switchover to the LS6

[JRSully]

Most of you folks can probably answer this quickly. When did Chevy stop installing/offering the L78 and switch to the LS6 in 1970.??I suppose an early Feb 70 Cast date 854 block with CKO stamped on it would either have to be a Nova or Camaro.?? (found a bare block with no VIN) Thanks

[55chevy]

I thought they still had both engines available at the same time for 1970. [img]/ubbthreads/images/graemlins/dunno.gif[/img]

[Mr70]

It looks like there was an Overlap for the 1970 Chevelle,for both of those engines.
But for that date,I would think it would have to be a Nova or Camaro.The Chevelle didn't get it past Nov.-EARLY December 69 as of right now.
CKO code was shared by all 3 cars w/L78 w/man.trans for 1970.
Did you check by the oil filter pad for a VIN# stamping?
What is the Tonawanda build date before the CKO code?
If no VIN#,then possibly one of the 401 service engines?
Rick

Jim,

As far as the Chevelle is concerned, the switchover appears to have been around the first week in December 1969. The Baltimore plant appears to have been the last plant producing L78's based on buildsheet data collected. The sheets that have been collected are all customer ordered cars, and it appears that the plant was anticipating the stoppage of the option. There are 2 sheets that indicate "L78" in the RPO coded section, but also include both the "SS396," and "SS454" codes as well. These sheets are from 12-4. There is another sheet dated 12-8 that shows only the "SS396" RPO so it is quite possible that the plant had a better idea of LS6 production startup dates. It also appears that the Baltimore plant was the last plant producing L78's as all of the later cars (after mid. Nov. '69) appear to have been built there. I speculate that it might have something to do with wanting to use up as many L78 engines as possible, and the plants close proximity to Tonawanda. There are a few memos (from the fall of '69) that show the L78 option was being canceled in favor of the LS6. The timeline seems to support the dates involved, as far as when the option was actually canceled and production ceased.

[Musclecarkid]

Apparently it is not uncommon to find blocks unstamped with the VIN numbers around this time. The 12/08 Balt built 70 L78 did not have a VIN stamped on the pad or above the filter. Lately there has been quite a few LS6 blocks on ebay that also seem to have missing VIN stamps. Looks like the factory wanted to save a little time and skipped the VIN stamp process at a few assembly plants. What is your explanation on this?

[elcamino]

I know its a common belief that the VIN derivative stamp was omitted on some engines BUT this was an important item that the factory was responsible for doing. It was federally mandated by law. The VIN derivative was stamped on the engines prior to be installed in the cars and while it was being dressed out with carb, started, wires etc. If you cannot find the VIN on the engine, you need to assume the original block was replaced or it had machine shop work done to it. As was many hi-perf engines, owners were never satisfied and wanted more from them. Very few owners of these cars just used them for work, they abused them and many visited the dealer for warranty repairs etc.

I owned a new 1970 Chevelle SS 454 LS5 (136370K192352 date shipped. 4/19/70) and it was riddled with problems, used a lot of oil, crab problems, trany problems, front suspension problems and bad paint. I traded it off in 1972 for that reason as well as the poor gas mileage and high insurance rates.

[Mr. T]

Do you know if your LS5 still exsists, and hasn't been wrecked or destroyed? Ever try to track down it's where-a-bouts and buy it back?

[elcamino]

Someone a while back in law enforcement did a nationwide search for the VIN and said they got no hits. I traded in Michigan in 1972, it sat on the dealer lot for over a year and then they told me they never did sell it. I live near the selling dealer and checked for any records about 10 yrs ago but all the had was a file card with the VIN and my name etc and who bought the car. The owner of dealership (who was salesman in 1970) said the name of the buyer was some Wisconsin wholesaler they used to dump cars with that they could not sell.

[Musclecarkid]

Mike....Although you are correct stating the VIN's were supposed to be stamped on all engines by federal law, many were not. Human beings were responsible for this operation and occasionally missed this important step on the assembly line. I've personally seen quite a few blocks with the Tonawanda stamping on the pad and no Vin in either location. The 12/08/69 built 70 L78 car was verified by the original owner as never having it's original block replaced, yet had NO VIN anywhere on the block. I personally restored this 55,000 original mile car in 1998 and can tell you it was definitely a numbers matching car that had never been restored or altered. All castings were Sept 69. The car is available for anyone to inspect if your interested. In addition to this, Mark Meekins (mrz16) recently advertised a LS6 512 block on ebay that had NO vin, even though the Tonawanda numbers were present. "70 SS 454 LS6 CRR Engine" T0522CRR. (Ebay item# 2446538909) This is not the first I've seen.......Kevin

[Musclecarkid]

Greg.....With regards to your speculation,"the factory wanted to use up as many L78's as possible." Wouldn't it be safe to say, they only received as many L78 motors as needed to complete orders at a given assembly plant? (Maybe a few extras for replacements if a problem occured on the assembly line). Since the L78 was still available in 70 Camaros and Novas, I believe the extra engines would have been shipped to the respective Camaro and Nova assembly plants as needed. My assumption is when all customer ordered 70 L78 Chevelles were completed, the option was substituted with the LS6 engine. Even though the L78 Chevelle was to be canceled on Oct 30, 1969, there are a few we all know to have been built throughout Nov and early Dec.....Kevin