You can't really compare many of those engines as the ratings are all over the place, some are SE gross, some are net. It gets really painful to try and figure some of it out.

The 307 was never meant to be a performance engine. When it was introduced in about August 1967 it replaced the 283 which was only a 2BBL low comp engine by that stage. At the same time GM had:

307 2BBL 200hp (69-70cc heads. Code L14).
327 2BBL 210hp (standard V8 Camaro engine 75cc heads. Code LF7).
327 4BBL 250hp (standard 4BBL V8 in full size, what we got here in 1968 Impala and Parisienne and GTS327, same heads as 307, Code L73).
327 4BBL 275hp (same engine as 250hp but with 291 or 040 fuelie heads. Code L30).
350 4BBL 295hp (L48 engine, 1968 version of the HT GTS350 engine, same engine as L30 but 3.48" stroke rather than 3.25").

There were the high performance 302 (Z28) and 327 (L79) as well but that was it.

The 307 eventually replaced the 210hp 327 in Camaro as the standard V8 late in 1968, a few months into 1969 model year. This was a 1969 307 though so it had different heads to the HK 307 and the block was revised a bit too.

So all GMH did was use the 307 as GM intended, as a 2BBL base spec V8 engine. The only reason they used it was the planned 283 was cancelled before HK release. There have been GMH documents found with a code for a 4BBL 307 but no such thing was ever made by GM as a regular production engine. The 327 as used by GMH in the GTS327 was simply the next engine up and the logical choice as there would have been little point in a 2BBL 327, it really made no more power than the 307 already used in HK. Remember GMH rated the 307 at 210hp and probably rightly so as it had more timing than the US 307 and was to be run on Super fuel. It was also 8.75:1 compression, the 2BBL 327 was about 8.5:1 courtesy of its 75cc heads although it did get a compression bump for 1969 model year to 9:1 as the heads were switched to the same specification heads (69-70cc) as the 307 and the 4BBL 250hp 327.

Having said all that a 307 dressed with a 4BBL 327 intake and carby goes pretty well given a dual exhaust. It was a pretty common mod in the day. The HK 307 in that form is identical to a GTS327 engine other than the 1/8" bore difference. Same heads, same cam, same dizzy, same exhaust manifolds, same crank and rods. All you'd see is a few less hp due to the 20ci difference, plus the 307 loses 0.25:1 or so in compression due to the slightly less swept volume of the piston. Many people bored them straight to 4" at rebuild anyway, and then they are identical to the 327 at that stage, although I couldn't count on my fingers how many I've found also sporting 350 crankshafts too. I have one in my shed that was running at +4.030 for long enough to make a lip, and I had one in my FJ40 'cruiser at 4", plus my mate's HK 307 was out to 4.040" pulling 450hp for over 20 years until a rod bolt let go.

Back to the original question. I believe the 340 was a serious weapon. I also believe Valiant imported the 300 odd motors in 69 to satisfy the minimum build numbers required. I think it is settled history that they used the test ute mule, shortened to charger wheelbase (before charger release) to track test 340 v triple carb 265 at Malalla. 265 was 3 seconds faster, generally put down to handled better with less weight. Many have speculated that on an open track like bathurst 340 would have had advantage. Anyway, much like holden had to clear out 307 after HK, valiant did the same with 340 in the e55. Pity it was auto only, that really would have killed it for any true drivers in the day. BTW, valiant didn't actually offer ANY v8 with manual. You couldn't get one at all (until 77/78 in panelvan and limited chargers (80 I think)

Old Man Emu would have been a weapon with a 360-370hp LT1, Muncie and 12 bolt posi. Brakes were obviously an issue but they were working on the failed oil cooled idea. The other interesting thing to ponder is at least by mid 1968 GMH had probably a 75% HQ design which they would have known would be using HK stub axles on HQ. And as we all know because of this HQ rotors and calipers bolt straight onto HK-HG. I’m pretty sure some South African assembled HK-HQ had Chevrolet stud pattern, but in any case the rears were not hard to change. And they had easy access to 4.75” PCD wheels from GM. So if the will was there they could have had better brakes on such a car if they needed to. But in the end I think reality told them that to get high power production (read cheaper) engines with specs good enough to race, ready to go out of the USA after 1970 they’d have to do what Ford did and change engines here themselves. Remember from the start of 1971 model year (9/70, meaning engines produced starting late July 1970) Chevrolet engines went soft, and just to finish HG GMH had to have the Canadian St Catharines plant specially build them some 1970 spec L48 engines, which would have been more expensive as they were no longer produced. One possible option was the HG 308 GTS with tall rear axle to keep the 308’s rpm down. But the cheaper option as it used far less imported parts was the LC Torana. Sure it had a set of imported carbs but in reality it was simply a GTR with a production 186S with 161 head with a bit of extra $ in the outsourced head work and a different cam. Sure the car had a few low volume specialty parts but still a far better bang for buck overall, even if doing it let Ford dominate the big race for a few years. And GMH could control their own components rather than get stuck with forever evolving US engines and driveline components. And at this time LH with the local V8 would be very much common knowledge too.

