Author Topic: 68 J Code vs GT350 Engine  (Read 6027 times)

Greg P

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68 J Code vs GT350 Engine
« on: November 27, 2018, 07:54:55 PM »
I've been researching the difference between the 1968 J Code 302 4V engine and the GT350 Shelby engine.  Compiling casting numbers, etc. Based on my research and feedback / website links (like MustangTek and Coral Snake sites) from some of my SAAC friends, it appears the only difference is the intake.  J Code has the C8ZE iron casting while the GT350 has the S7MS aluminum.  Can anyone else confirm or refute this?  The one item that I really can't seem to find is information on the camshaft (for either engine).  Original part number, lift, duration, etc.  Can anyone shed some light on this for me?

Thanks, Greg P.

Coralsnake

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Re: 68 J Code vs GT350 Engine
« Reply #1 on: November 27, 2018, 08:35:09 PM »
Internals are identical. It is the same engine with cosmetic changes only. The secret was actually a higher rear end ratio, than most 1968 J codes.

At start of year, cast iron intakes and Autolite carbs were used on GT350s. In fact most GT350s received the iron intakes.

A few very late cars and cars returned for a recall received aluminum intakes and S8 carburetors.

Other than that, the valve covers and air cleaners are the only other varaiations.
« Last Edit: November 27, 2018, 08:50:48 PM by Coralsnake »

PR

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Re: 68 J Code vs GT350 Engine
« Reply #2 on: November 28, 2018, 10:23:20 AM »
On my 68 350's one had a S2MS and the other had the S7MS, I always thought they used what was on hand for the recall

Coralsnake

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Re: 68 J Code vs GT350 Engine
« Reply #3 on: November 28, 2018, 11:34:54 AM »
There was actually a recall kit. The S2 manifold is accepted, but technically not correct. if you had that I would argue you should use the Autolite carb

gt350hr

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Re: 68 J Code vs GT350 Engine
« Reply #4 on: November 28, 2018, 11:38:35 AM »
   +1 on the information supplied by Coralsnake. Pete has spent years gathering information on '68's . One of my friends who bought a '68 350 got the recall notice but only got the intake manifold , not the carb as it was backordered. He traded the '68 in on a '69 GT500 before the carb came in. So one '68 blue 4spd 350 had the big number S2MS intake with the Autolite carb.
    Randy
Celebrating 46 years of drag racing 6S477 and no end in sight.

Coralsnake

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Re: 68 J Code vs GT350 Engine
« Reply #5 on: November 28, 2018, 01:21:28 PM »
Just in case the old Road and Track article comes around

http://www.thecoralsnake.com/Curiousity

tesgt350

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Re: 68 J Code vs GT350 Engine
« Reply #6 on: November 28, 2018, 01:32:09 PM »
When did they end the use of the Try Y Headers and the Aluminum T Oil Pan?

Coralsnake

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Re: 68 J Code vs GT350 Engine
« Reply #7 on: November 28, 2018, 02:08:20 PM »
They were not used on 1968s

shelbydoug

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Re: 68 J Code vs GT350 Engine
« Reply #8 on: November 28, 2018, 04:06:56 PM »
When did they end the use of the Try Y Headers and the Aluminum T Oil Pan?

The '66 GT350 was the last to use them.
68 GT350 Lives Matter!

Bob Gaines

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Re: 68 J Code vs GT350 Engine
« Reply #9 on: November 28, 2018, 05:11:26 PM »
There was actually a recall kit. The S2 manifold is accepted, but technically not correct. if you had that I would argue you should use the Autolite carb
I agree with the above statement that the large number S2MS intake is not technically correct because it did not come with the official kit . I know Pete has seen a lot of the large letter S2MS intake . I do think it is just as historically correct under most circumstances. I have for example found more of the large number S2MS intake on unmolested 68 GT350's then the S7MS marked ones . The large number intake must have been at the least a very available intake for dealers to complete the recall. Although not the official I suspect it was a on the shelf or more available alternative if they didn't want to wait because of maybe a supply issue for the S7MS that came in the official recall kit.
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

gt350hr

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Re: 68 J Code vs GT350 Engine
« Reply #10 on: November 28, 2018, 05:22:04 PM »
  My personal observations are that the "initial" recall kits were more complete and did use the S7MS intake.  At "some point" , which I was never able to track down, the large number S2MS manifold was in the kit and the kit became two separate boxes instead of one . That "to me" is why my friend never got his carburetor , but it "could" also have been the dealer stealing his carburetor in reality.
   Randy
Celebrating 46 years of drag racing 6S477 and no end in sight.

Greg P

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Re: 68 J Code vs GT350 Engine
« Reply #11 on: November 28, 2018, 08:49:10 PM »
Great feedback.  So to be clear:

Coral Snake:  Are you saying that the C8ZE intake was also used on the GT350 prior to the recall?  So that would be correct or depending on the recall kit it could also be the S7MS or the S2MS?

All.  What is the correct cam part number for the '68 J Code?

427heaven

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Re: 68 J Code vs GT350 Engine
« Reply #12 on: November 28, 2018, 09:15:36 PM »
If you are looking to make your car the way they were, it used stock 302 engine components. 2v-4v used same cams no performance cams came originally with those engines. Any auto parts or engine shop can get you a stock cam. Good Luck!

Coralsnake

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Re: 68 J Code vs GT350 Engine
« Reply #13 on: November 29, 2018, 06:37:32 AM »
Quote
Coral Snake:  Are you saying that the C8ZE intake was also used on the GT350 prior to the recall?  So that would be correct or depending on the recall kit it could also be the S7MS or the S2MS?

Yes, the cast iron C8ZE is correct for the GT350s prior to recall.

Yes, it would be correct. If you are going to say the car was recalled, a S7MS is a better choice, but a S2MS will be oksy.


Coralsnake

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