower unit costs, despite the former B-O-P production men brought in for the 120 now running the show.

Not concerned whether we like or don't like porcelain, how it holds up then or now, just wonder whether an engineering or cost decision---or both, for Packard to have omitted it.

Again, OD gives good advice. I doubt a wash of the Eastwood product much impedes heat dissipation, and certainly looks better than a raw log of cast iron.

Further afield from the poster's question, always thought it interesting that Cadillac and Packard shared such close shades of deep green engine color, wonder why one didn't sue the other.

Thanks for any corroborated insight, not hunches, guesses.

Still wonder, as i did here years ago, if there are any SAE or other impartial papers contrasting, comparing the 356 w/ the 346, or Buick's ohv 320. We seem to be shy on vetted historic insight on these forums, long on Monday morning quarterbacking and fantasy cars.

Despite only another 10 cubic inches than the concurrent Cadillac, the Packard 356 puts out a bit more torque and considerably more real world hp. Skip the advertised figures for both, which are inflated, as were all ad hp even then, according to exhaustive dynamometer tests of every domestic 1940 engine by Buick engineers other than the lowest-priced cars which weren't seen as competition, Flint's advertised hp being closer to the truth than most others, Cad and Packard included.

The 1941-47 Cad 346 had a high for the day 7.25:1 compression against the 1942-47 Packard 356's 6.85:1. So wondering if inline sixes and eights being the only engines in natural, inherent balance allowed Packard to run a slightly hotter cam than than the Cad without sacrificing the smoothness, unobtrusiveness Packard customers expected? Again, would really be swell if someone could dredge any period 1940s SAE or other objective papers, assuming there were any.

Meanwhile, back to porcelain and thanks again for anything factual.

It's there for a reason, and helps in any climate, tho' obviously more important in Duluth. First, make sure your thermostatic spring is still intact. I was lucky enough to get Max Merritt's last new one in the early '90s, but perhaps he or another Packard vendor has some NOS by now. Barring that, you might match yours with a carburetor choke spring at any long-established, serious auto supply house.
I inveigled John Kepich to produce the bimetallic manifold heat valve thermostatic spring's cover in stainless steel, since the factory's mild steel cover is often rusted away.
Kepich Exhaust, Mocksville, NC: (336) 492-5629 oldcarexhaust@gmail.com

Grease the damper valve both ends with graphite powder which you can work in with kerosene, etc. Adjust it according to the Packard Shop Manual and you'll be good "for the duration."

Then you know about the Alfetta and other GP straight eights of the era. Mercedes-Benz campaigned a straight eight as late as 1955 which was leading Le Mans 'til the awful crash that killed 80 spectators that year. Mercedes immediately withdrew leaving the race to Jaguar.

Have often wondered why M-B fielded a straight eight so late in the game, but have found no conclusive engineering discussion to date.

Keep us posted and please share pictures of the finished project. All best.

BTW, GP racer Count Trossi, who owned all manner of era straight eight super cars, road and track, was a Packard distributor in Italy in the '40s, enjoyed his '47 Super Clipper much as Ettore Bugatti preferred an earlier Packard Eight on business trips over his own skittish but beautifully wrought products.

What kind of race car? GP or dirt track recreation?

There's more to it than that. The number of main bearings itself lengthens the crank, and Packard eights, sturdy, well-engineered as they were, were never about high rpm but low-speed torque, smooth tractability.

Duesenberg's Model J/SJ 420-ci dohc straight eight had but five main bearings, but they were wide. Buick's ohv 320-ci straight eights, babbitt bearings aside, were runners, as was Hudson's flathead, splash-oiled 254-ci straight eight, 3 x 4 1/2, hp rated at a very high for the 1940s 4,200 rpm. Both these engines had five mains. The stock Hudson straight eight propelled English Railtons, a sporting car driven in hill climbs and other competition and by the London police as pursuit vehicles. In 1940, Augie Duesenberg was selling a marine version of the Hudson eight.

You might consider finding one of Packard's unsung, woefully underrated but excellent engines, a five-mained 288-ci eight from 1948-on.
The cars weren't much to look at in those years, Packard more interested in their more lucrative jet engine contracts, phoning in increasingly me-too product, no independent able to approach Big Three unit costs, parts buying leverage, or afford the now "necessary" annual model changes and TV advertising.

Packard's 288 has like most Packard eights of the '30s, '40s, a 3 1/2-inch bore, but a mere 3 3/4-inch stroke, same as the 1936-37 Cord's Lycoming V-8 which stood up well to supercharging with only three mains.

Packard's 288 was used in the lower lines 1948-54, and there are plenty of donor cars about otherwise not worth restoring. It's a rugged, husky, well built, trouble-free engine and buying and rebuilding one won't bankrupt you. It shares the same 2.75-inch main journal diameter as all the other Packard straight eights of the '30s and beyond, as well as the Duesenberg J/SJ and long-produced Jaguar XK dohc six.

Keep us posted on your race car. In the days of the Depression Indianapolis 500 stock block "junk formula," a Packard One-Twenty (3 1/4 x 4 1/4, five mains) straight eight did well in the 1937 race 'til its clutch gave out.

Randy's right. And literacy's on the decline. Some of us cringe when we read some of the posts here and hope the posters take a little more care in their repair/maintenance procedures.
Something to remember: Packard advertised not just in mainstream news and business magazines, but in Literary Digest and the New Yorker.

A shop and parts manuals are necessary for any old car ownership, as is a dictionary on your desk if you want to communicate.

Read not just East Grand's ad copy, by company communicae at any level.

"The car built by gentlemen for gentlemen," remember?

Yikes. You toss 13 gallons of bad gas on the ground? No wonder you don't give your address. Hope you don't live near us. Next time, take stuff like that to a recycling center.

"The car built by gentlemen for gentlemen," remember?

I and others have had good results from J.B. Donaldson, Phoenix, AZ. www.steeringwheelsusa.com Have gotten many compliments for their redo of the senior "T-wheel" in my '47 Super Clipper. Longtime Packardites and other vintage/Classic mavens approve of Donaldson's work.