a post from the past, but new to the forum, I was searching GT300 engine bay photos and saw your post and read them. I may be able to help some of you with in regards to information on the GT300/ST1/ST3 engines.
GT300 ran 95.5mm pistons,
Pistons pins were moved further up the pistons and there was virtually no skirt
147.6mm rod length, (titanium)
20mm pins but 3.59mm thick each side with a length of 52mm. (taper was 2mm to 3.6mm in the span of 10mm each side.
The heads were GT spec, ran titanium valves xeledyne? made in USA
They used special double valve springs, based on SR retainer, and special spring seats that varied from 1.5 to 3+mm,
lifters also were special and used various sizes from 34 to 35mm, and use SR20 shims,
Camshafts were low duration due to the 24.8mm restrictors, final spec was 268/12.3In and 266/12.0 ex and helped the engine make max power [email protected]
unrestricted they made 480hp on the engine dyne.
Throttle wise the first development was a 12 injector barrel throttle setup, which used a geared system.
in 07 they changed to a 12 injector butterfly setup, only 7 barrel and 4 butterfly were ever made.
Blocks had an integrated oil pump, which was geared. and highly technical.
Crankshaft weighed only 14.9~15.2kg. (Normal crank from Nismo weighed 18.9kg) it had 4 oil holes, on the journals, (I still have a crank) its incredible.
conrods weighed approx 410g
Pistons weighed 375 and 350g depending on spec.....
Compression was approx 14.0
ST1 (380RS engine used a special crank also)
ST3 ran VK45 titanium valves and VQ30DE lifters (solid) with Nismo valve springs
Hope that may have been interesting to some of you