Apologies for being a luddite and not knowing how to quote previous posts, but Castellan mentioned the 253s had a Carter carby.

I thought all 253/4.2s (up until the blue motors) had the WW Stromberg fitted, and Carters were the realm of the Valiants and Fords?

I have a dead stock 10/74 HJ one tonner (manual) with a 4.2 and the compliance plate has ADR 25, 28. No mention of 27. Were the tonners and other commercials exempt from emission legislation regardless of engine?

And having driven a number of 308s (Q, J and Z) back in the day, the HJs were indeed a standout. And I have nothing but respect for the writing and views of Tuckey, Robinson, Lake, Mackay et al. I even miss the musings of "Our Man Higgins".

Sep 1973 the Falcons lost the 351 4V heads and lost the open oil breathers and got the PCV system as did the HQ in Sep 1973.

How, or may I say why do Holden use ECE power figures now and why did they use DIN from 1978 in the VB, over the old Gross HP figures, are they backwards in doing so ? should they go back to Gross HP figures.

If I were into testing cars I would not print the test if the car was a bad example, it's just bad business ethics, that no one should stupe too.

There is the case of the same engines that perform well and the ones that don't out of a model as well, that one can deal with as well.

The HJ 308 having the extra compression this works out too more power in SAE gross figures as the power goes up because that's how they work out the power and that's why the 250 HP rating and nothing other than that.
Look at the other Holden engines and do the maths with low comp engines and high, bang that it, that's all it is to it.

Falcon GT with 4V heads had a compression rating of 11:1 and the GT=HO PH2 and PH3 has the same rating, or may we say that is the figure reported ? so that's where the power figures come from, they are rated the same as the GT and they could get away with it as such, but they could not get away with it if the rating was in Net or SAE or ECE HP figures.

Look at it this way, I have a 202 red engine say, stock as a rock, now I am going to put a 173 head on it, and here we have more power according to SAE Gross HP figures, we have just jumped from 9.4:1 to about 10.5:1 I think it is, now what if we go down to 7.8 ?
Here is a HX-Z 3.3L manual high comp is rated at 81KW and the low comp is 76KW.Gross
Here is a VB 3.3L manual high comp is rated at 64KW and the low comp is 55KW.DIN
They are the same engines.

We can see that the twin exhaust makes more power on the 253 and 308 from the VB commodore on.
So with a HT to HJ 253 we have a rating of 185HP Gross, now we know the HJ 253 has a smaller cam for sure so it must not have the same power ? and if we have the std exhaust or the N10 holden twin exhaust the power must increase for sure but with SAE Gross it does not take account of such a thing and when we look at the 307 Chev and the 327's and 350's and try to work it all out it can get all a bit out of hand to the facts.

No factory Holden with a 307 engine out performed a 308, just like the Falcon 302 V8 could not out perform a 308 up to a XB that's for sure and there is a good reason why it is so. Maybe a XT GT could.

Yes, 9/73 for GMH too I made a mistake in the prior post with 9/72. 9/73 is when GMH introduced all their new clean air engines (with the sticker on the sunvisor) except for the delayed batch of the final XU1's (delayed due to the special engine I believe). However Ford and/or Chrysler weren't ready and ADR27 didn't become mandatory until after 3/74 (when HQ's chassis prefix went from DHQ to EHQ).

Gross hp is the only way you can compare engines, once they are quoted net it becomes a dog's breakfast for engine comparison purposes. Gross is a level playing field with no accessories which in themselves can create large variations. Net is better for vehicle comparison. I think it became mandated, happened in the USA in 1972 and a few years later here.

Correct, HJ 308 had more power, it was due to a compression increase. This is basic engine 101. It was a far superior performing and powerful engine than the HT-HQ engine, so much so it saw the death of the imported 400ci SBC engine in HJ and the requirement of the TH transmission.

Those Ford figures are smoke and mirrors, but you can play that game with any hp figures you like. GMH did it with L34, 1973 XU1 plus they never changed the published hp figures for the McKinnon GTS327 engines (240hp real, earlier were 250hp) of the final HG GTS350 engines. GM did it with the LM1 engine and the ZL1 plus others. We are talking advertised hp here, not real gross hp.

