428 PI Exhaust Manifold Questions

[lockfish]

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

[Coralsnake]

No flapper and yes they appear to be dated too early

[lockfish]

Thanks Pete.  Are the cast numbers correct?

[68blk500c]

No flapper and yes they appear to be dated too early

I don't agree with your flapper answer. 

[Coralsnake]

Hmmmm,

[TLea]

No 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 

[Royce Peterson]

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.

[Coralsnake]

Interesting I recall #1628 a Jan car - no spacer

[warwick]

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.

[lockfish]

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

[Poor Ron]

I think the ID # are; C6OE-9430-A & C7OE-9431-A for unibody cars, such as our Shelbys.

[Royce Peterson]

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.

[shelbydoug]

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.

[Royce Peterson]

The date codes are 6B3 and 6B2. Those dates are in February 1966 - Mustangs were not even getting FE engines then.

[lockfish]

Guys, I appreciate all the feedback and knowledge.