k_dean

Anyone an expert on old corvette big blocks? I've heard most of the original 427s had an oiling problem and had to be replaced. Does anyone know if this is true? If so, do you know any details regarding the replacement?

I ask because I recently purchased a '68 427 (not numbers matching) and was hoping I could find some information on what the replacement procedure was at a Chevy/gm dealer. Crossing my fingers that my big block isn't just one pulled out of a truck or something later on in its life. (Though hey, even if that's the case, she's still going to be fun) Any insight you guys or gals could provide would be appreciated.

Thanks in advance

AirBusPilot

You'll have to crawl around and get the casting numbers and any serial numbers off the underside of the block.

k_dean

I have them written down at home and can post them tomorrow. Though the engine is out and at the machine shop already.

AirBusPilot

That'd be cool, you can also do a google search. Let us know what you got.

bashcraft

Where did you hear this?

The 396 was produced first in 1965 with the 427 coming out in 1966. If there were any problems, (which I've never heard of) it would've been sorted out with the 396, and certainly long before 1968.

AdamMeh

Not sure about the oiling problem, but I do know that my brother's '68 427 car went through valve springs. To the point where he adapted a old cigarette lighter tire pump to thread into the spark plug hole so he could change out the the broken spring in a parking lot, side of the highway etc.

This was a bone stock car that he owned during the early to late '70s.

bashcraft

Why didn't he just replace them all at once and be done with it?

AdamMeh

BBC's tend to suffer from valve train issues in general. They were all replaced and it continued to happen.

early shark

One problem that was somewhat prevalent with the 427 engines was with the valve spring damper and valve stem keepers (retainer). Broken spring dampers and dropped valves caused many 427 cylinder case changeouts. Chevrolet's remedy was to revise the valve spring design and valve stem retainers with 1970 LS6 design.

Alan 71

Hi es,
It's nice to read it referred to as the "cylinder case"!!!!
Regards,
Alan

Easy Mike

Sounds like a Corvette Myth.

Engines which failed under warranty were replaced through the dealerships usually with assemblies coded CE.

There is a pad on the block at the front of the passenger's head. An engine ID code should be stamped there.

joewill

what you have can be deciphered by the casting number of the block and heads and intake.
then you will need to look at the casting date of the block, heads and intake, then you will need to look at the stamped numbers on the front right passenger side stamping pad.

post all of these numbers and we can tell you what you have. sometimes the stamped numbers are on the side at or near the oil filter.

gbvette62

There was a slight difference in the oiling system of 65-66 big blocks, that was changed starting in 67.

My memory is a little foggy on what the difference was, but I know the distributor is different, and an oil passage at the rear of the 65-66 blocks, I think is different too. From what I remember, the distributor and oil passage, were changed starting in 67. Later distributors can be used in 65-66 blocks, without causing issues, but I'm not sure the 65-66 distributor can be used safely in 67 up blocks?

This was the only thing I've ever heard in reference to big block oiling systems, and either way, would not have a bearing on a big block originally installed in a 68 Corvette.

As was stated by Easy Mike, engines replaced under warranty, were normally replaced using a CE block, though GM didn't start using CE blocks until around April 69. The CE designation was created by GM, as a way of tracking warranty replacements, under the 5 year/50,000 miles warranty, introduced in 69. The chances of a 68 Corvette getting a CE block under 1968's 12/12,000 warranty, are somewhat slim.

CE blocks weren't limited to warranty use, as service replacement engines, sold through GM dealers, were also stamped CE.

Mike Ward

Keep in mind that BBC were not installed just in Corvettes- the same basic cylinder case was used pretty much across the GM line of cars and trucks.

Tims68

I believe the '66 427 required a groove in the rear journal of the cam for proper oiling. The '67 and up 427 did not. If you replace the cam in a '66 427 make sure the cam has this groove or have it machined into the new cam.

k_dean

Wow, thanks everyone for all the great info. My dad and I have determined that what I have is actually a 454 with a 427 crank. Cab122836 is stamped on the block. You guys have given me enough info to know that I'm not dealing with something GM did, which is fine, I'm still going to have a blast with it, just wanted to double check to make sure the engine wasn't something special.

Mike Ward

454 and 427s sometimes shared the same block casting numbers.