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GTO numbers matching?

2K views 1 reply 2 participants last post by  Pinion head 
#1 ·
I have a 1967 GTO that was built Late Oct 66. Engine date code is mid Nov, heads are 670 but date code early Dec. VIN is not stamped on block since that didn't start till late 67 production according to several websites. Everything matches according to PHS as far as it being an HO with WS block 4-speed car. I didn't go with original colors since it was Montego cream/white painted roof/with gold interior (to me that was butt ugly). For judging purposes am I correct in assuming that this is original equipment? I've read somewhere, tho I can't locate it right now, that all date codes should be within 60 days of the build date. Any help would be greatly appreciated.
 
#2 · (Edited)
Welcome to the forum!

Have you ordered the PHS docs on your '67. On the photocopied bill tag, up top, there is a box noting Engine Unit Number. Out in the dealership shops, the common name for this stamped number next to the two letter block code was the assembly number.

On '67 bill tags, it will not list the complete number, but, I believe, the last 4 digits. a good friend and I were pondering this a few winters ago, going through PHS docs we had on '67's and comparing to matching original blocks.

Typically, the complete engine casting dates will predate what people believe is the build date of the car by several weeks, to what can be several months. That date span depends a lot on the following:
-how high volume an engine, really low volume engines at low production plants can set in the engine bank for quite a while.
-how close the assembly plant was to Pontiac MI (engine asm plant), the assembled engines were transported by rail.
-could there have been a UAW strike that interrupted installation of engines. this effected many '71 Pontiacs.
-delayed releases of car models. lExample, the '69 Judge release. Pontiac engine plant created a large mass of WS and YZ coded RAIII engines that were cast and asm in late Oct/ early Nov of '68, stockpiled, then in many cases, were not installed til Feb and even up into late March of '69.

Another thought, if your GTO was built at Pontiac home plant, there is a possibility that since Pontiac plant had a body bank, where the painted bodies were slotted, being an odd color combo, the body for some odd reason sat in the back of a row in the body bank. That could exactly be the deal, if your '67 was built at Pontiac plant and its possible you could see slightlt later cast block than the noted body tag build. Other assembly plants like Fremont did not have a body bank, so when the body's came out of Fisher Body, they went straight to the line to be built.

If you have the PHS docs and have identified the actual assembly date, I am however betting the engine is out of a later built GTO, and a prev owner has installed it/ pieced it together. have run across this quite a bit.

On Pontiac plant builds, have personally examined engine castings that were cast 5 days before the noted assembly date on the builsheet of a '70 Pontiac. I've heard of instances, (two '65's) where the engine date codes were later than the body builds on the cars by several weeks. Again these were a home Pontiac plant deal, and the body bank issue existed.

Congrats on the car. One of the first '67's I ever had was a Montego Cream/ Signet Gold painted top Post Coupe. Had the gold bucket seat interior, console, AC. It was a really sharp looking car.
 
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