VK Commodore IS an 84 year model ?

Actually it is from a WB Deville. Caprice are differently numbered.

308 on both sides is about the second half of WB, VK and VL. It went to 5.0L from VN to mid VR then blank. XX4 could be 1994 too but not with 308 on the side(s).

Edited by user Wednesday, 19 May 2021 3:25:55 PM(UTC)  | Reason: Not specified

QT9019xx will be from a HZ around October to December 1977, depending upon whether it was auto or manual and which BAP it was installed in. Don't pay much attention to date codes, that is a mug's game. The engine number is the important thing, but even that is a waste of time unless you have your original. Here is an example why:

J597737 is an L31 M41 cab-chassis completed on 2/12/77. It had engine number QT899896. 21 HZ's later is:
J597892, is an L31 M21 HZ van, probably a Sandman. It had engine number QT901816, competed on 22/11/77. Next car:
J597893, also an L31 M21 van. It had engine number QT905840, completed on 23/11/77.

There is no logic to the engine numbers, and if you found these engines the casting numbers could and did vary by up to months. Consecutive engine numbers could have the same cast date or be 3 months apart.

Edit, I just had a look at Elizabeth, and can see QT901951 in a manual GTS completed 31/10/77. And QT901952 in an auto Holden ute completed 26/10/77. Plus QT901947 & QT901949 both in manual Holden vans completed 1/11/77 and 3/11/77. However there are earlier numbers in cars completed into December and later numbers in October, so it is a dog's breakfast. I don't think V8 engines were sent on packs like 6cyl engines so QT901953 may well be in a Pagewood or Acacia Ridge or even Dandenong car.

Edited by user Wednesday, 19 May 2021 5:21:15 PM(UTC)  | Reason: Not specified

Leary360 did you send a message to HQSS? He can't login atm do you want to send me the message and I'll pass it on?

If HHS says it isn't recorded it means either the dealer never sent the information back to GMH or the car was built after mid 1978.

I don't record cast dates as they mean absolutely nothing. You can get consecutive engine numbers with cast dates up to 6 months apart (rare but I've seen it, normally up to 2-3 months). You can also get consecutive cars with engine numbers 10000 apart or consecutive numbers. If you don't have your original just use any 4.2L engine from the time period as its as good as any other. I'd just put a 5.0L in it, will cost the same to rebuild and won't devalue the car over the wrong 4.2L.

Remember GMH never threw anything away if it could be used. If a block had problems anywhere from casting through to running on gas it would be put aside to be fixed later. Then put back through the process into the system and end up in a car. Most blocks ended up all good and became engines within days, then got shipped off to assembly plants. They got all mixed up at each assembly plant during the engine dress process. So there was numerous opportunities for cast dates and engine serial numbers and actual engines to end up all over the shop. You cannot predict any of it with any degree of accuracy, hence why it becomes a fruitless task, and to be honest pointless. Most people would have no idea what is correct or not. If you must have a 4.2 just find one dated in the 6 months prior to your compliance plate date and make sure it’s engine number starts with QR. at the end of the day though it’s really no more correct than an engine number starting with HR or 253H or VR or 11QR or similar. There was only one original engine number. You might find the car with a PSN one digit away from yours has an engine like say QR920000, where your number may have been QR941234 or QR899999. They really can vary that much or conversely they can be within a few digits. It all depends upon a combination of multiple factors, some already mentioned. Another is manual vs auto, they are very different engines and got used at different rates. Another is PSN in 12/77 is not a measure of adjacent cars, sometimes they can be completed a month apart which can greatly influence the engine number used, sometimes they might be completed on the same day.

yeah.. and a bloke called Brock

who used to waltz into Exp Eng at FBend, look around for engines that had
been run on dynos with good results and say .. I'll have those 2 !
(oh and a couple of diffs while I am at it)

Used to drive me nuts, as he never ever gave notice he was turning
up and I was the finance guy responsible (as a signatory) for signing
these out of the plant. He was not allowed out past the gatehouse
until I turned with the correct signed (by me) paperwork....

That is big boss GM. GMH doesn't exist anymore!