Verifying 1971 GS 350/455

Can't find the thread but Duane was saying big blocks had 4 holes in frame behind license plate. My GS455 only has the 2 round ones and it has a T400 with the VIN on it so I'm sure it's a 455 car.
Any other possible indicators other than steering joint?

 

I don't know about the holes, but the Big Block 71 frames have a different part number/Letter code then the Small Block frames.
Duane

 

Here is my Flint built GS BB frame #.
Troy

 

I know mines a 72, but the BA code is what identifies it as a BB frame, Flint built.

 

This is a photo of my 1971 455 car frame, you should find some kind of numbers/letters like this if you look under the left rear 1/4 panel behind the tire, they should be on the outside of the frame rail. Good luck.

 

Here's mine

 

That is cool! Did you notice yours and mine came out of the exact same batch?
Troy

 

Cool!
So 1237139 is BB frame?

 

Yes, that is my understanding. Also, this is what I've found to be the SB frame.
http://www.v8buick.com/index.php?threads/number-on-1971-buick-gs-frame-rail.343446/#post-2909898
Troy

 

I know my car is a 455 car but nice to have more evidence than the T400 with VIN since it is a 1971.....

 

Can someone please tell me the build date on this frame? or what the 2 12 713 stands for. Picture from above post.

 

Build date 2/12/71
Duane

 

Thanks Duane. The reason I am asking is on my X it appears clearly to have a 455 frame part number. However the date code appears clearly as 12713 and wondered if that could be a correct date. Being 1/2/71 three months before the build date. My frame is very rusty and a couple numbers are hard to read.

 

1237139 is the part number for the frame, which would be a "BA" frame, and would make it a 71-72 455 frame for a 2-door coupe/sedan.

The "12713" number is the date code for the frame, which would be "1/2/71", and the number "3" is possibly the shift code, ie. 3rd shift.

What is the Build date on the ID plate on the firewall?
Duane

 

Duane, Do the convertible frames have a diffrent part number?

 

04D

 

"Duane, Do the convertible frames have a different part number?"

Yes

 

Dwayne,
I will check the date code on my frame, I think my car was also built in April.

Some of the other posters here have the 2/12/71 dated frame, Could they post the date code off their ID plates?
Duane

 

You say you have a part number 12713, I'd suggest you have the same batch date code 2 12 71 3, 2/12/71 3rd shift. Is there any chance there is a 2 in front of that 12713?

My car is an 02C
Troy

 

That is very possible. For the 1971 model year they made very few B.B. Buicks, so the date codes for the B B parts, and especially the Stage 1 specific parts, often have a larger gap then they did in the 1970 and earlier years.

I will check the date code on my frame when I can. I know mine is the correct frame as we found the vin number on it when it was apart.
Duane