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Hello everyone,
I have a 427 short block assembly that I need some help identifying. Casting number 3935439. I believe the date code is L23-8. I found that on the passenger side of the block. I believe it has L88 internal components. I was told that 40 years ago when I acquired the short block. It does have 4 bolt mains but the deck was machined so no stamped numbers. The engine was in storage for more than 30 years but turns freely with no scoring in cylinders. Is there something to help identify the crank or camshaft?
Thanks
Tom
Look at the crank. It's either Forged steel or cast-iron. Most likely forged-steel. And you are looking for 7/16 in bolts on the connecting rods. And then you need the numbers off the Pistons. You can get out a degree wheel and the dial indicator and check the camshaft in place.
Look at the crank. It's either Forged steel or cast-iron. Most likely forged-steel. And you are looking for 7/16 in bolts on the connecting rods. And then you need the numbers off the Pistons. You can get out a degree wheel and the dial indicator and check the camshaft in place.
Thanks. Are the part numbers for the pistons stamped or cast in. I do not see anything on the top of the piston?
ok. pic of top of pistons please. pull the oil pan and start snooping. I don't know if you want to unbolt ny rods or mains, but OEM bearings have a month-year stamped in them. sounds like a rebuild though. but it will tell you if journals are standard, .010 or what...
I
I know it was rebuilt when I acquired it. I has one cylinder sleeved. The oil pan is off. It looks like it has the 7/16 rod bolts. I need to get it on a rotating stand to check the bottom end.
The reason I am trying to figure out what I have here is that if someone could use this short block to use in a date coded car I may sell it. I want to be able to drive the car with pump gas and need to replace the pistons to do so. I have a set of 3919840 heads that were on it which had date codes of L 4 8 and I 30 8. I do not if it is wise to remove the pistons if I have a replacement L88 short block.
If this is real, save it. A 454 truck block from 73 to 90 is identical but for date codes and casting numbers. And actually for a pump gas driver? 96-2000 roller cam oval port flat piston 100 cc chambered L29 are out there for 500 bucks everywhere. But you need an electric fuel pump.
Over the oil filter pad there are tapped holes into the oil galley for oil cooler and pressure gauge pickup. The factory used blocks with 2 large pipe plugs for the L88 applications. Other blocks had one large hole and one that is 1/8 NPT.
Over the oil filter pad there are tapped holes into the oil galley for oil cooler and pressure gauge pickup. The factory used blocks with 2 large pipe plugs for the L88 applications. Other blocks had one large hole and one that is 1/8 NPT.
Whatever you think.
I must have the ONLY 4 bolt main block with 3 holes-- one for the oil pressure and 2 for the cooler. The truck block I'm running now only has 2 one 1/2 NPT and one 1/8 NPT. And they are both 4 bolt blocks
Over the oil filter pad there are tapped holes into the oil galley for oil cooler and pressure gauge pickup. The factory used blocks with 2 large pipe plugs for the L88 applications. Other blocks had one large hole and one that is 1/8 NPT.
GM did not have a "special block" for the L88 application, a block is a block. Example, the 1967 427 L71 (435hp) and L88 (430hp) used the same 4-bolt main bare block configuration.
GM did not have a "special block" for the L88 application, a block is a block. Example, the 1967 427 L71 (435hp) and L88 (430hp) used the same 4-bolt main bare block configuration.
to go a step further when cast all 427 blocks are the same. It’s finale machining that differentiates it’s usage.
also, a 2 bolt main may have been drilled and tapped to become a 4 bolt main by a previous rebuilder. or a 3/8th oil pipe fitting may have been drilled and tapped to a 1/2 inch pipe fitting sometime in the block's life..
throw out the book on what a 50 year old block may have come from the factory and what parts may still be in it.. the original cam will have 1/3 of its lobes worn off, the pistons will need to be replaced anyway, valve springs and guides and seals and seats will be shot anyway.
09-16-2018, 12:00 AM
427 short block identification
