[Pontiyak]

[QUOTE=Half-Inch Stud;5683760]Parted-out a 69 428 HO Bonney Conv back in the day (80's) relax, it was rusted. Had the Towing package. The TH400 tag was PC and had 3/8" cooling lines.

What would the 69 GP 428HO TH400 code be? PD?,, PC?? not PW.. [QUOTE]

Half Inch Stud for a 428 HO big car the code would be PC. If a 428 it is a PH.

Originally Posted by poncho-mike

I have a 1969 PR that came with a 1969 WG motor, but I don't know what rear end that car came with.

When I responded to this thread back in 2006, I mentioned I pulled a 69 WG out of a 1970 Firebird. The engine and tranny were separated when I pulled the engine out. I recently started trying to inventory what parts I have, and in the process found a TH400 marked 1969 GP 428HO. The trans tag tag is PR. I think this is the tranny I pulled out of the 1970 Firebird, but I can't be sure.

If PR was used with 3.90 gears, I could pull the VIN and you could PHS it. It's my understanding the GP was dismantled in CA probably at least twenty years ago.

Mike

First Mike thanks for replying to help my recovery. LOL

Mike the PR you have is correct for the 428 HO in a Grand Prix if a 69 TH400.
But no way to tell way gear that car was factory equipped.
PW is code for 400-4V Grand Prix.

On that tranny should be the VIN, on passenger side around mid area above where oil pan bolts goes by tranny case.
If you see VIN. PM me the info. I will PHS if seems correct.
Match up to that WG motor to that PR transmission ?
If its a 1969 WG its a 428-360HP manual transmission big car.
See codes below.

1969 WG 428 360 M 4 FULL
1969 YL 428 360 4
1969 YH 428 360 A 4 FULL
1969 XE 428 360 4
1969 XJ 428 360 A 4 FULL
1969 XK 428 360 A 4 FULL
1969 WF 428 370 M 4 GP
1969 XF 428 370 A 4 GP
1969 WJ 428 390 M 4 FULL
1969 WL 428 390 M 4 GP
1969 YK 428 390 A 4 FULL
1969 XG 428 390 A 4 GP

Thanx Dave

[Half-Inch Stud]

Okay;

Big Car 428HO got PC TH400s
GP 428HO got PR TH400s

[north]

Unlike 69 big cars where the regular and HO 428's had different auto trans codes the 69 GP 428's (370 and 390HO) both had the same auto transmission code. I'm not in front of my books so I don't recall the code but I do know that they are the same.

[428ho4spd]

Here's a scan of the codes from the '69 service manual...

[north]

Originally Posted by poncho-mike

I have a 1969 PR that came with a 1969 WG motor, but I don't know what rear end that car came with.

When I responded to this thread back in 2006, I mentioned I pulled a 69 WG out of a 1970 Firebird. The engine and tranny were separated when I pulled the engine out. I recently started trying to inventory what parts I have, and in the process found a TH400 marked 1969 GP 428HO. The trans tag tag is PR. I think this is the tranny I pulled out of the 1970 Firebird, but I can't be sure.

If PR was used with 3.90 gears, I could pull the VIN and you could PHS it. It's my understanding the GP was dismantled in CA probably at least twenty years ago.

Mike

Hi Mike, I bought both that WG and a XG HO from you last year. I haven't touched the HO yet but I did rebuild the WG. It was in beautiful virgin shape and despite being a 360 horse "Bonneville" 428 it had the big valve 62 heads (instead of the small valve 46 heads) and 4 bolt mains. It also still had its original 067 cam. In effect the WG is identical to an automatic HO engine with the exception of the longbranch.

[north]

Originally Posted by 428ho4spd

Here's a scan of the codes from the '69 service manual...

Interesting... wonder what the PA trans is about? I suspect it was never produced. probably the code for a 68 non HO 428 I guess?

[poncho-mike]

Pontiyak,

Since I'm more Firebird oriented, I don't get to this thread very often. I mis-spoke when I said I pulled a 69 WG out of the Firebird, it was an XG.

North,

Glad to hear the engines worked out well. Both were running engines. The XG was a beast to drive in a Firebird. The idle wasn't bad, so I assume it wasn't running a big cam.

