1967 L88 - Corvette News (v10-3)

[Jack M.]

For those that may be interested, I scanned a 1967 Corvette News article regarding the L88:
1967 L88 - Corvette News (v10-3).pdf

[Harry S.]

Jack, very nice. Thank you!

[Paul H.]

Thanks Jack. I've never seen that. Interesting to see any kind of advertisement for a car they discouraged you from buying.

[Tom D.]

Anyone have the GM BOM (Bill of Materials) for the L88 option, 1967 version?

[Stephen L.]

Great article Jack!!! Enjoyed reading it.

[Tim G.]

Thank you, Jack.

[Mark F.]

Thanks, Jack,

The article refers to "Impact Extruded" Pistons (which the web says basically translates to cold forging)

I have seen drop forging (impressive and noisy)...
these guys can go up to 3,300 TONS (that's 6.6 MILLION pounds )

The attached link is interesting and provides more background on impact extrusion...

https://thunderbird-metals.com/impact-extrusion/how-it-works.html

[Duke W.]

Second page, column near the bottom discusses... "for those states that require smog control devices...."

The fact of the matter is that the '67 L-88 was illegal to register for road use anywhere in the USA because it didn't have a PCV system that was required in California beginning in 1961 and the other 49 states beginning in 1963.

For '68 and '69 L-88s were equipped with PCV and AIR systems, so I assume they met 49-state tail pipe emission standards, but I'm not sure if they met California's tighter limits.

I've never understood why Chevrolet went through the somewhat lengthy and expensive release process to make the complete engine available for plant installation. They could have just made the L-88 unique parts available over the counter to "upgrade" a L-71/72 to L-88 spec, which would have satisfied FIA and SCCA "production" rules, and, of course, any competent racer would have disassembled the engine for inspection and "blueprinting" and added a proper racing exhaust system and required safety equipment before hitting the track.

BTW, "impact extruded" is just a fancy way of saying "forged", and GM has used that term for its forged pistons going back to their first use in the '62 340/360 HP engines. It's done "hot", but at a much cooler temperature than steel. Both metals must be hot enough to be in a "plastic" state so they can be formed to the dies without the material cracking and separating, around 1500F for steel and 900F for aluminum.

[Jack M.]

Anyone have the GM BOM (Bill of Materials) for the L88 option, 1967 version?

That would be nice to see. Several years ago, I observed an Engineering Parts List being sold online, but it was far too expensive for me. I did save a few images... this was the 1967 engine info:
Engineering Parts List (1967 L88 & L89).jpg

[Jack M.]

Regarding the L88 emissions issue, I believe I posted the dealer launch info in the past. Herez an excerpt:
1967 Corvette - L88 Dealer Letter.jpg

[Duke W.]

It neglected to include the fact that it was not legal to register in all 50 states due to the lack of a PCV system. I'm surprised Chevrolet did not mention that. GM could have been liable for substantial fines if the EPA found out. Of course, with only 20 built it flew under the radar. I don't know if any '67 L-88 were ever registered for road use in any states any states.

Duke

[Michael J.]

Thanks Jack, very interesting. What carb did the '67 L88s have? And did they have a choke?

[Mark F.]

Hi Duke,

FYI - EPA was not created until December of 1970...

I don't know (or recall) what legislation would have ruled

[Tom D.]

That would be nice to see. Several years ago, I observed an Engineering Parts List being sold online, but it was far too expensive for me. I did save a few images... this was the 1967 engine info:
Engineering Parts List (1967 L88 & L89).jpg

Mr. M. Did you happen to copy a page with the PN of the center top rad support? Photos I have seen show what looks like 3874765 (second design for the '65 327s) or an almost identical part which the repro vendors are selling as a copy of 3873748, In 1981 this 65-67 TOP FAN SHROUD BRACKET - was for "396 and 427 L88”.

Both look alike parts have a tab sticking rearward for the fan shroud. L88s didn't have such a shroud.

Forum search for the ...765 number yields only one interesting discussion. "Was it ever used as the OE part for 1965 327s?" Possibly not... Going to write this up soon. /td

[Jack M.]

Sorry, Tom... I don't have any info on that item.

Mike- In regards to the L88 choke, I have a copy of the 3-page instructions listed in the AIM:
Miscellaneous Shipping List - 1967.jpg

L88 Choke.jpg