'72 hp

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Feb 22, 2026 | 02:01 PM

#21

Rebelyell

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Quote:

Originally Posted by Piersonpie

Same thing, but right out the manual

Proof-reading skills not optimal as I age.
I don't spot a reference to either L48 or ZQ3 or RPO in conjunction with Base aka Standard engine in the above manual's page published September 1973.
Can you please point that out or circle it ?

Feb 22, 2026 | 02:07 PM

#22

Piersonpie

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From: Minnesota

No RPO codes, just showing the list of possible engines for 1974. I think we all know the 195 horse is the L48.

Feb 22, 2026 | 03:30 PM

#23

Rebelyell

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Quote:

Originally Posted by Piersonpie

No RPO codes, just showing the list of possible engines for 1974. I think we all know the 195 horse is the L48.

No, there are many who do Not KNOW what the correct RPO is. Plenty of guesses and assumptions; some right, others not.

Feb 22, 2026 | 03:35 PM

#24

leigh1322

Old Pro Solo Guy

Joined: Dec 2017

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From: Marlton NJ

I judge an L48 by its camshaft.
Every 300 gross HP 350, or ~270 gross HP due to compression, from 67 to ~ 79 used the same camshaft.
The 67-70s had 10:1 CR flattop pistons.
The others had dished pistons with ~8:1 CR
A few minor variations, a few had steel cranks, a few had 4 bolt blocks, a few had EGR intakes, none of that matters a bit.
Same basic engine.
A ZQ3 is the same as an L48. Nothing special about an ZQ3 code.
Been hearing that one for years.

Last edited by leigh1322; Feb 22, 2026 at 06:18 PM.

Feb 22, 2026 | 04:52 PM

#25

jb78L-82

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Joined: Oct 2007

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From: RI, Now Franklin/Nashville TN

Quote:

STANDARD ENGINE Standard EightCylinder Engine Ordering Code L48 Turbo-Fire 350-4/DE 8-Cylinder 350-cи-1n displacement

Did you not see my post "16 above???? That quote, AGAIN, is from gmheritagecenter.com, the official data source for the GM OEM owner manuals for GM cars and other documents for GM cars. The quote above is directly from that GM source for a 1974 corvette and is directly in line with my excellent memory that the 1974 Corvettes with a SBC 350 engine were either the L-48 base engine or the Hi performance L-82. You can clearly see the base engine is referenced as the L-48 in 1974. Go their website for yourself and look up the official documents for any year corvette and you can stop debating this question. Hope that helps!

Feb 22, 2026 | 05:32 PM

#26

Rebelyell

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Quote:

Originally Posted by kansas123

Someone asked a question about a de-smogged L-48, and it made me wonder if de-smogging it raises the HP and how much. Just curious. ('72)

If yours is a '72, repeat '72, and it's either an L48 or ZQ3, it has relatively low compression ratio. Whatever de-smogging is, unless you either Change piston crown Or combustion chamber volume, it cannot raise compression ratio nor increase power significantly. If it runs fine on 87 now, it should continue to do so; unless and until you make a major change of hard engine parts (while effectively & significantly raising static compression ratio).

Again, ALL of em (C3) had compression ratio significantly reduced beginning MY1971