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Discussion Starter #1
Guys my 66 GTO is Tri-4Speed, GeeTee Tipped me off when he saw a picture of my engine, and said the valve covers and heads look like they where not from a 66???????? So checking the block numbers my build sheet is coded WV and my block is YS, do I have an impostor? A non- matching numbers engine, and if so how do I tell what year the engine is. The numbers on the block are 0123048 YS and upside down are 204111203?????

Dose anyone have a clue?????????
 

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YS A-body 1966 389ci 335hp Powerglide 1x4 carb. 9778789 GTO

YS A-body 72 400 250 Turbo 400 L-78 R 1x4 481988 2 GTO
YS A-body 71 400 300 Turbo 400 L-78 1x4 481988 2 GTO
YS A-body 65 389 335 Powerglide 1x4 9778789 2 GTO
YS A-body 66 389 335 Powerglide 1x4 9778789 2 GTO
YS A-body 68 400 350 Turbo 400 L-67 1x4 9790071 2 GTO
YS A-body 69 400 350 Turbo 400 L-67 1x4 9790071 2 GTO
YS A-body 70 400 350 Turbo 400 L-67 1x4 9799914 2 GTO
YS X-body 74 350 200 Turbo 350 L-76 K 1x4 488986 2 GTO low comp
YS A-body 67 400 335 Turbo 400 L-67 1x4 9786133 2 GTO Califorina
YS A-body 73 400 230 Turbo 400 L-78 T 1x4 481988 2
YS B-body 72 400 250 Turbo 400 L-78 T 1x4 481988 2
YS B-body 72 400 250 Turbo 400 L-78 T 1x4 481988 2
YS B-body 71 400 300 Turbo 400 L-78 1x4 481988 2
YS B-body 71 400 300 Turbo 400 L-78 1x4 481988 2
YS B-body 78 400 180 Turbo 350 L-78 Z 1x4 568557 2
YS F-body 72 400 250 Turbo 400 L-78 T 1x4 481988 2
YS F-body 73 400 230 Turbo 400 L-78 T 1x4 481988 2
YS F-body 71 400 300 Turbo 400 L-78 1x4 481988 2
YS F-body 75 400 185 Turbo 350 L-78 S 1x4 500557 2
YS F-body 76 400 185 Turbo 350 L-78 Z 1x4 500557 2
YS F-body 70 400 330 Turbo 400 L-67 1x4 9799914 2

It appears a YS motor was never a 3x2 but instead a 4bbl. But it is a hit for 1966. It was used from 65-78

What is the code on the heads and the stamp on the back of the block?
 

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Discussion Starter #3
Block # 9799914 and passenger head 1119 and driver side 1099 not sure if this is the right numbers
 

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YS A-body 70 400 350 Turbo 400 L-67 1x4 9799914 2 GTO
or
YS F-body 70 400 330 Turbo 400 L-67 1x4 9799914 2

Your current engine either came in a '70 GTO or a '70 Firebird/trans am which definitely didn't come with triples.

Pontiac heads have their casting codes cast on to the center exhaust ports.
The numbers you gave don't cross over.
If the heads and block are from the same car it should be 11,12,13,16,47, or 614
 

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valvecovers on an engine doesnt identify nuthin. dont get too upset if you have a mixmatched motor. i hope i dont get too much flack for posting this but, first of all we all know what the real definition of matching numbers means. period correct is more like it. you got a better chance of winning lotto then to find a numbers matching car. i understand for example a restorer could go through the trouble of finding a block with the correct engine code and date code coinciding with the date on the trim tag. what about the rest of the drivetrain? these cars were driven hard n fast. im so sick of looking at gtos on ebay for sale with "matching numbers". most of the time its bullcrap...rickm.
 

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Heads
yr ci hp valves CC car
13 1970 400 330, 350 2.11/1.77 72 AT Ram Air III

More than likely you have a 350hp Engine out of a '70 GTO. Look at it this way. It may not have been a triple engine but it's still a GTO engine. Like Rick said finding a numbers matching car is no easy task. If you like the car, keep it the way it is and have fun with it.

My engine and transmission is out of a '73 grandville so don't beat yourself up to bad.
 

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Block # 9799914 and passenger head 1119 and driver side 1099 not sure if this is the right numbers
Those look like head date codes. The first digit is probably an "I", Sept 11, '69. You can verify the date of the engine thru the date code by the distributor.... Ex. D150. 0 = '70.

204111203 - If that # was running along side the timing cover, it's the engine vin. However, the 4 would be a B, P, R, Z or 1 for the assembly plant.

2 - pontiac
0 - 1970
 

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And, take heart. If you're not a numbers-anal guy, a '70 Ram Air III 400 is actually a better performing motor than a 389.
 
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