actually, having spent a number of years working in the engine and transmission plants at Port Melbourne, I would say they had the 'capability' but not the desire.

Their lathes, boring machines, tapping machines.. all totalled an actual engine manufacturing line. Stick a 'fettled' raw v8 block at the end that says 'start ...
and maybe ( I forget actually how long) a naked new clean fully machined engine block (with matching caps) would pop out the other end.

That end would be hooked on the conveyor and wizz across the plant to start the assembly process. With machined (balanced) crank waiting and pistons
already on rods, the machined block would again drop on an assembly line and have the bits fitted to make an engine.

I said capability ... but not the desire. Those various machines could be set up to do just any sort of machining, drilling, threading operation but unlike
todays computer controlled CNC machining centres which take very little, even zero setup and can do up to 16 things * on a piece of metal in one pass,
these GMH production machines took hours to setup, to change setups and first-off scrap rates were horrendous whilst engineers got things 'accurate'.

Why do it... ? when the time for setup will probably be longer than the time to make a batch of 'special' heads?



* I still work in manufacturing.... for a company that makes 3-4 million metal parts a month. All of those go thru computer controlled machining centres
(vastly bigger than the GMH machines) ... feed in a blank piece of metal and up to 16 drilling, threading, boring, indexing, chamfering, surface finish
operations happen in the one place... in one machine. VERY quickly. You get a complete part out the other end that has been laser checked for accuracy...
most dimensions are down to 0.001mm and scrap rates? Month of May ( I got the results today... ) how about 0.03% of all input??
On a machine that makes more than 300,000 parts a month.. break a tool and it takes 3-4 minutes to replace and set up for the next part??
About 20-30 mins ...

Yella Terra was a brand. Perfectune was a Company. GMH (and HDT) had Perfectune do the machine work for them. They would have used whatever valves, springs etc that were supplied to them by GMH. The L34’s valves would have just been off the shelf GM valves.

I’ve never heard of HQ heads being any different to HT-G heads other than the addition of the extra accessory hole on the ends. However it is possible they refined the patterns.

I remember when my mate wanted to fit L34 valves and hardened exhaust seats to his VK heads, Perfectune told him to use red pollution heads as they had more material behind the chambers. I still have the heads and the intake off that VK in my shed. It was a manual 5.0L but built after they had finished building the 5000 engines for GroupA homologation, so it still had the HDT style intake but had stock heads.

There was one Magnum Ute. It was based on a white 6 cylinder Ute. They converted it to a stroker motor and Statesman interior and front. Wasn’t finished until about 87.
The blue one is a fake based on a wrecked Magnum statesman.

I came up on the Net with recorded video of Brock and Harvey interview.

I thought all 5.0L Statesman's came out with the high ratio diffs 2.78 or 2.60 std and one had to option a 3.08, why would the HZ SL/E be any different ? never heard of a 3.36 option for a statesman, why would anyone want that in such a car from factory.

A old bloke who I know had 2 of them HZ SL/E grills like new sitting in plastic above a locker some years ago, he showed me them smiling. he once had owned a Holden dealership but he is dead now. he owned every model Brougham and every year model Statesman up to WB and still had the WB when I seen him last, he was boasting about it and that he had got rid of his HZ only a year before and he put a brand new 350 chev in that back in 1979 or 1980.