Almost like having a original engine car with no paperwork.

Debating what to do on restoration
 

That's Very True Stefano. It's Not that simple tho, because for the average guy, installing an "LS Engine in it and driving the Heck" AND " it doesn't take much time to swap out an engine / trans"

Done Correctly, (as You know) is a minimum of $10,000 ALL in to the "Average Guy" / REAL money.

If it's a Documented LS-6 with REAL proof, I say build For The History sake and most value in the end.

Finish it like it was Born to the best of your finances (Like I did), and as Dan Vasic said, Buy a 6 cylinder or 307 car, and like You said beat it Like you stoled it!

ORIGINAL, PROVEN, DOCUMENTED Cars with REAL Paperwork are the Foundation of OUR Hobby let alone THIs SITE if you really look at it with an open mind! FWIW.

Bill

I'm a numbers guy here to working on 3 70 z28 camaros 2 non original motor cars. So I chose to put mine deserving back to original as possible. The 2 non original motor cars I found orphaned motors from production line z28s. Dates are later but used a correct engine. You are dealing with a real documented Ls6 chevelle muscle car. Keep it real and find a CRV for it and a CE M22 for it. Original drivetrain cars are running short. If the non original motor cars are overlooked to restore correctly there will not be many more fresh concours restored cars to look at. Keep it real as others have said.

Build a day 2 car

Brand new GM Performance Parts 502 re-painted Orange and disguised to look as much like an original LS6 as possible. Pullies, valve covers, aluminum pancake intake manifold, etc.

Tell you what, I’ll take it from you so u don’t have to worry! One of my favorite cars of all time, would love to have it!
Good luck figuring it out, as my buddy says “ high class problem”!

Real deal LS6
Who cares if the drive train is long gone and forget the Warranty block BS that is old news in the hobby.
Find Correct Date Code drive train from other cars and install, many of my clients do that anyways.
Yes won't draw as much as a "Born With" drive train but it will still draw good money if the build is of high quality and you properly match the date codes for the motor or trans, Rear end are easy to find "Born With" as there is no VIN
More then half the real LS6 cars had there motors blown anyways.
You'll just be another modified 1970 Chevelle if you go the other way.
A Real Build Sheet trumps everything else IMO

I'd drop a 632/5spd combo in it and have fun. I'd also ad AC.

I would not try and make a date code correct / re-stamp LS6. Chances are 3 owners from now it will get passed off as a "born with drivetrain" original car, and someone will be really upset if they get taken. Fraud is probably not your intent, but who knows what will happen when the car changes hands.

Build a nice 454 that looks like an LS6, but with oval port heads, hydraulic roller cam, etc. Why worry about date codes? It will never be 100% original, IMO.

Install a visually correct 454 and 4 speed and leave the pad blank. Install headers so you don't have to mess with a smog system and day 2 the car. If you show the car, put a copy of the paperwork in the windshield. I'd be the first to drool all over it and be green with envy over the fun you could have lighting up the tires with no worries about blowing an original engine.