I can't help you with the flow figures for the different generations of red-blue-black 6 heads. However GMH would never have built a far better 202 for a Holden as it would have been too close to a 253 in performance. I'm almost certain the reason the HQ GTS was cancelled was a 202S would have performed that close to a 253 at a far lower price. They in fact waited until the 253/4.2 was cancelled to build the fuel injected 3.3 in VK.
If you compare the two dead standard HT GTS models it is quite clear. Remember this is a 186S, M20 and 3.36 rear axle versus 253, M21 and 3.08 rear axle:
First figure is the GTS, second figure is the V8 GTS. The 6cyl car is actually a HK GTS (but essentially the same thing) from Motor Manual 10/68. The V8 GTS is Modern Motor and Wheels both from August 1969.
0-30mph 3.5s, 3.6s
0-40mph 6.2s, 5.1s
0-50mph 8.3s, 7.7s
0-60mph 11.5s, 10.2s
0-70mph 15.7s, 13.6s
0-80mph 20.3s, 18.5s
0-90mph NTR, 29.0s
Top speed 102mph, 111.2mph
Standing 1/4 18.3, 17.6
Economy for the test 21mpg, 22mpg
Cost $3007, $3423.
So step forward a few years, the HQ V8 GTS remains pretty much unchanged performance wise, same 253, now an M20 Aussie 4spd and still a 3.08 rear axle. The HQ GTS however would have had an extra 16ci and another (estimate) 25hp courtesy of a 202 with the S camshaft, intake, carb and exhaust headers and the V8 exhaust. The stock 202 with 161 camshaft and standard intake and exhaust manifold was rated at 135hp, the 253 at 185hp (this is without exhaust), so the 202S would be exactly half way between the HQ 202 and the HQ 253 in hp.
So given a stock HK 186 is
[email protected] and
[email protected], this engine has a bigger camshaft than a HQ 202 but smaller than the S camshaft. The HK-HG 186S was
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[email protected], again this is an advertised figure but it is on a dyno. The in-car figure would favour the S engine even further as it used the V8 exhaust. If you consider the camshafts used (detailed below) you might even figure that the standard HK 186 might drop to below 120hp if it had the 161 (aka 202) camshaft fitted, so you might even estimate that the HQ 202S might have been advertised at 30hp more than the HQ 202 at 165hp.
161/202 camshaft:
15/45 50/10
186 (HK and trimatic HT-HG):
35/68 89/40
S camshaft:
43/85 95/48
Camshaft figures are 2thou I think and without ramps, but at least allow comparison.
Considering all that it becomes clear that a HQ 202S especially in a HQ GTS where it would have got a 3.36 rear axle (rather than 3.55) might have overshadowed the HQ V8 GTS and other HQ Holden V8 models other than the GTS350, noting I'm talking
standard models - all HQ Holden V8 standard models were 253 with single exhaust and either 3.08 or 2.78 rear axle, just forget the HQ SS for the sake of the argument (with its dual exhaust and 3.36 rear axle). Forget the 80260 as well - in any case it would be a 3.55 rear axle and if you could have optioned the 202S in an 80160 it'd probably have a 3.55 rear axle too.
Edited by user Saturday, 4 December 2021 12:14:24 PM(UTC)
| Reason: spelling