Yes, English Zenith-Stromberg.

Dr Terry

The problem is that everybody loosely refers to all these as being "Strombergs".

The early cars (FX-FJ) had US made Stromberg downdraught carbies.

FE to HZ had Aussie made Bendix-Stromberg downdraughts.

The CD side draught carbies were UK made Zenith-Strombergs, a very distant relative, with no design features in common at all.

Dr Terry

Edited by user Thursday, 24 October 2019 8:54:59 AM(UTC)  | Reason: Not specified

Gross Hp is the only way to compare engines, not sure how many times I have to say it! Net introduces variables that confuse you, sometimes they are with auto box, sometimes manual, some with single exhaust, some with dual. It gets too confusing.

No they aren’t. 307 dressed the same as a 250hp 327 still goes well, there isn’t that much between them. You’ll notice the 20ci but nowhere near as much as 161 to 186.

HK GTS327 and the Impala/Parisienne were just over 9:1, same as auto HT engine. HT manual was a Mickey over 10:1. GM always rounded up to the nearest 0.25:1. The 275hp 1968 327 was 9.8:1 but rated at 10:1. You can work all these out by the GM published figures. The final GTS327 were about 8.55:1, same as the 1966-7 GMH assembled Impala and also the base 210hp 2BBL 327 in ‘67-‘68 Camaro.

All the high compression Holden engines from EH onwards ran on Super as far as I know. Same with 253 and 308 which were both 9.0:1. You could buy low comp versions of all of them except 308 with compression ratios around the 8:1 mark give or take a few points, to run on standard fuel. They just stuck 179/186 heads on 149 and 161 to drop the compression but with 173 they also dished the piston as they would have gone above 8.3:1 which was about the limit for Aussie standard fuel on these engines. The 8.75:1 307 and 9:1 327 were right there in the desired compression range for Super fuel. It was only the HT-HG manual 350 and a little later the XU1 that went up significantly over 9:1. The HQ 202 was 9.4:1. They didn’t bump the 308 to close to 10:1 until mid 1974 on the L34 (9.8:1) and a few months later on HJ 5.0L (9.7). 253 had to wait until HX to get 9.4:1.

Fact is that only 124 VH E55 were made and only 212 VJ E55 were made that's 336 I would say and the VJ 340 V8 engine is not the same as the VH for a start.

I was looking into that last night with eng numbers and build dates in VH E55, eng no 00001 in the last cars was built on the last day of E55 built 1/6/1973. now the VJ model started coming out in Apr73.

But like the Falcon GT from Sep 1973 say Then we start getting the more ADR stuff coming on, so the carbys would change about this time in the VJ E55 I would think.

One dude claiming a steel crank in a 11/9/73 car and AVS carby with D01123 eng no. orange paint under the blue and large valves.

One dude claiming a steel crank in a 16/11/73 D00151 eng no, J heads but small valves and AVS carby and correct intake manifold for that.

Now I would think that when Valiant Aus got the engines imported in they went about stamping Their numbers on them and then stacked them away and out came a eng of that stack pile regardless into a car for the cars up to around Sep 73 build, some AVS could of slipped through like the 16/11/73 one, but she has small valves.

So I see that the 1st E55 is 1/9/1972 and goes to Dealer W868 West Aust I would think the W stands for and Dealer 868 their, now maybe that was truly the first order or is it truly the build date. the care was lime in colour.

Then the 2ed is lime 4/9/72 N755 Dealer NSW I would think.

3rd and 4th is red and a lime one both 7/9/72 to dealer F100, what F means I do not know, but it's funny that the 2 cars must be ordered on the same day I would think.

The highest eng no in the E55 VH is A00158 and went into a 19/1/73 car.

So one could say that their were 158 engines built with A at the start, maybe that is the 1st batch imported ? and the eng no starting with D could be a bitsa with some steel cranks ect.