Hi again,
yes there is a difference in the crankcase area, this is the external one I have just mentioned and as I said this happened in 1974 not 1973 as people are getting confused with.
The difference consists of three verticle ribs behind the oil pump, this did not get fully phased in until at least 1976 for all 202 engines, until this time it was only one of the two foundry areas that were doing this.
As far as CAC casting engines until I see some physical eveidence otherwise, I will stick to them being cast at Holden, makes no sense for two factories next door to each other doing the same work.
Specifically as far as the Bathurst 73 engines are concerned these were made in at least 4 batches of about 40 each totalling 166 engine not 150 as commonly believed,
this can be varified by looking at the build sheets and the engine number change over number in all Holden's parts books,
the 150 list is a flored document!!

The Bathurst 73 engines ( all of them ) had the exact same dates as HQ and GTR and S model 202 Toranas, are you saying that every time they suposedly made engines elsewhere they made engines on the same day in Holden?

I suspect that getting engines from CAC is another confusion of the facts and years.
I am not saying that the engines were not at CAC!
I am saying that they did not cast them!

It would be perfectly lodical if Holden machined their blocks as per normal to a almost finished product, then sent them to CAC to have the valve cut outs put in.

The valve cut outs were not something that Holden was likely to have been equiped to do in small batches of aproximately 40.

It also makes sense for blocks selected at this final stage as an unfinished block would be almost worthless!

I am a first class Machinist by trade and have studied metalurgy as part of this trade so I understand the issues involved here.
Efficiency of time is also an important consideration when machining so this plays an improtant role, and the larger your business the more criticle this becomes.

I hope this makes it more clear,

Mike







Purpul Police

Hi,
I would like to have the source of that article, if possible.
Unfortunately some well known motoring writers are known to get things wrong, one article I have about Bathurst 73's has about 6 things wrong, some of these things were very wrong, like the bit about having extra body strengthening, the truth is all 1973 6cyl Toranas had this feature! I won't go on but you get the picture!
I would prefer to use factual phisical caracteristics to detirmine things, and at this time there is no physical features that are any different to HQ blocks.

Mike

Purpul Police

Thanks HK 1837,
perhaps there may be some confusion between track cars and general production ones too.

A well known motoring writer certianally fell into this trap quoting Monaro brakes for the Bathurst 73 XU-1, when they in no way fit a normal street version!
Whereas this could well have been a track car thing with 14" wheels!

I have just last night read in the latest AMC magazine that Dick Johnson quietly used NASCAR blocks in his Ford, perhaps HRT did something similar with subsitute blocks and that is why we can't find anything in General production engines.
( I know Dick Johnson drove a XU-1 in 1973 )

I have 1971, 2, 3 and 4 QL blocks and a stuffed Dec 73 NP here here so I will have another look for an earlier change as you suggest.

Thanks Mike

Purpul Police