Swapped...un-swap - Pontiac GTO Forum
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post #1 of 19 (permalink) Old 03-27-2019, 11:08 AM Thread Starter
 
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Swapped...un-swap

Few months ago I bought a VIN242 GTO.It had a stock 350 verified by PHS.I replaced it with a 400 that coincidentally had block and head #'s
were within a month of the assembly date of the car.For value,should I have kept the #'s matching
350?Checked various 68 GTO spec sites and never found specs or info for this engine..thanx
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post #2 of 19 (permalink) Old 03-27-2019, 12:16 PM
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No 1968 GTO came with a 350 cubic inch engine. It came with a stock 350 HORSEPOWER 400 cubic inch engine. The first GTO to get a 350 engine was the 1974 GTO, followed by the 2004 model year. The only factory installed displacement engine for the GTO for 1967, 1968, and 1969 was 400 cubic inches. Period.
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post #3 of 19 (permalink) Old 03-27-2019, 06:31 PM
 
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No 1968 GTO came with a 350 cubic inch engine. It came with a stock 350 HORSEPOWER 400 cubic inch engine. The first GTO to get a 350 engine was the 1974 GTO, followed by the 2004 model year. The only factory installed displacement engine for the GTO for 1967, 1968, and 1969 was 400 cubic inches. Period.
X2 on that one. No '68 GTO would have had a 350CI. Now if it did have a 350CI, then someone slipped it in as a replacement.

So I hope you did not misunderstand the PHS documents and ditched your numbers matching 400CI for the engine currently in it because you will have dropped the car's value quite a bit.
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post #4 of 19 (permalink) Old 03-27-2019, 09:08 PM Thread Starter
 
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Thanx guys,I'll recheck the PHS documentation.I still have the original engine,manifolds,rear and drum brakes
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post #5 of 19 (permalink) Old 03-27-2019, 10:00 PM Thread Starter
 
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Ok,the PHS doesn't really help.I checked engine block#....386602YN,I think what kinda confused me was it had a 2 barrel...vin# 242678B123701
Checked a few engine code sites and it got really confusing saying some codes overlapped.Pretty obvious I ain't the sharpest knife in the drawer
.....this morning found #9790347 next to timing marks

Last edited by HotRats; 03-28-2019 at 09:59 AM. Reason: Additional info
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post #6 of 19 (permalink) Old 03-28-2019, 04:27 PM
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In '67 and '68, an 'economy' 2bbl 400 engine was offered. It had lower compression (8.2:1) heads, TH400 auto, and usually a 2.56 rear gear. Not many made, but they are out there. And they are usually cream-puffs, as they were never driven in anger like the higher HP 4 speed cars were.
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post #7 of 19 (permalink) Old 03-28-2019, 06:18 PM
 
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Ok,the PHS doesn't really help.I checked engine block#....386602YN,I think what kinda confused me was it had a 2 barrel...vin# 242678B123701
Checked a few engine code sites and it got really confusing saying some codes overlapped.Pretty obvious I ain't the sharpest knife in the drawer
.....this morning found #9790347 next to timing marks

Pretty simple to ID. Assume you jammed block number with the 2-numeral engine ID code. YN is for a 1968 265HP 350CI.

Next form of ID is to look at the center exhaust port on each head. You will find a 2-digit number. 1968 350CI will be "17".

That is basically all you will need to ID the engine unless someone had swapped parts around and done a mix & match.
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post #8 of 19 (permalink) Old 03-28-2019, 06:40 PM Thread Starter
 
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Ok,so my last question,can since this is a same year car/ motor can this be a freak one of a kind mistake bye the assembly line?
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post #9 of 19 (permalink) Old 03-28-2019, 06:44 PM Thread Starter
 
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Also the rear had highway gears 2:92(?)
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post #10 of 19 (permalink) Old 03-28-2019, 07:09 PM Thread Starter
 
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Or more than likely an optional choice
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO General Discussion

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