[blubomber]

I think the long branch exhaust manifolds and a larger volume air intake are really the only differences between your XF and a XG coded 428.

The heads, cam, carb, transmission are identical.

Your Ram Air manifolds certainly are good substitutes for the long branches.

HO cars came with chrome valve covers and air cleaner lid.

[1oldgoat]

This car has the chrome lid and valve covers too.

[Ram4king]

I might have a positive for it. Your car is totally correct. Your getting bad info here. Never have seen 48 heads on a automatic gp. I've seen 46 heads on a automatic 428 but never 48's. I also believe the carb and cam are different on the HO. But that is neither here or there. All 428 engines when equipped in a gp have chrome valve covers and air cleaner lid.

[1oldgoat]

Thanks for the info Don. I know a little about GTO's but a little light on GP knowledge. It just seems like a decent car to make a cruiser out of and keep almost all original. My email is sda24237@gmail.com if you want to talk about the axle or I can call you later when I get off work.

[Matt Meaney]

standard gear for a '69 with A/C is 3.23. if it is equipped with a safe-t-track, it will have a "medium duty" 4 pinion case.

[blubomber]

Don,

Were #48 heads used on M/T Grand Prix cars?

#46 heads with a 10.5:1 cr were used on the std 428 in B body cars. They had a 262 carb and used a .066 cam.

B body 428HO's had #62 heads, a 10.75:1 cr, 4 bolt main caps, a 268 carb and the .067 cam on A/T cars. Almost no M/T B body cars were produced.

I have always understood that the .068 cam was only used on M/T cars

[blubomber]

chrome valve covers and air cleaner lid were std on the B body 428 HO but not the std small valve 428's. I did not know that chrome valve covers and air cleaner lid were std on all GP 428's, either XF or XG's

[428ho4spd]

Originally Posted by 1oldgoat

Do you guys know what the standard axle ratio was for a 69 SJ? There is nothing on the PHS so I am guessing it is whatever is standard for a 428 automatic with A/C.

Equipped with a/c the ratios would be either... with "no" axle option shown on the invoice 3.23 is the std ratio... if the "economy" axle was shown on the invoice you would have 2.93.

[428ho4spd]

FYI... early production '69 GP's with either the 428 engine option or SJ option were built with the limited slip rear axle prior to the bulletin released on Jan 9th, 1969... what is the production date code on your data plate?

[1oldgoat]

Originally Posted by 428ho4spd

FYI... early production '69 GP's with either the 428 engine option or SJ option were built with the limited slip rear axle prior to the bulletin released on Jan 9th, 1969... what is the production date code on your data plate?

My car is 04D production date. No economy or any other axle options on PHS.

[428ho4spd]

I've only seen a few SJ's over the years that didn't have safe-t-track listed on the invoice, your car would be another. The axle stamp for a 3.23 posi in a GP is "5F", these are fairly common if you wanted to search for one.

[1oldgoat]

Here's a copy of the PHS.

[1oldgoat]

There is an interesting twist to the story about this car. The dealer who sold this car new was good friend of my father. I was actually in that showroom in late 1969 or early 1970 as a 5 year old kid.

[428ho4spd]

Great story! Thanks for posting the invoice, always neat to see how these cars were optioned. Does your GP still have its original alternator?... it should be the "open face" self regulated 61A unit having a/c and heated rear window.

[428ho4spd]

I had a similar '69 SJ to yours back in the early 90's, here's two old photos of it...

[1oldgoat]

I don't know about the alternator. I will check it. Are they hard to find?

[428ho4spd]

Yes, they can be.

[1oldgoat]

Looks like it might be the right style but looks like a rebuilt that has had the numbers taken off.

[428ho4spd]

That looks like the aftermarket unit on my car as well. Its similar, but not the original type unit.

[1oldgoat]

What number should it have?