SAAC Forum

The Cars => 1968 Shelby GT350/500/500KR => Topic started by: lockfish on April 12, 2024, 01:33:39 PM

Title: 428 PI Exhaust Manifold Questions
Post by: lockfish on April 12, 2024, 01:33:39 PM
My 68 GT500 (PI) has the following cast numbers on the exhaust manifolds C6OE-9430-A & C6OE-9431-A and the date codes are 6B3 and 6B2.  Are these correct?  The dates indicate the would be from a earlier Ford. 

Also, did the spacer have the flapper?

Thanks

Title: Re: 428 PI Exhaust Manifold Questions
Post by: Coralsnake on April 12, 2024, 02:00:36 PM
No flapper and yes they appear to be dated too early
Title: Re: 428 PI Exhaust Manifold Questions
Post by: lockfish on April 12, 2024, 02:02:59 PM
Thanks Pete.  Are the cast numbers correct?
Title: Re: 428 PI Exhaust Manifold Questions
Post by: 68blk500c on April 12, 2024, 03:03:06 PM
Quote from: Coralsnake on April 12, 2024, 02:00:36 PMNo flapper and yes they appear to be dated too early

I don't agree with your flapper answer. 
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Coralsnake on April 12, 2024, 05:05:47 PM
Hmmmm,
Title: Re: 428 PI Exhaust Manifold Questions
Post by: TLea on April 12, 2024, 05:09:05 PM
Quote from: 68blk500c on April 12, 2024, 03:03:06 PM
Quote from: Coralsnake on April 12, 2024, 02:00:36 PMNo flapper and yes they appear to be dated too early

I don't agree with your flapper answer. 
I don't agree with your disagreement  ;D
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Royce Peterson on April 12, 2024, 05:10:30 PM
The flapper was used on engine assemblies dated up through a date in February 1968 which means most of the GT500's would have them. The rest of the GT500's would have the spacer but those would be in the minority since the GT500KR replaced them.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Coralsnake on April 12, 2024, 05:24:28 PM
Interesting I recall #1628 a Jan car - no spacer
Title: Re: 428 PI Exhaust Manifold Questions
Post by: warwick on April 12, 2024, 06:19:04 PM
I have C60E-A on Drv and C70E-A on Pass (dated 8C14/8C16) on an early May 427 GTE build (eng assembled March - 8C30). The GTE is a Dearborn build. I would assume a GT500 built on approx same date-if GT500s were that built that late would be the same. There is NO spacer or control valve. The pass side manifold is machined for exhaust donut. The H-pipe is the later PN.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: lockfish on April 12, 2024, 06:34:21 PM
Interesting about the spacer and maybe mine with the flapper is correct for my Feb 68 build date.
Now back to my original question. Are my cast numbers and dates correct for my early 68 GT500?  It seems they likely are from an older Galaxy or Fairlane. If I'm right I'll be looking for a correct set. Thanks
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Poor Ron on April 12, 2024, 07:29:06 PM
I think the ID # are; C6OE-9430-A & C7OE-9431-A for unibody cars, such as our Shelbys.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Royce Peterson on April 12, 2024, 08:12:26 PM
I think the casting dates are too early for the car. Ideally the casting dates for the exhaust manifolds need to be around 6 - 8 weeks prior to the car being assembled.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: shelbydoug on April 13, 2024, 08:37:55 AM
I agree they are too early but the date variation seems to change depending on what time of the year the car was built?

Early in production seems to be the largest variation and late could be as little as a week to ten days difference?

I don't know what causes the variations but that is what I have seen as best as determining originality to the car on something that is over 50 years old.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Royce Peterson on April 13, 2024, 10:26:34 AM
The date codes are 6B3 and 6B2. Those dates are in February 1966 - Mustangs were not even getting FE engines then.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: lockfish on April 15, 2024, 05:19:14 PM
Guys, I appreciate all the feedback and knowledge.
Title: Re: 428 PI Exhaust Manifold Questions
Post by: Royce Peterson on April 15, 2024, 06:08:30 PM
Quote from: Poor Ron on April 12, 2024, 07:29:06 PMI think the ID # are; C6OE-9430-A & C7OE-9431-A for unibody cars, such as our Shelbys.

True, the RH manifold was revised for 1967 since the one used in Fairlanes / Comets for 1966 will hit the floor pan because it is too long for a Mustang / Cougar application. The 1967 Fairlane / Comet got a revised H pipe so the new manifold would work.