Originally Posted by: Blu253 
Originally Posted by: Smitty2 Originally Posted by: Sandaro I thought the 'plastic' tag came from the comparable light weight of the Holden V8 as opposed to the Chev V8 achieved in part through the use of alloy bolt ons including timing cover and intake.
nothing I saw or heard supports that... remember GMH released the 253 first (well before the 308) and
not a PROPER V8 was the talk on the street as it was vastly smaller that the littlest SBC in 283 form
and also the Ford offering. The XR GT of course getting a 289ci V8, a real V8 BIGGER than the 283 Chev offering
I guess I can see that on the 253. They are calling it a 6 alternative (which is pretty right) rather than a “real” V8 (which isn’t right).
I wonder if GM had disallowed the Aussie V8 but built the SBC here instead what we would have got? The 283 and 307 in place of the 253 & 308?
We were supposed to have a 283 for HK but the 307 replaced the 283 from September 1967 hence why the HK got the 307. Problem is both of those engines were only 2BBL past August 1966, the 283 was a 4BBL until the end of the Rochester 4G, they never made a Quadrajet 283 (Quadrajet 4GC replaced the 4G from August 1966).
The GMH V8 was meant to evolve in size over time like the "red" 6. It was supposed to start out small and not reach 308ci until the late 70's. Ford fitting the 302 into XT sort of killed all that off so it was made initially as 253ci and 308ci. As we know it eventually grew to 350ci late in its life.
The problem with the scenario question is the 307 was the smallest Chevrolet V8 from September 1967 and was the standard V8 in many car lines. The 2BBL 210hp 327 hung around until December 1968 as the standard V8 engine in Camaro (replaced by the 307 from January 1969) and the standard V8 in Chevrolet cars in 1969 was another 2BBL 327, same engine as Camaro but with the larger 2BBL making it a 235hp engine. The only 4BBL SBC available from September 1968 through to the 80's was the 350 (ignoring the one year or so that a 4BBL 400 SBC was made). GMH fitted the standard 4BBL L48 350 from the start of HT through to the end of HQ, they did use the short run low compression 350 (LM1) in auto HT and HG but it was a 4 month only engine in the USA (9/68 to 12/68).
GM did eventually make the 305 a 4BBL engine in the 80's.
There was also a 262 SBC in the mid 70's that was replaced by the 305 in 1977.
So if GM had said no to GMH, there could have been a few scenarios. Firstly the 250ci Chevy 6 was already being installed into HD-HR and later HK-HJ for South Africa. So that engine could have done the duty of the 253. Oldsmobile made the Rocket as a 2BBL 260ci engine from 1975. They also made a 307ci Rocket with Quadrajet from 1980. From 1968 they had a 350ci Rocket, in various forms. Pontiac had a 350ci V8 too. Neither of those Olds or Pontiac engines make sense though given the use of the 350 SBC, GMH would have wanted a 4BBL 5.0L engine from 1969. Pontiac did have a 326 but that ended in 1967, and they didn't have a 5.0L engine until the later 70's.
Buick had a 300ci V8 but it too was replaced by a 350ci engine in 1968. Buick also had the 3.7L 225ci V6 but they sold the tooling to Jeep and repalced that engine with the 250ci Chevy inline 6. They bought it back from AMC and in 1975 started building it as a 3.8L engine (we got this engine in VN). SO that wouldn't have been on GH's radar as GM didn't even make the engine in teh timeframe we are looking for. Same with the Chevrolet V6.
I guess the only other option for GMH for a 5.0L engine initially would have been to have special build 307's. It wouldn't be that hard, the auto 350 we got in HT-HG was just an L65 (large 2BBL 9.0:1 350) with the L48's intake and Quadrajet. Tonawanda built those for GMH after the LM1 ended prooduction in North America (12/68). Initially they'd have been special build bitzas though as McKinnon Industries that built the HK 307's didn't make 4BBL engines, that is why the last run of McKinnon 327's in HK had Tonawanda 4BBL intakes on them. Same with the 1967 Impalas and Parisiennes, they were bitza engines too put together by McKinnon. But those were all a lot lower volume build than what GMH would require to cover the volume of 5.0L engines. This would have been OK for the start of HT as the 1968-9 307 with a Quadrajet would have easily matched the HT 308 in power and torque. However after August 1970 all Chevrolet engines became unleaded spec, the L48 dropped from 10.25:1 (HT-HG 350) down to 8.5:1 (HQ 350). The 307 suffered similarly but not as bad, only went from 8.75:1 down to 8.5:1 and lost about 10hp rather than the 30hp of the 350, but it ended in 1973 meaning GMH would have been high and dry for a 5.0L V8 for LH Torana.
So the question remains unanswered I reckon the Chevy 250ci 6 would have been the answer for the 253 and there was a HO version available. The 5.0L engine, who knows?
Having said all that, IF GMH was to take an existing design and cast/build it here they could have gotten the Olds or Buick designs or a Chevrolet V8. If they built SBC here, the sizes that would have made sense would be the 283 and the 302. They would have shared a common crankshaft, and the 302 would have made a decent race option in Torana. They would have supplement these with an imported 350 for Statesman and GTS350. Possibly they'd have still used a 350 or 400 in HJ Caprice too if they'd had small blocks for lesser use bult locally. The 302 setup as per 1969 Z28 would have been far better than a 308 as a race engine. Potentially GMH could have just made the one head for both 283 and 302 (the 58-60cc power pack head, 1.72/1.5 valves with fuelie size ports), and built the 283 as a 2BBL only with the 302 as a 4BBL. The 283 would be about 9.4:1 and the 302 about 9.75:1 both with flat tops. Then use imported fuelies (as per HT-HG GTS350M) on the 302 and lumpy tops for a high output version.
Edited by user Thursday, 27 February 2025 9:45:02 AM(UTC)
| Reason: Not specified
