jasperLT1

I know about the aluminum radiator, metal shroud, expansion tank, HD brakes, HD springs, M-22 tranny, things that might be signs of a ZR1/LT1... But I was wondering if anyone knows if I can verify through vin#? My LT1 has the steel shroud with aluminum radiator, expansion tank, and I think the J56HD front brake calipers. Still need to check code # on my Muncie 4sp and rear spring count. But my car has an aftermarket radio & antenana, PW's and leather with deluxe interior. So does anyone know how to double check build specs by vin#?

Revi

Nope, no ZR-1 or specific info in the VIN. Just year, coupe/conv., production sequence number.

Easy Mike

Do you have any original paperwork with your car? Order copy? Tank sticker? Invoice? Window sticker?

Mashman

Vin tells you nothing but build sequence number.

What is on the engine pad? That is what will tell you what you have.

Build records for US cars no longer exist, but if your car was exported to Canada, then it is possible to get a verifiable build sheet.

jasperLT1

I dont have any of original price sheets or doc's, except for Owners Manual and some misc. receipts. I thought of checking the tank sticker, but not sure where it is. Can you access it without lifting body off of chassis? I have owned the car for over 18 years, and have only put about 5000 fun miles on it.... has lots of spunk.
I am going to check my block, but if it doesnt have original block, I wouldnt know if it Is a ZR1 chassis and running gear. It does have the 6500 tack, the 370hp/350ci console tag, and has either 4;10 or 4:56 posi rear end, need to check tag on that to. has no a/c & HD alternator... I guess the only tale, tale is going to be the block vin's or tranny and diff. vin's....

jasperLT1

also the vin/build sequence # shows, it would of been one of the last of 150 off the assembly line, which probably makes it a June or July car.

Easy Mike

If it is still there, it is on the upper left side of the top of the fuel tank. Some owners report being able to see a little of the sticker by peering around the fuel fill collar.

Yep. You have to drop the fuel tank.

ZR1s used stock frames. Nothing to check as far as that goes. Everything else in the package was optional equipment.

Try an archives search. A while back, a member was attempting to put together a listing of the ZR-1s. You might be ble to find your VIN on that list.

jasperLT1

I tried finding that thread or anything about that ZR1 list, I am new to this sight and could find anything like that. Was it a list of the C3 corvette's or the new ones? I'm not sure wher to look for his list....

Thank you,
J

Alan 71

Hi J,
Try clicking on this link.

http://forums.corvetteforum.com/c3-g...971-zr-2s.html

Regards,
Alan

Rowdy Rat

Post a photo of the engine stamp pad and the transmission stamp... That would be a good start.

If the power windows were factory installed, I'd say your chances of it being a real ZR-1 are pretty slim.

Regards,

Stan Falenski

gdh

Drew Papsun on this forum has done a lot of research on Zr-1's. As others have said check the engine stamp, the letter that comes after CK will tell you about the block. I knew of 3 not too far from where I live, not sure if 1 was sold as we lost contact with one another about 8 yrs ago. Post up the engine stamp numbers and letters.

Easy Mike

On this forum, we speak C3.

gbvette62

If the car is a ZR-1, it should have the J56 2 pin front calipers. These are pretty easy to identify, as they have 2 cotter pins in them, one at each end of the pad, instead of the normal single pin on top. The J56 also used a proportioning valve below the master cylinder, that was not found on any other Corvettes, and reinforcement supports, on each front caliper.

The 2 pin calipers, often get replaced over the years, with standard ones, but the proportioning valve and caliper supports, usually survive.

Besides the J56 front brake parts, a ZR-1 should have a 7 leaf rear spring and a rear sway bar. The rear end in both the LT-1 and the ZR-1, should also have the big block stub axles. These can be identified by the bolts and cast iron caps, that secure the U-joint to the stub axle, in place of the straps used with standard rears.

Below is a picture of the J56 proportioning valve, and the front caliper supports. These particular parts are on a 67. The 1970 proportioning valve is the same, but the caliper supports on a 70, might be a little different. The added support is the bare cast piece, bolted to the bottom of the caliper. This particular car is missing the J56 2 pin calipers.





On the right front of the block, is a machined stamp pad. It should have 2 sets of numbers stamped in it. One set will be a VIN derivative, and should match the last 6 digits of your car's VIN. The other set is the engine code. If it is a ZR-1, the engine code should read something like V0715CKV. The "V" is the Flint engine plant, where all Corvette small blocks were assembled, the "0715" is the engines assembly date, which I guessed at July (07) 15th (15), based on your VIN. The final 3 letters "CTV", is the code for an LT-1/ZR-1. If it is "CTK" or "CTU", then it's a "regular" LT-1. If the code is anything else, then it's either the wrong engine, or the car was not originally equipped with an LT-1.

