[kyle_blake]

Hello,

Happy holidays everyone! Thanks again everyone for helping me the last 2 decades learning about pontiacs!

Super excited! I just got a numbers matching complete 428 with vin 0300687 XF – 1969 BLOCK ( GRAND PRIX 4 BBL AUTOMATIC – 370 HP - #9792968 date code K278)

Doubt anyone is looking for that engine to match their big car? Really excited to take it apart and wanted to ask questions regarding the exhaust manifolds on this engine:

How can I tell if these came original on this engine?

Is there date codes on exhaust manifolds? Assume no.

Are these manifolds the same (ID) as the 1969 GTO ram AIR manifolds?

I heard these are out of stock for most people to buy right now?

[steve25]

The 69 B body cars with the 428 HO motors used the same exh manifolds as the 69 F body cars with Ram air 400 motors.

Left hand 9779495

Right hand 9797073.

It appears your left hand manifold is for a 67 A body car.

[kyle_blake]

Hmm ok so most likely not repo , interesting. I heard the RH manifold has the # on backside of it facing block, so I'll need a mirror to see that. Ok so someone put these on them back in the day. Not original to block . ok cool . that is great

[steve25]

I would be excited also that you have a 4 bolt main motor.
What is the head casting number ?

The XF 370 hp motor should have 62 castings on it and in side the block should be a full length windage tray and the 066 cam with a N stamping.

[kyle_blake]

Hi, my brother and i spent some time in garage tonight!

i have #62 HEADS DATE CODE K278 / BLOCK IS #9792968 date code K278

For sure this is matching #'s engine! The carb ID also confirms it. but...like you said the exhaust is not from this engine...

The intake manifold is as well 9794284 K228

We took off exhaust and found the other #.9797072..

are you sure it is 9797073????

ps -> when we get down to windage tray and cam and n stamping I will be right back here

thank you!

[johnta1]

9797072 is for the 69 GTO RA III and the 9777646 is for the 1967 GTO RA

What's the partial VIN on the block?

[kyle_blake]

thanks for helping decode manifolds!

too bad not a matching pair . are they worth the same price as after market?

partial vin hmm not sure what denotes a partial vin?

next to XF is 0300687.. s/n is 29P188979 i think?

[johnta1]

The 29P188979 is the partial VIN of the block. It would be the partial VIN of the car it came in.
(the 9P188979 sent to PHS would get the stats/options for that vehicle)

Sounds like a good engine to use.

[JSuchma]

Originally Posted by kyle_blake

thanks for helping decode manifolds!

too bad not a matching pair . are they worth the same price as after market?

partial vin hmm not sure what denotes a partial vin?

next to XF is 0300687.. s/n is 29P188979 i think?

In no way am I trying to rain on your parade, and don't take this the wrong way but after looking at the pictures you posted of the manifolds, I think that they are reproductions.

1. After half a century there should be a lot more rust pitting and errosion to the casting numbers. The numbers are just too crisp and legible.

2. I also note that the one manifold has the casting number set on a pad, which I have never seen on any Pontiac RA exhaust manifolds.

This is just my honest opinion after having many original RA manifolds over the years.

They are still worth $$$ and you have a great find!!!

[kyle_blake]

Oh, ok that is an option i never thought existed - vin searching using the engine s/n. cool..

Well i took off the rocker nuts and all of them used same socket size except for two nuts.

small green a/f liquid in the side of heads but figured that came from transport of engine as it isn't milky.

next up intake and heads come off! can't wait!

[kyle_blake]

jchuma - > totally could be 1 or both, when i was researching i saw that ! aftermarket were putting the orig #'s on them. ( like on a pad or rectangle around it ) i was curious as to what differentiates oem vs that after market but yes these are in fantastic shape.

would be nice to know that's for sure

[P@blo]

Not that I can be much help on the manifolds, but congrats on getting a sweet 428 Kyle. You got a real gem there pal.

Happy New Year.

[kyle_blake]

hey pablo, long time no talk! thanks man, yah just ran the distributor # and it's a match 1111959 8L21

happy new year!

[jerry455]

The 1969 Grand Prix was not a B body, it is G body. Very similar to the A body, slightly longer wheelbase. Those manifolds could have come on that motor in that car. It is a cool find.

[242177P]

They're definitely reproductions (note no heat flapper)

Originally Posted by jerry455

Those manifolds could have come on that motor in that car.

Wrong, 69 GP would've used the long branch manifolds.
They're right for Kyle's A-body, and that's a GOOD thing.

[kyle_blake]

Hi, oh that's a good point, I never thought of them not having heat flapper on each one.

That should pretty well conclude these are aftermarket then...

I could use these on my 69 gto and from an "appearance" point of view it is "period" correct. It could of come on my gto if it was a ram air 3 or ram air 4 engine. YS 350 would not.

I'm gonna call that answered. Repo's manifolds, mismatch 67 & 69 #'s for those guys who might want to buy them.

I think Jerry meant it could of come on my A body GTO. As for G and B , all I know is this engine is in all likelihood a GP engine.

I tore rest apart with a friend and will post some more pics in a new post.

[grivera]

Originally Posted by jerry455

The 1969 Grand Prix was not a B body, it is G body. Very similar to the A body, slightly longer wheelbase. Those manifolds could have come on that motor in that car. It is a cool find.

Wouldn’t a 69 GP have come with long branch manifolds instead of RA manifolds?

[steve25]

A 69 GP with a 370 or 390 hp 428 would have come with the long branch Exh Manifolds , these would have been the same ones used on the first generation F body cars with the ram air option, so you decide.
Do you call them long branch or ram air?

[JSuchma]

Originally Posted by 242177P

They're definitely reproductions (note no heat flapper)


Wrong, 69 GP would've used the long branch manifolds.
They're right for Kyle's A-body, and that's a GOOD thing.

You can't use the lack of a preheat flap as an indicator of a repop. I have a pair of NOS, 1970 only, 3 bolt head flange RAIII manifolds that do not have the preheat flap. BTW, all repops have the 5 bolt head flanges.
FWIW.....This pair came from a long time friend of mine that worked at a Pontiac dealer in the late 70s.
The flash rust on them is the result of our very humid climate. The have never been bolted to a head.

[jerry455]

Sorry, I thought a 69 GP was a G body, similar to the A body. I thought it would have used the same manifolds as the A body.