I am in the process of buying a 74 BB Convertible from a friend of mine. It is a 17,000 original mile car with the original motor pulled at 16,000 miles and replaced with a crate motor. The original motor comes with the car. The car is a two owner car and the guy that I am buying it from tells me that he was told by the original owner and a dealer that the crate motor is a LS6. How do I tell for sure. I know from driving the car that it isn't the standard 275HP 454. This thing has some serious HP. From my experience with other high output motors, I would say that it is well over 400 RWHP. Any information would be appreciated.
Bob

 

post all the casting numbers, and whats on the stamp pad on the engine block

 

I will the next time I am at his house. I am buying the car on a payment plan and go out there once a month to make a payment. Thanks.

 

First thing I would do is pull the crate motor and sell it, then reinstall the LS4, then put the car on the show circuit. An original 74 conv big block is rare, but then add in only 17K miles and it is truely a rare bird.

What did you get it for? A car like that should sell for high $30's or more. Conv, last year for the big block, only 17K miles = Very nice Any pics?

 

I have a 74 coupe with the LS-4 and am considering pulling the motor out and setting it aside to preserve its value and dropping in a ZZ502 crate motor. Please post pics of yours!

 

The car is not perfect. The paint is in good shape except for the rear bumper which has been replaced with a fiberglass unit and hasn't been painted to match the car yet. The color is yellow with a white top and buckskin interior. The front bumper will probably have to be replaced soon. The car has been garaged all it's life and the original top and interior is absolutely mint except for a couple of small paint chips on the piece behind the passenger door and the rear compartment. I don't know the proper name for the piece. The original hood has been replaced with a Ecklers L88 Hood, but he has the original. The original motor is missing the exhaust manifolds. The present owner may have them, but can't remember for sure. Other than these items, it is in excellent condition. He put new side pipes on it last Christmas and they haven't even started to discolor yet. He offered the car to me 3 years ago for 14,500 and honored that price again this time and I took it. I don't have pictures yet, as the car is buried in his garage and he hasn't unpacked everything from his recent move to the country. I will get pictures in the next month or two.

 

Sounds like with correct bumpers, reinstall the original hood, paint, and correct exhaust, you will be ready to go. It is a rare car so be careful what you do with it.

tom...

 

Sounds like a great buy you got. Good luck and have fun with it. Sorry can't answer the question you asked though.

 

Yup - sounds like a great deal.

 

nice deal, especially if you get 2 engines (sounds like a very nice crate bigblock + original bigblock) and 2 hoods!

Tom73 and I disagree. First thing I would do is take the car in its current configuration to the dragstrip to see what that LS-6 can do!

 

The LS 6 motor may be worth more then the car!

 

Hmm, funny thing I was thinking the LS-6 was worth some serious ...cash .... maybe

 

I think LS6's were casting #3963512 this was a block casting # for a number of configurations of 427 and 454 blocks from 1969-1971. The block was only part of the story on an LS6, the rest included cam, heads, carburation, etc. etc. My block is LS6 stock but nothing else is left of the LS6 configuration. I'm guessing you have a very nice LS4. If the LS6 crate motor is all together it should be worth some cash, especially to a 69-71 Vette owner missing an original motor

 

First I would find out if is really a LS6 engine. Should be an aluminum intake with a 4 bore holley. If the car is air conditioned, probably forget the LS6.

 

The motor in the car does have an aluminum intake and a 4 bore holley. The car is air conditioned, but the compressor is on the stock LS4 that comes with the car. I am strickly going by what the guy that I am buying the car from is telling me, but he is knows his stuff pretty good. He has owned over 15 Corvettes over the years and all were very collectible models. He now is down to just one, a 63 S/W with 40K miles. Bought from the parent of a young man that went to Vietnam and didn't come back. Beautiful original car in prefect condition. I will get the numbers next time I am out to make a payment. He has been extremely kind in letting me pay the car out the way he has.
Bob

 

I was never a fan of 74 to 82 Vettes, but the existance of the LS6 and its HP would make the car. And also put the AC back on as that would complete the package. Hot car with a cool interior.