The WG was also a running driving motor, and I don't think it had ever been rebuilt. I ran a compression test of it when I first got the car, and compression on all cylinders were right on the money. The H-O book said it should be 4-bolt main, so the book was correct. Have fun with it.

I still have a few 428s left if interested, one SR block and a couple of XF (370HP) Grand Prix codes.

[north]

I already have 7 69 Pontiacs running 428's plus that XG in waiting but I have a friend looking for preferably a 69 2 bolt 428 XH. If you could pm me your contact info I'll send it to him.

The WG was in amazing shape inside, bearings were factory original and could have been reused, still no copper showing. Only wear was on a few cam lobes. Especially amazing since the oil pick up was blocked solid with the remnants of the original timing gear teeth, probably been there 40 years. Almost nobody followed the proper procedure of removing the pan and cleaning it when replacing the timing gears.

[poncho-mike]

If my memory is correct, I have a really nice YH 428 2-bolt short block assembly. I took the heads off, greased it up and bagged it for long term storage. It was running when taken apart, but since it had the small valve heads I didn't keep them. If an engine had good heads and good block, I tried to keep it together. But stuff like the 360HP 428s, 70 360HP 455s, and 71-74 low compression 455s, I removed the top end and distributor so I could put them on a shelf.

BTW, the XH was a 400 350HP Grand Prix engine. I think you meant to say YH.

I have seen several cars with the nylon timing chain gears. My favorite all time tow vehicle was a 78 Suburban 3/4 ton 454 with a special order rear end (3.21 gears). I towed a car all the way from Atlanta to Raleigh one weekend and parked the Burb in my driveway with the trailer still attached. I came out the next day and it wouldn't crank. It didn't sound at all right. I checked it for spark, and I had none. The way it sounded when it turned over just didn't sound right, so I popped the distributor cap and saw the rotor didn't turn at all. I thought I had broken a timing chain, so I pulled the timing chain cover. I found it still had the original nylon timing gear but I have no idea how it managed to run since the nylon was long since gone. I pulled the pan and found the oil pump pickup partially blocked. I replaced the timing chain and installed a high pressure oil pump and drove it another 120K miles. The engine was still running great, the rear end went out on it.

[north]

Correct about the code, YH. I'll mention to him about that block, those 46 heads are the same as used on the base Catalina 400-290 high compression 2 bbl.

[pontorquer]

http://www.ebay.ca/itm/1969-Pontiac-...lV8Gjr&vxp=mtr

This 1969 GP is a real 390 XG 428 car, I could have bought this for $600 but he was quicker than me !

[428ho4spd]

Originally Posted by 'ol Pinion head

Speaking of A/C, anyone have an idea how many of the 706 '69 428HO GrandPrix with C60, were also optioned with Automatic Temperature Control C75???

My current SJ has this combination and I personally know of three others, one being a Model J.

[north]

I don't imagine anyone has or will collect that data from the PHS's but just from seeing cars over the years I'd say that about 1 in 5 GP's with AC have ATC.

[428ho4spd]

That sounds about right. Funny, of all 15 or so '69 to '72 GP's I had up until 2009, none had ATC. Since that time the last 4 of 5 did.

[north]

The presence of ATC on a car might have helped hasten its demise in the late 70's and 80's when these cars were one step away from the scrap yard. An ATC failure could easily doom a car, who wants a car that doesn't have working ventilation and that no one can fix!

Also unsurprisingly ATC seems to be most common on very high option cars. It doesn't sound that expensive at $80 but that is $600 in todays money on top of a $420 AC option ($3,300 today) for a probably unreliable item of rather dubious added value.

I have two cars with it, an SJ and a Bonnie Brougham. The one in the Bonnie works great now and only needed an NOS fan control switch but my SJ unit was dead and its nothing obvious like a bad fan, relay or switch etc :-(

[428ho4spd]

I agree. It is a very complicated system that is not easily diagnosed or repaired.

In most cases that is true. One exception would be the '69 Model J I sold back to my friend last summer... it was a strange optioned car (see attached invoice), no rally wheels or even a radio!

Of the last 4 GP's I've had with ATC... all seemed to function properly through the different modes, but two of them made funny noises when when changing temp which was a little annoying. My current GP has the electric rear window defogger which also ties into the a/c system with additional relays making it even more complicated.