1980 Corvette needs an engine
Thread Starter
Racer
Joined: Feb 2007
Posts: 290
Likes: 0
From: Winchester CA
1980 Corvette needs an engine
Hello to everyone. So, it's been a very long time since I've worked on my 1980 Corvette. I would like to replace the tired 305 engine. I need help as to what my options are with long blocks. I'm interested in a 350. I live in California so I will be transferring all of the original accessories over to the replacement engine. She needs to pass the visual and sniffer tests. I understand that the 350 block is visually identical on the outside as the 305. I'm also aware that GM made two 350 engines and the 305 engine for the 1980 Corvette. Please correct me if I'm wrong on those engine options: 350 (L82, 230HP), 350 (L48, 190HP), and 305 (LG4, 180HP California only). What 350 engine long block would be ideal for my swap and would it pass the visual test and more importantly the sniffer test. I'm turning to my fellow Corvette enthusiasts for help with this. My budget is around $3,000 for a long block engine. I really want to ditch the 305. Thanks to everyone in advance. Pass the wave!
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
Call John at LJ's Speed and Machine in Napa, CA.
They just built the 496 for my 73 and they do amazing work.
John builds many Corvette engines for the local Corvette specialty shop and has been building hot rod and racing engines for over 50 years.
I know he has built several engines for guys that want to or need to stay smog compliant.in their cars.
Good luck.
They just built the 496 for my 73 and they do amazing work.
John builds many Corvette engines for the local Corvette specialty shop and has been building hot rod and racing engines for over 50 years.
I know he has built several engines for guys that want to or need to stay smog compliant.in their cars.
Good luck.
Burning Brakes
Joined: Jun 2020
Posts: 881
Likes: 113
I'm Not a Californian.
but if they do a visual, the block's casting number (at driver's rear) is a dead giveaway. 350 & 305 have quite different CNs.
also,block's front passenger side ID stamp pad for 305 should have ZCA suffix; that's unique to '80 305 cali vette.
heads have different CNs as well.
but if they do a visual, the block's casting number (at driver's rear) is a dead giveaway. 350 & 305 have quite different CNs.
also,block's front passenger side ID stamp pad for 305 should have ZCA suffix; that's unique to '80 305 cali vette.
heads have different CNs as well.
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Too bad you are in CA, a 421 SB would be an nice choice with plenty of power when needed. If you can get it to pass SMOG, you're golden.
Last edited by Buccaneer; Sep 1, 2020 at 12:03 AM.
Safety Car
Joined: Jul 2005
Posts: 3,694
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From: WI
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
Just the 305 block. you can put a 3.75 stroker crank in it with a .040 overbore for 336 ci total. With CARB approved good flowing heads should make a solid 400 hp with the right cam and headers. That combo would likely blow your budget though.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
I would stick the old Goodwrench 350 in this although they have went up pretty dramatically........I seriously doubt anyone at the smog check has ability/knowledge/time to be checking block casting numbers......
If so, what do you do if you grenade a unicorn 80' Cali Vette? 2 piece 305's are even more rare than 350's now because they all went straight to the scrapyard.
Please correct me if I am wrong on the smog check.......
The Goodwrench 350 is an exact duplicate of your 305 externally.....paint it blue and stab it in.
Jebby
If so, what do you do if you grenade a unicorn 80' Cali Vette? 2 piece 305's are even more rare than 350's now because they all went straight to the scrapyard.
Please correct me if I am wrong on the smog check.......
The Goodwrench 350 is an exact duplicate of your 305 externally.....paint it blue and stab it in.
Jebby
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Burning Brakes
Joined: Jun 2020
Posts: 881
Likes: 113
OP
? Perhaps Your cali SMOG regs Exempts/permits/waivers a "Year & Model Correct Exchange" such as an '80 L48 or '80 L82 swap; I surely don't KNOW.
Such as a "CARB exempted engine package" If so, rest assured there's "a process."
I do KNOW this; laws/regs everywhere are constantly changing. Including cali.
Before you buy anything
strongly suggest you obtain experienced advice from savvy rodders Near You; those who routinely deal w/ Your SMOG authority's regs & practices
Maybe a corvette club Near You with a large C3 contingent ?
Please don't speculate or rely on others who do.
? perhaps you direct your questions to a cali smog authority here
https://www.smogcheck.ca.gov/PubWebQuery/ARD/Search.aspx
https://www.bar.ca.gov/Industry/Engine_Change_Guidelines.aspx
And, while a stroker 305 is doable, it's a bad choice for so many reasons.
305 small bores severely restrict 2-valve heads' breathing. Lotta dough for nuttin' much.
? Perhaps Your cali SMOG regs Exempts/permits/waivers a "Year & Model Correct Exchange" such as an '80 L48 or '80 L82 swap; I surely don't KNOW.
Such as a "CARB exempted engine package" If so, rest assured there's "a process."
I do KNOW this; laws/regs everywhere are constantly changing. Including cali.
Before you buy anything
strongly suggest you obtain experienced advice from savvy rodders Near You; those who routinely deal w/ Your SMOG authority's regs & practices
Maybe a corvette club Near You with a large C3 contingent ?
Please don't speculate or rely on others who do.
