I also meant to mention, imagine the LJ GTR and to a lesser extent the LH SL/R with a 3300S rather than a stock small cam 135hp 3300. One of the magazines of the day speculated what GMH were doing (prior to XU1 release) and stuck a 145hp 186S into an LC GTR, it was very quick. Imagine this as a 3300S with another 15hp or so (assuming a 202S would get the 186S cam). The LH Gpack with its 3.36 rear axle would have been quick too. Neither of them XU1 quick but still would have been far better car than the stock 3300 cars.

I agree that the 308 with the 2BBL will be OK. It will lose power (as you witnessed) but will have good low end torque. I had a 307 in an FJ40 that was pretty much stock except it was bored to 4" (327ci) and had a 500 Holley 2BBL on it. Was awful. I pulled the 2BBL off and put a 4BBL manifold and 600 vac sec 4BBL Holley on it. Went well with heaps more power but didn't have the low end torque needed. In the end I put an original 307 manifold and 2BBL Rochester on it, was brilliant. When I converted my Nissan Patrol MQ ute to a 302 SBC and TH400 I fitted a WW Stromberg 2BBL initially, but it wasn't good. I actually fitted a 4BBL intake and a VK Quadrajet, was perfect, had low end grunt and revved out well with good power production. So when you put a Quadrajet on a 253, and set it up like GMH did for the VC/WB they do go really well. A 308's Quadrajet isn't setup right for a 253. Thebest 253 I ever drove was a sweet little motor. Nothing special, was a later one (HZ/VB) with the dome top (9.4:1) pistons. It was fitted with earlier HQ heads and 308 intake with a blue 4.2L Quadrajet. It had HEI ignition, extractors and a single system, and was fitted with the better HJ onwards 308 cam. It was a 5spd manual with a 3.55 rear end. Was a sweet car to drive. Engine was nothing special, but was just right for a daily driver.

A 202S would go better with big valves, but GMH would never have done that in 1970 era. They were a big volume auto producer, just like GM. They built stuff to be used wherever practical across the board. Remember GMH had Perfectune do the XU1 and L34 heads, they didn't do it in house. Pretty much the same for the bigger cams done for race teams to fit themselves, they were done by outside suppliers. As it was a 186S had 145hp, that is 15hp more than a stock HT 186 from the identical engine specs bar induction, headers and timing (HT onwards 186 used the 186S cam in most applications, earlier HK and HR 186 had a smaller cam and was 19hp less than the 186S). All GMH would have done with the 202S was to fit the same stuff the 186S had: better bearings, valves and springs, the induction and headers. Using the same % gain for the 186S over the 186 (same cam between them) this would put the 202S at 151hp (stock HQ 202 was 135hp). It'd probably have been actually higher with the 186S cam, the stock HQ 202 cam was the original 161 cam: 35/75 70/40. The 186S was 43/85 95/48 (these are both including ramps, but you can see the comparison). So if a stock 202 went from 135hp to 151hp with the small 161 cam, with a 186S cam it might have seen 160hp. Add big valves and porting maybe closer to 165-170hp. Getting way too close to the claimed 185hp 253 and thus the HQ GTS would have made a HQ V8 GTS manual with single exhaust and 3.08 rear axle feel slow compared with the GTS's 202S with the same ratio aussie 4spd and a 3.55 rear axle. Plus the 202 would be less restricted with the single exhaust than the 253.

