Here's the start of a few questions to keep your minds active.

I have recorded all three of these cars for the first three questions. Take a stab at the compliance month for all three?

Q1. AHX00001A. Compliance month? It was a 202 3spd manual Holden panel van. Answer: 3/76. Completed 2/4/76

Q2. AHZ00001A. Compliance month? It was a standard HZ GTS sedan. Answer: 6/77. Completed 18/7/77

Q3. AWB00001A. Compliance month? It was a 3.3 4spd Kingswood. Answer: 9/79. Completion planned for 9/9/79. I think this was the pre-pilot, built just before the Woodville body tryouts followed by online pilots.

Q4. HR advertised power vs GM20 (SAE gross hp). GMH advertised the HR 186 X2 as 145hp (plots say 144hp but close enough). Take a stab as to what it's real SAE gross figure is? GM20 is the laboratory SAE gross figure as GM used for its engines. (Note this was normal for GMH up until basically HJ/LX where thy rated the engines at the SAE gross figures, I just have the dyno plots for HD and HR straight off Fred James's dyno reports, even have the engine numbers of the engines tested). Hint the GM1 (as installed SAE net) figure for the HR X2 186 is basically 100hp. Answered in later post.

More later.

Edited by user Thursday, 2 April 2020 2:14:45 PM(UTC)  | Reason: Not specified

Way earlier.

Yes and no. The curve does show 124hp@4400 but the peak is just over 125hp@4600rpm. The original Experimental Engineering dyno report hand drawn curves shows basically 125hp flat between 4200-4600rpm, but what appear to be the official graph power curves shows 125hp@4600rpm.

BTW the engine number of the X2 tested was 186K72383.

Is q1 a promo car from 12-75

July 1977?

I think you're right on 7/77 on q2 8D11

They were the same advertised figure of 145hp, but the X2 GM20 SAE tests for this engine show what I stated. The hand drawn GM20 (SAE corrected to 60deg F) curve actually shows a peak of 125.5hp @ 4300rpm crossing the 125hp line at a fraction under 4200rpm and again at 4400rpm but staying there until dropping off at 4600rpm. The GM1 test (SAE net corrected to 100deg F) shows a peak of 102hp at 4600rpm. These are the official GMH dyno tests attached to the final test report for the 3 main HR engines (161HC, 186 and 186 X2), done between 26/7/66 and 6/9/66. Report dated 13/10/66. The other two engines were 161R55717 and 186A55719.

I have since found another engine spec comparison chart that confirms your figure.
HR 186 X2 and 186S engines are both rated Gross HP (Test 20) at 125HP @ 4200 rpm.
GM Test 1 = 101HP @ 4600rpm

Look at the WB HDT power vs the VH SS HDT same engine but what of the exhaust ?

I know that the Ford XC ZH V8's had an updated jetting and spark timing, same power ratings but they did perform much better from that point on, just like the Holden's did as with the up date HZ Holden's.
XC and ZH 4.9L were points and up date went electronic like the 5.8L were.
The XC and ZH 5.8L did 195KM/H and the up date did 210KM/H. I have seen it for myself.

I think that HX 5.0L were flat 185KM/H.
Just look at the Holden HZ dual exhaust and then look at the VB duel, I would think that the HZ flows better.

Look at the HQ to HZ 3.3L and then look at the WB 3.3L ute and then look at the VB 3.3L, I would think the WB flows best and the next is the VB with the HQ to HZ being just crap.

DIN is on a Dyno in reality hooked up to the engine with all exhaust air filter, water pump and all etc just like it would be in a car within a set temp, in fact ECE I think it's called is a more advanced than DIN. GMH went to DIN with the VB Commodore and then to ECE with the VZ or about that time.

Max HP figures are one thing but any serious person needs a graph to understand what's going on, look at a HT GTS 350 4speed and drive that and then drive a VX SS 5.7L and you will see a huge difference in how the power comes on, the Old HT has massive grunt down low that a VX 5.7L does not have at all, you have to wait for 4000RPM to come on until the 5.7L even comes alive and it has nothing on a HT 350 until then.
So even if the VX SS did have the same max HP as the HT GTS350 one would not have a clue by reading the max HP as to what is truly what, they are both totally different in how they perform.

Look at a Ford XF 4.1L OHV EFI and a 1988 3.9L OHC the 3.9L has nothing on the 4.1L down low, if you have ever driven a 1988 EA Falcon 3.9L 3sp auto you would know that they were totally pathetic in taking off the line, you would be flat out spinning the wheels on grass they were that shockingly gutless until the revs got up and then they went well. but you can not see that fact on paper with the max HP shown.
So if you had a XF from new and you went and up dated to the new EA and looking at the brochure and seeing the power increase you would be impressed but when you drove it you may be totally shocked to fine just how gutless it is to get it off the line, I am sure that a EA Falcon 3 sp auto could not even make it up my uncles drive way into his garage and driving around his town of hills such a ting would be out of the question, even tho he drove a stock 138 EJ holden and a XM 200 Fatura 2sp auto around the place.

Now lets say we look at someone who has a car and wants to know what to do to it so as to make it run more efficiently, well one may start with the exhaust and lets say the car is a HG 253 well the best value is just go to a 2 1/4 single with a free flow muffler for a start. now they will feel the difference easy but what if they ask for proof of this before they fork out, well I could show std is 131hp-fw and this exhaust system makes it 154hp-fw and it's all a increase of Torque and power over the whole rev range, but a graph would clearly show such, but it will be louder than stock, now if they don't want the extra noise well then it's a twin 2in exhaust system they will have to go for the same efficiency advantage, but quiet.
Now one may ask how come the 253 will only have 154hp when Holden say 185hp, well them figures are fantasy land figures and nothing to do with reality worth talking about. No engine is of any practical use siting on a stand with no air filter exhaust or the rest that goes with it when in a car.