? perhaps you direct your questions to a cali smog authority here
https://www.smogcheck.ca.gov/PubWebQuery/ARD/Search.aspx
https://www.bar.ca.gov/Industry/Engine_Change_Guidelines.aspx
And, while a stroker 305 is doable, it's a bad choice for so many reasons.
305 small bores severely restrict 2-valve heads' breathing. Lotta dough for nuttin' much.
Le Mans Master
Joined: Mar 2006
Posts: 5,775
Likes: 585
From: Texas
You can install any CARB-legal engine into the car provided it's the same year or newer. You could install an LS3 if you wanted, provided you also installed all the emissions equipment for the newer engine.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
I would stick the old Goodwrench 350 in this although they have went up pretty dramatically........I seriously doubt anyone at the smog check has ability/knowledge/time to be checking block casting numbers......
If so, what do you do if you grenade a unicorn 80' Cali Vette? 2 piece 305's are even more rare than 350's now because they all went straight to the scrapyard.
Please correct me if I am wrong on the smog check.......
The Goodwrench 350 is an exact duplicate of your 305 externally.....paint it blue and stab it in.
Jebby
If so, what do you do if you grenade a unicorn 80' Cali Vette? 2 piece 305's are even more rare than 350's now because they all went straight to the scrapyard.
Please correct me if I am wrong on the smog check.......
The Goodwrench 350 is an exact duplicate of your 305 externally.....paint it blue and stab it in.
Jebby
$1200 shipped from Summit. One and done.
You could not mess with it for that.
The original is on a stand outside under a tarp.
Even if $2000 now , its the way to go.
Melting Slicks
Joined: Jul 2004
Posts: 3,302
Likes: 8
From: Avon, Indiana
The testing center will know that it is a 1980 "California" car. They will check the timing to make sure that it is set at the factory spec. A different engine might not pass at that timing.
When I lived in California, I had a 1980 that was not a "California" car, and it had a 350 stroked to 383. With the timing at the factory setting, it would pass the smog but with the timing that retarded it got very hot. I would not do the swap without assurance from an experienced builder that it will pass.
When I lived in California, I had a 1980 that was not a "California" car, and it had a 350 stroked to 383. With the timing at the factory setting, it would pass the smog but with the timing that retarded it got very hot. I would not do the swap without assurance from an experienced builder that it will pass.
Drifting
Joined: Aug 2019
Posts: 1,510
Likes: 498
When Ohio had E Check program , on the vehicles that wouldn't pass the sniffer but would pass the visual we would run gas down to 1/8th tank then add a big bottle of rubbing alcohol from the local grocery store in the tank and go right back up there and pass with flying colors , the emmisions stickers were good for two years back then , cars like Mazda RX7's had trouble passing due to oil consumption and rubbing alcohol trick would get them passed then fill it back up with gas when we was done
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
I see you live in Winchester.
Riverside County does require smog inspections, however there are areas and counties around you and within California that are smog exempt and do not require smog inspections.
Do some research and see if you have a friend or relative who lives in one of the smog exempt areas or counties and register it there.
I lived in a smog exempt county, restored an 83 GMC 4X4 shortbed that I drove for years and never needed to smog it.
Have you thought of dropping in a nice LS replacement.
I believe you can, you would be smog compliant and would gain all kinds of HP.
Do some research.
Riverside County does require smog inspections, however there are areas and counties around you and within California that are smog exempt and do not require smog inspections.
Do some research and see if you have a friend or relative who lives in one of the smog exempt areas or counties and register it there.
I lived in a smog exempt county, restored an 83 GMC 4X4 shortbed that I drove for years and never needed to smog it.
Have you thought of dropping in a nice LS replacement.
I believe you can, you would be smog compliant and would gain all kinds of HP.
Do some research.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
What areas around Winchester are exempt?
GM is now selling their Vortec 350 crate again for 3800? Swap the cam for a ZZ4, good cat, get the car nice and warm bet you pass. IF you had a problem and saw the smog ref he would pass you....taht sticker inside your door is gold out here in Ca.
These stupid emissions #s keep getting tighter....Used to be one could drop a 400 or 383 in all day and pass...wanting to do that with a C4 but this time do a pretest and observe the actual and max numbers before doing it.
Gotten to the point where clean oil will help you...unfortunately they can tell if you dilute the fuel most times. Just repeating what the local smog operator told me.
Friend swapped a stock 6.0 in his 5.3 Silverado...no mods at all he failed the sniffer. Unreal.
Anyway OP I bet if you go that route you will be just fine. A fresh 350 ought to burn cleaner than an old worn 305.
GM is now selling their Vortec 350 crate again for 3800? Swap the cam for a ZZ4, good cat, get the car nice and warm bet you pass. IF you had a problem and saw the smog ref he would pass you....taht sticker inside your door is gold out here in Ca.
These stupid emissions #s keep getting tighter....Used to be one could drop a 400 or 383 in all day and pass...wanting to do that with a C4 but this time do a pretest and observe the actual and max numbers before doing it.
Gotten to the point where clean oil will help you...unfortunately they can tell if you dilute the fuel most times. Just repeating what the local smog operator told me.
Friend swapped a stock 6.0 in his 5.3 Silverado...no mods at all he failed the sniffer. Unreal.
Anyway OP I bet if you go that route you will be just fine. A fresh 350 ought to burn cleaner than an old worn 305.
