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Originally Posted by: HK1837  Originally Posted by: castellan Originally Posted by: HK1837 Originally Posted by: castellan Originally Posted by: HK1837 Originally Posted by: castellan Originally Posted by: HK1837 ADR27 stuff came in in September 1972 but Ford and Chrysler got an exemption until I think 1/73. Will confirm later.
ADR27 didn't affect performance, just idle mixture.
HJ 5.0L is more powerful, there is no argument, they simply are.
Gross hp figures are the ONLY reliable source of comparison, net is rubbish.
GMH had a habit of disguising the performance of their top spec manual cars. They did it for HK, HT, HG, HQ and even HJ. Some cars got reported correctly but most that were allowed out to the press were hobbled. Try and find a road test for an LH SLR5000 with a HJ engine, even an early LX. These were quicker over the 1/4 and higher trap speed than an L34. Rob Luck did a road test on a private GTS327, Mel Nichols got a properly tuned HT GTS350 and later Robbo did too. HQ GT350 manual was never properly tested in real tune, only the auto was, reporters even stated that they were scratching their heads why the auto was over 3 seconds faster 0-100mph. Even the press test HJ 5.0L manual HJ GTS was fiddled with. The only place you'll find the true performance figures on a manual HT-HG GTS350 was on the unopened HG in AMC a few years back - the car had never even had a clutch change until a few years after the article.
In the end you need to ignore the 1/4 mile tests but look at the trap speed at the end of the quarter. This will give you the true performance potential as it takes out wheelspin. If you can see if you can find Rob Luck's road test on the HK GTS327, compare its mph at the end of the 1/4 to what AMC got for the HG GTS350 and original tests of the Phase II and III. You can see the slight increases in mph between them. All interesting stuff. 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. The Ford figures are a total fact of reality, look here a 1975 Falcon 302 V8 and the F100 302 V8 ? By your beloved Gross system I would not know bugger all that their was a difference in the engines at all, but the fact is their is a few differences and Net figures prove something is up ? Now the XB sedan 302 has a 2 Barrel carter on it but the 302 F100 has a Stromberg on it and then as time goes on she gets a Carter 2 Barrel and then a 4 Barrel and all are quoted with their Net power ratings. My mates old man had a 1977 F100 with the 302 V8 and it was gutless as, my old man had a 6 cyl 250 F100 and she was impressive for a 250, my dad said he test drove 3 F100 with 302 V8's and said they had no guts, so he bought the little 250 6 cyl, now I thought he was talking B/S at the time, but then we pulled the 302 of my mates F100 down and found this pissy little Stromberg and a intake manifold that had cone shaped holes where the carby bolts on to it, the bastard cones down to smaller than the Stromberg throttle body flaps to about the size of a 10c piece, no joke ! I know when talking about old chev engines that one has to talk in the old gross figures to get a handle on what is what, sort of. but as we se the chev engines we got in the Aussie GM-H cars do not always add up to what the Canada or USA cars truly had. 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. Holden never had such a powerful up grade as a GT-HO P2 P3 such a engine V8 chev powered Holden's are only in the GT 4V 351 performance class, never in the GT-HO class. The 1972 L48 HQ 350 manual is most likely for a twin exhaust and you will find the other is for the single exhaust. you are reading from the USA figures ? Australia did not have higher octane than the USA in 1968 I am sure of that, now remembering that the USA octane rating is not the same as our RON as the USA use the MON rating. The tune of the carby on the 1973-4 350 could be jetted some what like our ADR27A gutless rubbish was. Remember the HX 5.0L manual does not have EGR ? so one has to wonder, it must of been the jetting as to why the loss of power, that has to be the only reason. The last 327 was not like any other in the USA or Canada car powered engine I don't think. The Last of the HG 350 was not the same as any USA or Canada Car powered engine I don't think. The 350 HQ were the same as the USA car engine. An unhobbled HT-HG GTS350 manual is not far behind a Phase II or Phase III in 1/4 mile times. Look at the respective mph too. The GT-HO's would beat it every time, but you'd have to be a good stick shift operator! Those are USA figures I quoted. The ratings are at