Power changes with compression, and net figures will be lower than gross, again engine 101.

That is right, gross is in a controlled environment, engine has exhaust headers but no exhaust. The gross figures make it easier to compare the engines, takes the accessories and exhaust out of the equation. Net allows you to compare the actual cars, but as to comparing engines gross is the go.

Correct, a stock 307 HK-HG has less power than a stock HT 308. Put N10 dual exhaust on either and you would get similar gains in installed hp on both. However the comparison is unfair as the 308 got a far superior carby and higher compression. On a 327 the Quadrajet was worth 10hp alone on the 1967 engine over the earlier 1966 4BBL (230hp vs 240hp). The 2BBL 327 from 1967 was 210hp and the 4BBL was exactly the same engine other than for the Quadrajet and manifold to suit and it was 240hp. The 1968 307 was 200hp (GMH gave it 210hp but our 307 got more advance and was rated for super fuel), so give it the 4BBL carb/manifold and you'd probably see it just about equal with the 308 in performance if both have the same style exhaust fitted. XT would probably be quicker than a HT-HG 308. HQ is lighter. I doubt an XT would outperform a a HJ 308 though.

Edit - I missed the bit about testing the cars. The thing is the press in general wouldn't have known. At the HK release, the whole testing process was extremely controlled. No-one drove the GTS327 without having a GMH staffer in the car, and they were not allowed to rev the engine over the red line on the tacho, which was fixed at 5500 for the 6cyl engines. A few weren't fooled including Rob Luck wasn't fooled enough to believe the scam, and he got hold of a private car to test. Read Racing Car News from September 1968, 0-100mph in 19.8s and 15.4s@92mph over the 1/4.
For HT-HQ 350 manual cars it was simply a matter of a minor fiddle with the Quadrajet to slow the cars down, and it appears the same was done for HJ 308 manual. The road testers of the HT-HG GTS350's wouldn't have known either, and the auto cars they got to test were fitted with power robbing accessories and tall diffs. Again Rob Luck in 9/69 RCN tested a GTS350 manual, this time a GMH supplied car but fiddled with. It is obvious from the times obtained of 0-100mph in 18.9s and 15.6s@92mph that the car wasn't in proper tune, there is no way a stock HT GTS350 is slower than a stock GTS327. You will not find a comparative road test done on one of these cars tuned to factory specs until the AMC article from a few years back. Again the tests done on new cars in 1969 were all done with a GMH staffer in the car.
It wasn't until HQ where the engines were identical and the diff ratios were identical for manual and auto 350 that the fiddling with the manual engine's carb came into light. Read Sports Car World from 7/72, the auto was 3 seconds quicker 0-100mph than the manual, and these weren't the only testers of the day to get similar results. They clocked 0-100mph in 19.8 seconds and 15.8s@87mph over the quarter for the auto. They even reported that they were puzzled, but the figures they obtained for the manual car were on par with the figures obtained by Wheels and Modern Motor on different GTS350 manual cars.
This is all historical fact, remember GM were not involved in racing and they had to be as quiet as possible with any furore over them building race cars. If need be you can even find good 1/4 mile data for properly tuned cars with no mods other than the exhaust being removed. Dave Bennett took his 9 day old GTS327 with 3.36:1 rear axle down the quarter at Calder. Its only mod was the exhaust was dropped and it did a 14.46 running the factory D70 tyres. There was a similar test done of one of the series production (PhaseII I think) Falcons done in 1970-1971, it was essentially a stock but properly tuned road car with free exhaust past the first join - this is where the 14.1sec time often claimed comes from.

Edited by user Thursday, 11 February 2016 9:15:36 AM(UTC)  | Reason: Added info.

Weren't the Email and Carter Carbs the same basic thing? Some Fords had the same basic carby as well.

I wonder if the Carter was a bigger CFM than the Stromberg on the 253, if so she may of had a bit more power.
The reason for the Carter ? Stromberg did not get it's act together in time, so the Carter was used ?

I think it was just alternate supplier, like Lucas and Bosch dizzys and alternators. The first of the 253's in HT had WW Stombergs from memory, it wasn't until the 70's that some 253's got Carter carbies - I can't remember for certain when the Carter/Email carby was used on the 253 but it may be as you state, ie the WW's weren't ready for a canister in January 1975 (sealed fuel bowl) but Email was? Dr Terry might know more.

