73 corvette ls6?
Thread Starter
7th Gear
Joined: Apr 2011
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73 corvette ls6?
Need some help on this one, found this I'n a barn working for AT&T. Bought it because it was number matching big Block 4 speed car. The heads and intake were missing but everything else is there. It's been sitting since 78 last tagged and was purchased from an estate sale. What is wierd is the name plate says 390hp, 10.25.1, 500ft lbs. Sure you could say someone changed it but this car still has the am fm radio and the interior looks to be unrestored and clean. I pulled the engine and it's 4 bolt main, pink rods, steel crank and has factory gm pop up pistons. Block casting is for 73 454. Have tons of pics, would like some help on this one. This is the 14th vette I've owned and probaly would not of purchased it except for the fact it was big block car as I've liked the chrome bumpers better. Thanks Bob
Burning Brakes
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Race Director
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The 454/390 gross HP was in 1970 and called an LS5.
The LS6 was a one year only engine installed in '71s and was rated at 425 gross and 325 net HP.
The 1973 version was an LS4 and rated at 275 net HP.
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7th Gear
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Hot Rod magazine in its March 1986 issue selected the 1973-74 Corvette LS6 454 as one of the "10 most collectable muscle cars" in the company of the 1968-70 Chevelle, 1970 'Cuda, 1970 Challenger, 1966-67 Fairlane, 1968-70 AMX, 1970 Camaro Z28, 1968-70 GTO, 1968-69 Charger, and 1967-68 Mustang. The big-block Corvettes were the only muscle cars produced after 1970 worthy of the list.[26] Copied this off the web! This is the reason i am asking the question about the engine.
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Misprint. They meant LS4.
Not too good at predicting the future of collectible cars either. The '73-'74 big blocks are the least valuable/least collectible big block Corvettes ever made, and probably always will be.
Maybe they meant '71 LS6.
Not too good at predicting the future of collectible cars either. The '73-'74 big blocks are the least valuable/least collectible big block Corvettes ever made, and probably always will be.
Maybe they meant '71 LS6.
Thread Starter
7th Gear
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Have a Cousin I'n Canada that used to drive down and tow Vettes up the back roads to his house I'n the 70's. The last one he pulled up was a blue 69 mako shark, He must of picked up 15 just I'n okla alone. Name is Eddie owns a mushroom farm. Big guy! Had his own body shop to restore them. Yes i know Canada is a big place but he loves Vettes. Thought you might know him! Thanks Bob
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Hot Rod magazine in its March 1986 issue selected the 1973-74 Corvette LS6 454 as one of the "10 most collectable muscle cars" .......... The big-block Corvettes were the only muscle cars produced after 1970 worthy of the list.[26] Copied this off the web! This is the reason i am asking the question about the engine.
There was no LS6 after 71.
GM Corporate built policy prohibited building anything that would not run on No-Lead regular gas, after 1970. This would make it impossible for there to have been 10.25:1 engine in 73. It wasn't until more recently that they where able to run higher compression ratios, because of computers and higher grade fuels.
The 71 LS6 was rated at 425 hp/475 torque, and only 9.00:1 compression. The only 73 big block was the aforementioned LS4, that was rated at 275 hp/395 torque and had the lowest compression ratio of all 73 Corvette engines at 8.25:1.
You say you've owned several Corvettes, so I assume you know how to identify an engine the engine stamp pad. 73 454's will have one of the following engine suffix codes; "CWM" = LS4 4 speed, "CWR" = LS4 auto, "CWS" = LS4 auto (Calif. emissions) and "CWT" = LS4 4 speed (calif.). If the car started life as a 73 LS4 big block, the 5th digit of the VIN will be a "Z" ("J" is a base 350, and "T" is an L-82 350). The original block casting number was 3999289.
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7th Gear
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Checked numbers on block came up 73 4 bolt main, just the gm pistons being pop ups and the plate showing the 10.25.1 got me wondering. I checked the production run and know they didn't make any with anything close to what's I'n it. But thought I'd ask just I'n case. Thanks for the info!
6th Gear
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Need some help on this one, found this I'n a barn working for AT&T. Bought it because it was number matching big Block 4 speed car. The heads and intake were missing but everything else is there. It's been sitting since 78 last tagged and was purchased from an estate sale. What is wierd is the name plate says 390hp, 10.25.1, 500ft lbs. Sure you could say someone changed it but this car still has the am fm radio and the interior looks to be unrestored and clean. I pulled the engine and it's 4 bolt main, pink rods, steel crank and has factory gm pop up pistons. Block casting is for 73 454. Have tons of pics, would like some help on this one. This is the 14th vette I've owned and probaly would not of purchased it except for the fact it was big block car as I've liked the chrome bumpers better. Thanks Bob
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