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I am rebuilding a 385 cubic inch basket case engine. The connecting rods which came with the engine are attached to 320 cubic inch pistons. The casting number is d-14812 5a. Does any one know what is the difference between 320ci and 385 ci rods. Hollander Exchange says they will fit but are different. Thanks

Sorry, can't help with specific differences between the 320 and 385 rods but the rods, regardless of which engine they were for, had many changes over the lifespan of the two engines, for example the change in the oil bleed hole from the leading side to the trailing side (valve side) which occurred beginning with the 9th Series, thinner babbitt beginning with the 10th series, finned rod caps beginning in the 11th Series, and the changeover from poured to insert bearings beginning with the 12th Series. I hope this is at least in-part helpful and that others will have more specific information. If you have a 12th Series or newer I guess you already know that finding correct flanged rod bearings will be a major challenge. If you're in the Babbitt bearing era, none better than Paul's Rod & Bearing for pouring and sizing.

I have a set of 1934 320 rods sitting on the workbench, we could compare some measurements and weights between them and yours if you wish. My rods of course are for poured bearings. Forging (not casting!) numbers on these are 216215. I guess you are aware that up thru 1936 the 320 used a different rod for the odd and even numbered cylinders while the 385 engine used a single number.

What year is the 385 you're working on, or if unknown what is the engine #? Curious, are your rods babbitted, fitted for OEM-type flanged insert bearings, or perhaps converted from babbitt to a non-flanged insert with some sort of rework to control the side-play clearance?

My Hollander's seems to have different information than yours, the only interchange it gives for the 385 is for 7th/8th series 385 rods in a 9th series 385 and says "for emergency use".

My 320 ci rods have flanged inserts. It would be nice to compare 385 ci rods with 320 ci rods. The rods must be slightly different if thy can only be used for emergency use. I have found Hollander to not always be 100% correct. Does anyone have both 320 rods and 385 rods to compare? Thanks

G'day Dean,
to PackardInfo bur sorry can't help with your request.

However I invite you to include the Packard, for which the the basket case 385 being rebuilt is intended to power, in the Packard Owner's Registry.

I just got an email from a friend who was watching the thread but no longer contributes. He advises that the crank rod journals on the 385 are longer and hence the rod is beefier and wider at the big end to accept a wider bearing, thus more bearing surface area.

Hi Dean:

I only have information through 1934 and they show only six digit numbers for eight cylinder rods. And the Hollander book is dead wrong. The 385cid rods weigh up to 3/4 of a pound more than 320cid rods.

I don't know what year car you are working on, but there are at least six rods from 1929 through 1934.

The information I have from Packard is fun to read because they call all 320 motors "standard eights". The number shown above - 216215 is not listed as well - and Packard says it should be either 216216 or 216217.

The numbers on rods of motors I have worked on match what Packard said they should be, so I am skeptical as to whether the rods you have are Packard.

As well, the 385cid motors use the same part number for all cylinders, but the numbers change each year.

Hope this helps a little.

My rod bolts to the crank with no play and is identical to another known standard 8 rod and piston I have access to. Sorry I should have used forging number rather than casting number. If the 385 rod is heaver it must be larger in some way. Maybe someone will have a 385 rod out of an engine to conferm some dimensions to compare the 2 rods. Thanks

If the 385 rod is heaver it must be larger in some way

I thought we had already answered that in post #5. I've asked that person who has both 320 and 385 rods to measure the big end widths and give us some weights.

I don't see we answered that yet. My 385 crank and the 320 crank I have access to, have the same size crank journals width and diameter. The 385 crank is much longer but not in the connecting rod journals.

OK, glad you made that known, apparently I was misinformed. We'll see if he comes forward with some weights and measurements.