IIRC that .039 gasket is around 8.8cc, so yes, compared to the .020 factory steel shim, is is costing you about 6/10th of a point of compression, and a V/P of 5 per the previous post.
Now, 5 doesn't sound like much, but from a V/P of 95 with that 8.6cc gasket to a V/P of 100 with the 2cc shim gasket, is 5% which, on an already low V/P, is a LOT!
I mean from 160 to 165 is relatively meaningless; Not so at 95
3.23s are about 10% better than than the 2.94s, not great but certainly one step closer. To be honest, If I had to buy them, I wouldn't bother.
Listen I'm not knocking your choice of engines, but this is a common shortcoming of this size of engine and only having 4 gears to work with; It just cannot do too many things at once. If it has to be mindful of hiway cruising, it needs to run those 2.94s or even less. But if you need more power and the engine is already built, then it really wants 3.91s, or more if it has a torque-hole. The only way around this is with an overdrive, and in your case, it would need to be, a 5-speed, NOT the superwide-ratio A833 3+1.
As luck would have it, your combo is a prime candidate for an AX15. The ratios are;
3.83-2.33-1.44-1.00-.79od compared to your commando at
3.09-1.92-1.40-1.00-xx
But it gets better; With your cam, you could gear the car to run 65=2000 rpm, which is gonna take a rear gear of surprise,
2.94s for 65= 2030.
and your starter gear would be
3.83 x 2.94= 11.26, which is 24% better than now.
Second gear would be 2.33 x 2.94= 6.85; I cannot tell you how perfect that would be.
Now, the splits are;
.61-.62-.69-.79 This at first glance looks a lil brutal in the first two shifts, but, don't overlook that, as a streeter, you are only concerned with the first one which is lower than it needs to be anyway, so yur never gonna feel that 400rpm hole in your powerband.
Finally, see how the splits converge at .69 and .79.. What this means is that as your speed increases, each shift keeps the engine closer to the power-peak, which means more average power delivered over time, thus reducing your acceleration times, say to pass. Currently, downshifting into third will get you 55mph@ 3000rpm, right smack in the hole of your powerband. well as it happens, third gear in the Commando is 1.40, and in the Ax is 1.44, so with the same rear gear, nothing changes.
But with a cruise rpm of just 2030(2.94s), there is nothing stopping you from running more rear gear, say up to 20% more, say you ran just 3.55s. Your cruise rpm would jump to 2450; then
While First gear would become a ridiculous parade gear of
3.55 x 3.83=13.60, while Second becomes
3.55 x 2.33= 8.27 a real ripper of a gear, but Third is
3.55 x 1.44= 5.11 compared to the current 4.12. So when you step out to pass at 55, the Rs will jump to 3780, right after the torque-peak and just getting up on the cam, so you'll be flying by every slowpoke you go hunting for, lol.
But Ok, I get that you got yur eye on a 3.23, so the road gears with those are
12.37-7.53-4.65-3.23-2.55; and 65=2230, about great! and that 7.53 Second is still pretty darn good and passing with 4.65s while not quite as exciting, is still not in the Powerband hole, meh just skirting it; with 55= 3440.
IMO, the Ax-15/3.83 low, with 3.23s could be your forever solution.
Adapters were still available a few years ago IIRC, so it's nearly a bolt-in.
Btw,
I have often thought about this combo, just not with your pressure "problem", which we have now got a work-around for. I would even try it with the current 2.94s ........ cuz you already got 'em, and cuz they're already installed. I'll tell ya, if I didn't think the world was about to explode, I would be on the hunt; I already have the engine, and the rear gears.
Here is a link;
The Novak Guide to the Aisin-Warner AX15 Transmission
www.novak-adapt.com
I'll get it back out and add the pic of the part #.