The 6,500 tach and the 350/370 data plate, weren't unique to the ZR-1, thay came with all LT-1's. A 4:56 was not offered in 1970. The standard rear for the LT-1 and close-ratio trans, was the 3:70 posi, with the 3:55 and 4:11 as options.

The rear will have numbers and letters, stamped on the pad on the bottom of the rear. There will be a "W", for Warren MI, where the rears were manufactured, a date code and a three letter code, to identify the gear set originally installed in the case. A 4:11 would be CAP, a 3:70 is "CAS" and a 3:55 is "CAN". It's just about impossible to find the code on the rear, without having the car on a lift.

AC was not available with any 1970 LT-1, ZR-1 or otherwise. All 70 LT-1's used the same alternator, part number 1111491, 61 amp.

If your VIN is one of the last 150, your VIN number should fall somewhere between 17166 and 17316. If so, your car was likely built on either July 30 or 31, 1970.

Rowdy Rat

The proportioning valve was phased out as part of the J-56 option in early 1968. From that point through 1972, no J-56 optioned cars use it. I can't speak for the 1973-1975 Z-07 cars.

No rear sway bar on any 1970-1972 ZR-1... The heavy duty stub axles were also standard on base engine automatic cars so that might not be the best indicator.

The 4.56 was not listed on the power team charts but was available with the 1970 ZR-1 option only. I believe that we know of 3 or 4 1970 ZR-1s with this axle ratio. Dan Pepper's car has one... Sal Carbone's old car had one... I know of at least one other off the top of my head.

The transistor ignition distributor was 1111491... The 61 amp alternator was 1100884.

Regards,

Stan

jasperLT1

Your guy's input has been great... I thank you very much. This is definately a great site for knowledge and help. I have been going out and digging into some of these suggestions, but it has been tough because I always put it away for the winter under cover in my shop beweetn 2 boats right now. Makes tough access to alot of this information. Plus it dont help i need new batteries in my flashlight, it has been teen tempertures when I get off work, and tires are frozen to ground, with about 12" on each side of the car for access....lol
The block stamp is really hard to read, but is looking like it might be a replacement block w/2.02 heads on it. Come spring or a lil warmer day, I will back out and see if I can find tank sticker, or under dash paperwork. Reguardless this has alwys been one of the best chevy's I ve ever owned (which has included SS's, 5 windows, and sport coupe chevelle. My parents also had a 1970 SS 454 LS7 Chevelle when I was a kid, and my mom got it in the divorce, and traded in on a Pinto station wagon for $500.00, because it needed a tune up....lol)
All in All, It is a CORVETTE.... and who doesn't like to take one of those for a spin... If it does turn out to be a ZR1, maybe that would just help my daughter's college fund a little better.
Thanks again, and I'll try to attach photos, as soon as I can figure out how on this post.
I did register it with www.1970corvetteregistry.org

dmaxx3500

cool car what are the last 6 numbers of your vin#?

joewill

power windows was not available as an option on a ZR1, the odds are overwhelming that you do not have a ZR1.

jasperLT1

It is 17173, so within the last 150 built, I have found out it was built on July 30th.
Wish GM would of had some kind of record of what was installed on there production order(vin#)....

The research I've done says that no ZR1's had PW, radios, or any of the bells and whistles...also...
But either some one might of added the PW after or added the M-22 tranny & j56 brakes... that is what has me stumped. I dont have the original manifolds, distributer, and carberator... so Im down to dropping the fuel tank and checking to see if the tank sticker is there...

Revi

FYI - If the tank sticker is still on the tank, DO NOT try to pull it out through the fuel filler/gas cap hole. You will most likely destroy it. Take the extra time and drop the tank to retrieve it.

1. It's doubtful that someone would add all the necessary parts/pieces needed for power windows.

For items 2-4 all you have to do is look under the car and take a picture. You shouldn't need to remove anything.

2. Does the rear spring have 7 or 9 leafs? 7 = possible ZR-1, 9 = no ZR-1.

3. Have you looked at the half shaft universals? If they have the block caps (circled in red) you may have a ZR-1. If you have the straps (circled in yellow) then no ZR-1.


4. Slide under the car and take a picture of the numbers stamped in the side of the transmission. Is it actually an M-22? Does the VIN derivative match the VIN on the A-pillar?

Eljay

Before you determine ZR-1 or not, have you gone through all the steps to be sure it is actually an LT-1?