different rpm, not with different exhausts. Yes we did, Australian Super fuel was around 97-98 Octane, US was higher for Premium but our Standard fuel was lower than US Regular, hence the engines we got here that were designed for US Regular had to run on Super, hence why GMH gave the engines more advance. The 7042202 carby on our 1973-4 HQ engines was pretty much the same as the earlier ones, just a bit leaner idle I think. No manual HX-VK 308/304 has EGR IIC. The loss in driveability for HX 308 is the inlet manifold and the loss of 4deg dizzy advance (I think HX went back to the HT-HQ 308 max advance). There could be some carby adjustments too, but don't think it was that bad. Remember once GMH got their act together the blue and black 308's went pretty well, the main difference being the manifold and they actually lost compression. The rest of the engine is pretty much the same and complied with the same emissions or higher. Correct, the final versions of the HK and HG engines were specials, but only because neither was in production in the USA or Canada anymore - they were simply over-run and small quantity though. The original engines in both Series were the same as US engines (bar the distributor for the HT). The early HQ 350 engines were the same as the US engines, but again the dizzy was different - these used the HK's distributor. Our 1972 engines were essentially the same as the 1971 engines, and the HQ 1973-4 engines were pretty much the US 1972 engine (used the 1972 carby and manual L48 dizzy). No the HX intake does not restrict the stock 308 at all, you know why I know that for a fact is because I used one on a pre ADR heads 308 with it in stock form and with a 20/60 cam with stage 3 heads, I had some toe rag jet it lean and that was the biggest killer of performance that I came across, it was a gutless bag of s--t that used more fuel then ever before and after all the work I had done to make it perform, it had less power than the std engine I had before, so I know what is and what is not, I said listen c--- to this Dyno tune carby clinic low life, this is the jetting air fuel ratio that needs to be done to make it perform, No way would this clown do it, his reasoning was that I could not afford the fuel it would use ? now I had the car for 5 years or so and could get 22MPG on the highway but after this turd I got 16 to 16.5 MPG but the clown had destroyed my vacuum advance as well, in spite I would say because the problems started the day he ginned around with it. That was the day that I never let any prick touch my car again without myself informing them what to do. They f everything because they are morons that don't know jack mainly, sure they will tell you all the B/S under the sun to sell you shit you don't need. I have had to argue with such morons even with brake pads, I said I don't give a toss about the cost I want the best, but no they wanted to use crappy cheap pads and I said no way in the world would I use grand mother brake pads, as I informed them I drove flat out over 200KM/H plus like nearly everyday. They would just reject what I was saying to them, Just because I look like a Priest to them maybe  . I drive 50,000KM a year so over time I have learnt what is and is not, than to have same piss ant try to piss in my ear. Look the best performance is in the jetting and the exhaust tune without this, all you do is mainly worthless. get this and your away getting value for what you have done to the money spent on the engine. Look the fact is a GT-HO P2 P3 has a 40/80 cam and that's a bloody big cam, all Holden chev engines had a shitty little std cam under 20/60 in reality and the fact is they do not make the power of a GT-HO P2 P3 at all and 1/4 mile times are shit, try 1000m that's where you will see the GT-HO P2 P3 kill any Monaro for dead, The first Windsor powered GT-HO is a worthy car that will even still eat any Monaro on the highway, and i don't say that because i am a Ford man, because i am not, i am a Holden man mainly, but not one eyed about it, I will bag Fords at the drop of a hat to if they deserve it as well. The worst thing one can do on a road driven car is to go to big with your intake manifold and looking for the max power that an engine makes is not the bees knees at all, only a wood duck believes crap like that and sure the 40/80 cam in the HO's is a bastard to drive and sure the small cam in the chevs have their advantages on the 1/4 and on the track etc. I spent many a nights out dragging other cars to know what was what and the HX intake was sure not a disadvantage at all.
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