Need help with identifying motor 71 GTO
 

I've been researching how to identify my motor but I'm confused. Anyway I purchased a car sold as matching numbers. I'm not a huge has to be numbers matching kind of guy but if I'm going to say it's a numbers matching I want to know 100%
Now my trouble, I've been looking at a few websites I know what the code should be but can't find it. Hoping with the numbers I could find one of you
Smart guys can help me out. I have a 1971 GTO automatic. 455 with AC (so I was told)

I'll attach pics I have.
First numbers are front passenger side by the water pump they read
421965
Xv
These are very faint and hard to read.

The numbers at distributor read :
B237 and 86133

I also found numbers: B237 on the middle heads right below the valve cover.

Best source I've found; http://www.wallaceracing.com/enginesearch4.htm or http://www.pontiacpower.net/castnum01.html

You may have a Feb/23 1967 400
I could be wrong? Post in the street section for more help.

Have you gotten a PHS packet yet so you can look at the original window sticker and see what engine your GTO is supposed to have?
A 400 Automatic should have a YS code on the block and casting number 96 on the center exhaust ports of the heads. The standard 455 auto had YC and 66 casting heads. There was a 4-bolt 455 HO round port but doubt your car had that unless it is a Judge.

I have two correct 71 GTO YS 400 engines and a freshly rebuilt set of casting #66 71 455 heads. I am not trying to sell them but could be persuaded if yours doesn't have the right engine or heads and you want to put it back correct. If you don't have the original engine you can put a "correct" engine in-but of course even then you can never have a "matching numbers" car because everything will match but the VIN stamp.

(Well, never say never-some people mill the surface of the block and restamp a VIN to make theirs matching numbers)

I'll be calling in for the PHS as soon
As they are back. They got a message on there answering machine they are gone till Aug 8th for Barret Jackson. So I'll be ordering it up soon and let ya know soon as I do. I'm now positive it's not the correct motor. All codes and dates point to a 1967 400 with 061 heads built feb 23-1967.

It has a 8.2 inch 10 bolt for a rear with numbers that line up correct to the car so a guess is it's a 400 car. That's going on a hunch tho. Can't wait to get the PHS docs.

I got my PHS and looks to be a pretty standard GTO with a 400. Ill upload the docs I got from PHS and let me know what you guys think.

I have a 71 lemans sport that came with a 400 codes YS motor and a 4 BBL carb. Is this a "high performance" motor? I am try to figure out weather it should have the short or long body fuel pump.....Thanks

Deep canister '71, 72, -? pump is correct.

Not high performance, but stock was listed as 250 hp with the 4 bbl.