I think the intake manifold holes to the carby were the same as the WW2 Stromberg and I know that the Carter do make a lot of different size CFM, so it would have to be around the same size.

The slant 6 could be had with the 2 Barrel Carer as was the 245 and 265 Hemi, not sure of the CFM of any of them that they had and their was the XB Falcon 302 and 351 that got the same type of Carter but as for CFM I don't know, but I think they were the same size CFM for both.

The Leyland P76 I seen one yesterday a 6 cyl with the original number plates and all a real old dude was driving it up at Kilcoy, I could not believe it.

I've never seen one either, only know about them from service manuals. Every 253/4.2L engine or car I've ever bought has had a WW as you state.

The Ford figures aren't when you look at what they quote for GT-HO vs GT. I don't love the old gross figures, they are simply the only figures you can use when comparing engines. Net figures are useless once you put different transmissions, exhausts etc into the equation. Figures even get quoted at different rpm for manual vs auto transmissions which is totally useless, just look at the net figures for the 1972 L48: 210hp@4400rpm, 300lbft@2800rpm for the manual and 175hp@4000rpm, 290lbft@2400rpm for the auto. They are the same 270hp gross engine, 270hp@4800rpm, 360lbft@3200rpm.

Aussie Chev (or Chev design in the case of the Canadian engines) are identical to what was in the respective US or Canadian vehicles depending upon whether the engine was Tonawanda or McKinnon sourced. They are the identical engines used in the USA other than for the distributors, and of course the sumps in HK-HG Holden. The GTS327 Tonawanda engine even uses the same distributor as the US 1968 L73 engine that it is. The revised distributor and initial timing will be because the fuel octane here was higher than what these engines were designed for in the USA other than for the HT-HG GTS350 manual engine, however the HK's distributor on these engines is essentially the same end settings as what the US engine got. Some of them got a different carby number to what was used in the USA (late HK with Canadian engine to 1972 HQ) as they got numbers specific to GMH however the carby tune was identical to the same engine in the USA, with the exception of 1973-1974 HQ 350 engines - these got the carby off the 1972 US L48 probably as after 1972 the US carbies were tuned for ULP.

I just found the cam data.

HT-HQ 253 and 308 both use the same cam 7434871. HJ 4.2L uses the same cam. ADR27A HJ (and I assume HX) uses 9936253 and HZ changes to another cam with an M number, M38192. Blue 4.2L uses 92000944. This is from parts catalogues so can be deceiving sometimes.
HJ-WB 308 and VK-VL standard carbied 304 engines use 2825882.

7434871 specs are:
Excluding Ramps: inlet 27/63-270, exhaust 71/19-270, 46 overlap.
Including Ramps: inlet 43/91-314, exhaust 87/47-314, 90 overlap.

2825882 specs are:
Excluding Ramps: inlet 29/71-280, exhaust 79/29-288, 58 overlap. (shown for HX-HZ as 28/72-280, 78/30-288, so shown 1 deg advanced in HJ).
Including Ramps: inlet 39/91-310, exhaust 89/51-320, 90 overlap. (shown for HX-HZ as 38/92-310, 88/52-320,so shown 1 deg advanced in HJ).

You may recognise 2825882 as the same cam as the Chevrolet general performance hydraulic camshaft that was used in HK, HT and HQ engines.

HX emissions cam I assume to be 9936253 is:
Excluding Ramps: inlet 8/42-230, exhaust 15/15-210, 23 overlap.
Including Ramps: inlet 30/78-288, exhaust 47/51-288, 81 overlap.

The emissions cam listed for later 4.2L HZ, I assume this is the M38192 part number:
Excluding Ramps: inlet 14/60-254, exhaust 42/32-254, 46 overlap.
Including Ramps: inlet 32/80-298, exhaust 60/58-298, 90 overlap.


I thought the excl. ramps figures were 6 thou lift for all GM engines, but I can't find where I read that.

The above does show that GMH used a more aggressive camshaft in 308 from HJ, probably to take advantage of the extra compression.