I have a close ratio 4 speed for sale. not a cheep option tho.

I'm glad the gearbox issue was brought up. The stock 4 speed drops 3000 RPM's between 2nd and 3rd...........so I was always buzzing the motor to 7800 or more to cover the drop. An all out A12 race engine puts out 100hp at the wheels there about................I've heard 140HP at the flywheel for A12 and 170HP for the A14 so that is a pretty big gap. Keep in mind an A series race engine is going to be revved to 9000 RPM's and not likely make power below 5500. Finally is the rear axle an H145?..........it is going to have the same issue as the stock gearbox.

So if you're going all out use the A14 because you'll need a different gearbox (PJZ once told me that he could break the box simply aggressively shifting it, in other words you need to be nice to it) and a diff upgrade.

In my case I stuck with the A12 because that was what the class required but more importantly, I had tons of A12 stuff. The A12GX cost us $450, H145 LSD $250, the 4 speed C/R box was $500, cam & lightweight lifters $75 and the 39mm FCR carbs were $250....................all these parts were purchased from folks who had moved on to larger A series or other engine drivetrain combos. So if you can nab A12 stuff cheaply and the overall result is faster than spending the same $$$ to buy a stock A14, bigger gearbox and H150/190 rear end then go for it, if not then just start collecting the A14 bits over the next year or so.

My.02 Tom

It is a difficult one for me. The 5 speed gearbox is totally out of the question. They are plentyfull but really crazy in price. I can completely rebuild the A12 for the money the 5 speed cost here.
I still have the h145 diff aswell.

I am not the kind that does burnouts and drop the clutch hard. I do however want to take the car to the track one or 2 times when done to get the feel of it.
I can go A12 and then bike fuel injection or A14 worry about breaking gearbox and run SU's.
What do you think?

Newest update. I phoned a local car wrecker. The A14 sub assembly is the same price as a new set of lifters from Nissan. Can you believe that. I can just as well then for that price go A14.
This will include the following:
A14 block.
crank.
pistons and conrods.
No altenator.
No flywheel.
Flywheel not a prob as I am going to get my A12 one ligtened
Altenator can not be that expensive.
What worries me is the clutch. I think mine has a brand new A12 clutch on it. Will it handle the torque?
Will take my chance with the 56A and see what happens.
If the bore looks good I can just hone.