The Stovebolt Site Forums The Parking Lot Big Bolts 1948, 6400 correct engine

what would be the original/correct engine for a 1948, 6400 truck ?
i,v been told that the one that is in it now is a 250 am i right in thinking that it is a much later engine,
also it has a 4speed manual trans,, will this most likely have a ,grannie, low
thanks mike,,

5000 & 6000 series truck engines in 1948 were 235s (USA trucks).

The standard transmission in that size truck was a SM420 4-speed. It has a very low reverse and first speed gear and 1:1 4th speed gear.

thanks tim,
so is the 250 a later engine ,, and is it better than a 235
i,m going to have to make the best of what i,ve got or can get as old chevy,s are still quite rare in the uk..

Information on Chevrolet straight six engines.

I'm partial to the stovebolt engines, but it seems to me that 250 would be a fine engine. It has 7 main bearings and is a stroked 230, which my father-in-law had in a mid-60s truck. That was a strong, reliable engine.

as far as i know it is an SM420 transmission,
the question i now have is what PTO was available to fit these trans,,

Several were available and it depends entirely on what you wish to do with it, i.e., what are you wanting to power with it?

There were single gear single speed, one forward & one reverse, different ratios, two speed, etc. All made for different applications
so it is important that the correct one is selected. Then the problem will be one of locating one in working condition as they are no longer made for the old 420 transmission.

looking/planing to fit a hydraulic pump then make a dump tilt bed to use for vintage transport and the like , as i have a couple of vintage tractors and a 1936 austin ten hotrod pickup ,

Welcome,Spanners! My friend has two P.T.O.'s available,since he turned his flatbed/dump project,into a 4X4. The SM 420,in his application,came out of a ,(I believe),'69 C-65. It has P.T.O. mounting plates,on BOTH sides of his trans. Nice set-up,in case you wanted to "run" a pump for the hoist,and another P.T.O.,for a winch. his,(as I remember),are 4-bolt mount. If interested, send me a P.M., and I can take pic's,and find out what he's asking. They're both single-speed.

Also the 250 is not a "Babbit Pounder", it has insert bearing rather than poured babbit and is oil pressure fed crankshaft, not dip/splash lubrication for the crank-shaft.

The SM420 was available from 1947-1967.

All 216/235/261 engines had internal lubrication to the crankshaft main bearings.

The 216 engines and early 235 engines had babbetted rod bearings that were lubricated by directed oil spray and dippers (splash-oil was a lubrication description for earlier engines).

The later 235 and 261 engines' insert rod bearings were internally lubricated.

The 250 engine's 7 main bearings was a significant difference between that engine and the later Stovebolt 6 engines (all 216/235/261 engines had 5 main bearings).

Not a Sm 420 if it has PTO covers on both sides, sound like later '68 - up 465 unit.

If you are absolutely right about this I feel much better about my VIN# not matching anything.
My '48 6?00, 2 1/2 ton, door plate is worn away with only stamped #'s that jive with vehicle and known history, but do not correspond with the transferable registration. It has a 1948 216, so I was thinking original motor but those #'s don't match either.
Should I be worried? I bought this truck in Feb.
I've read a lot on this forum about VIN's and was getting very nervous.
I want to make it a working truck, so I've been waiting to transfer till it was close to road worthy.
Any comments that I could rest assured would be appreciated.

Thanks,
D.

D,

Your title may have the engine serial number used to identify it not the chassis number. Have you checked to see it that's the case? Most States did it this way until the mid 50's.

If your engine has been replaced you now have a truck where none of the numbers match. If it were me I'd call my DMV sooner than later to get it straightened out. They may require a statement from the previous owner and if you wait it might be hard to make that happen.

Mike B