Mick is right about modern technology especially cams. GMH did exactly what GM did with cams, just had a handful and used them across the board. For the later 60's and 70's GM only had 3 production SBC cams, two hydraulics and a solid. The one hydraulic cam was used from 8:1 truck engines through to 10.25:1 300hp 350, this was the same grind as the HJ-VL 308/304. Their next hydraulic was used in the L79 327 350hp (Corvette, was 325hp in others) and 350hp 350 in Corvette. The solid (Duntov cam) was used in the 365hp L76 327, 375hp L84 327 and in Z28 302 plus the 1970 LT1 360hp/370hp engine. As I said, GMH did the same, they developed a better cam for the 308 right at the start (the HJ onwards 308 cam) but saved their pennies and used the 253's cam and retarded it, this was simply done to reduce costs and to have one less part. When they wanted more power they stuck the other cam in and it stayed there on all production GMH 308/304 vehicles until the end of VL (Group A engines excluded). Today with modern roller cams, you can wring huge increases over flat tappet cams especially hydraulics. Modern head chamber designs (plus modern porting practices) also make a huge difference. A simple look at the power output from stock alloy LT1 Corvette heads from the 80's or stock cast 350 Vortec heads compared to the old big port, closed chamber, big valve fuelies of the 60's shows you that the newer heads function far better than the old ones. EFI 304 heads compared to the older heads especially with the 5.7L/350ci versions is another example. Look at LS engines, they are a simple old fashioned pushrod engine, that will outperform old 350ci and 377ci engines with factory componentry, it is all in the heads and roller cam. Put modern alloys and a roller cam on an old rebuilt 350 and it'll perform just as well. I bet those Commodore Cup 253 engines have some hard work gone into their cam designs! If you read the last bit of this article, it shows what they got out of a repro L84 by simply using a modern cam grind versus the original solid cam:

http://www.superchevy.co...ie-motor-on-engine-dyno/

That 308 HQ has the 253 intake on as well as the Stromberg.

Your 307 chev Stromberg carby ? they are not the same as the Holden one ?

I wonder why they used that Rochester carb on the Bedford low comp 308, from what I can figure is that that carby is a 352CFM.

The 2V Stromberg is 320 CFM, did they use this carby on the 253 Bedford.

The 202S was made. According to GMH the GTR XU1 has 3310'S' engine as Standard fitment.

I'll disagree. It is a 3310'S' engine. I have not found any GMH documentation stating the LJ XU1 engine is classified as a 202X or 3300X engine.
The breakdown of the 'LJ XU1 Performance Package' states the package includes the 3310'S' engine, M20 4spd transmission, N66 Rally wheels and G80 LSD.
As you said, a 202S in HQ Coupe was canned before production commenced (early 1971), so it's not like 202S or 3310S was already in use like 186S was when the LC XU1 was released.
GMH made the cars so they chose what they chose to call/classify their cars or components thereof.

I found some interesting 'S' engine stuff over the last few days.

The initial LC Engineering Technical Specifications document and subsequent updates call the 2600S a 161S. The supplement for 1600 and 2850 engines calls the GTR engine a 173S. The XU1 supplement just calls the LC XU1 engine "XU1", but I did find some LJ release documents that call the LC version of the XU1 a 186 XU1, but it also called the LJ engine 202ci then qualified as 3300 XU1 (the normal GTR engine is listed as 202ci and then 3300 HC). The LJ Engineering Technical Specifications initially call the LJ XU1 a 202 XU1, but this is later revised to 3300 XU1.

I did find some really early LJ planning paperwork with the LJ XU1 engine as a 202 's' (exactly as typed). The first draft list for LJ Press test vehicles has the XU1's requested also as 202 's'. But there was a lot of early stuff for LJ XU1 I also found that was not how they ended up, like the early documents show the LJ XU1 was supposed to get an M21 box (1.38:1 3rd), but it was revised later before release to the XU1 M20 as we know it (with 1.25:1 3rd). There is a lot of stuff like this in the early documents that were changed.

I found documents showing the HQ GTS coupe was canned early December 1970. At this time they were changing the planned Press Test 80737's out for 80837's. Most of the correspondence is 3-4/12/70.

The most interesting document though is a HD one. Dated 8/64 there was a revision where the 179S engine name was changed to X2.

It is the big ports on those engines not the roller cams that kill low end torque. If you took a stock HT L48 350 and put a roller cam in it with appropriate springs it will outperform the hydraulic cammed engine across the board. Same with a HQ 308. LS engines and EFI 5.0L have ports really too big for the engine’s capacity and designed use.