I've got an old sbc block that I'm trying to identify. I've looked online and found some info but not for some of the markings. The block casting number is 3932388 which could be either a 1969 302, 290HP with 4 bolt mains or a 1969 350, 300 HP with 4 bolt mains. I only have the block with main caps so can't confirm which. The next issue is, the engine code and partial VIN pads are both unmarked. I assume a replacement block or filed pads but don't know for sure. I do have the casting clock ID'ed at 3PM but there are a few other castings I can't identify. One, close to the block casting number reads K16 8 with a round symbol between the 6 and the 8 with a vertical line cut into it. The next is on the opposite side of the block casting number and looks like T18 with CONVI or CONV1 below it. Any help would be greatly appreciated. I know this is newer than 1964 but the basic sbc architecture is the same from 1955 onward and maybe this is worth something to a restorer.
'68-'76, 350 cu in. passenger car, 2 bolt mains, is what the "How to rebuild the Small-Block Chevy" book states. However, I have the same motor in my '32 Roadster and my block has four bolt mains. I know where the motor came from, so nobody drilled the block for 4 bolt mains. Hopefully someone can clear it up.
This casting number ending in 388 is a 1969 only used number. And only for a short period. Since they built exponentially more 350 300 horse motors...and lesser hp rated truck motors that were still 4 bolt, i'd assume its one of those instead of a very low production 302 engine. No info on the front pad could have been because it was decked during a previous rebuild. There is no difference whatsoever between a 302 block and a 350 4 bolt block. Only difference is if there is an old assembly code showing a DZ suffix. Then it might be worth something to a restorer. It may still be worth more than a normal 350 4 bolt core for a Camaro or Corvette restoration.
I've got the same engine in my car. But i still have the suffix code. Mine shows as a 300hp 350 from either a Camaro or chevelle.
November 16 1968 casting date. 1969 model year. With the stamped numbers milled off, that's as good of an id as you'll get. Sent from my Trimline
The factory deck surface finish was broaching, leaving faint straight lines, front to back. Most machine shops use a rotary mill to resurface heads, so you'd see circular cuts if was refinished that way. Rubbing a wetstone (knife sharpening stone) over the surface will usually reveal the surface finish, so you can tell if it is original, or has been milled (or ground or filed off)
Jim and others...Camaros.org and other sites say this block was used from 11/68 to 4/69. That casting date should be an L on Lloyd's engine....but sure looks like an I to me..which would have been September. Earliest casting date I've seen on the net is October "J". Could be the tail of the "L" was chipped off somehow..the 386 was later superceded by the 618 for a few months...then on to the 010 block Chevy used forever.
Whether or not a a block has 2-bolt mains, or 4-bolt mains had nothing to do with the casting numbers. The number of bolts that hold the main bearing caps on was set when the block was machined, as it is a finishing process. GM diverted blocks all the time, for different destinations. I have seen examples of all manner of combinations that the books and internet sites claim do not exist.
According to this it is. https://nastyz28.com/sbchevy/sblock.html They also confirm that it is either a 302 or a 350 block. Big Journal 4 bolt main 4 inch bore block. If the block is good a guy can build what ever he wants out if it be a 302/327 or 350 or a stroker depending on what crank, rods and piston combination go in it. If you want high Bubba factor call it a 69 Z28 302 block no matter what guts it has in it.
"One, close to the block casting number reads K16 8 with a round symbol between the 6 and the 8 with a vertical line cut into it." Well the round symbol with a line cut into it is easy... it was a screw that held the number tag onto the pattern!
Mr48, BUT... If it does not have the DZ on the block stamped, it's worthless as a 302 I would think.? I see what you did there with the Bubba factor. lol. Lippy
BP " I " stands for Sept. which is not a "very early" block And lip is correct it is just a 4" bore 4 bolt block. Pat
1967 was the last year of the rear vent in the block, another thing to look for on sbc’s. Sent from my iPhone using The H.A.M.B. mobile app
Lippy You are partly correct, the musclecar/matching number crowd dictates the value on a "true" Z/28 302 engine (or bare block). Now, as a hotrod minded guy, I'd love to have a new GM service replacement (CE) 302 engine, at least a long block, the rest is sourced easily enough.
The Jalopy Journal
