Dodgeman is correct about the race engines.
I think the race cams are .441 lift and something like 312 degrees of duration. The motor will not idle it won't come on the cam till round 5000 rpms and with a 9000+ redline they only go about 6 hrs between rebuilds.Also with 14-1 compression pump gas isn't an option. A12 race engine is about 140HP at the crank and I seem to recall 175HP for an A14.
I know the distributer will fit because I have an A14 electronic distributer in my A12GX.
We use the A14 valves in the GX head with the 120Y/B210 distributer, GX cam, header, 2 inch exhaust and cleaned up the ports. The motor pulls to 8K , idles well and runs all day long with no problems. The only thing I might change is getting something a little more aggressive than a GX cam as they are pretty mild.
The race engine parts even in the USA are pricey...........although keep your eye on E-bay becuase here in the states fewer and fewer modern racers are running A-series powered cars and only a small handful of cars have been left unmolested enough to switch to vintage.Also most vintage Datsun racers run 510's Z's and Roadsters. So for guys like you and I some really cool parts will be availible and decent prices for the next few years.

Tom

Thanks Guys

Seems factory racing specs are out of the question.

I totally understand that racing parts are no longer available, I have picked up that even stupid stuff for my A12 are starting to get scarce. Like my altenator. They are no longer available here in South Africa (the altenator sitting in the right bottom between the waterpipes).
That is also one of the reasons I want to go A14 and A14 5 speed. These stuff are still in production and parts are still readily available for them.
Although I think it will be cheaper to follow Dodgeman's procedure to get it close to 1300cc.
I don't mind boring the small end on the conrods. As mentioned I still have a spare complete GX engine. If they decide to fly through the block, so what.
The problem will be to find someone here on my side that can bore the small end perfect.
Will then give me a chance to rebuild the engine in every part so that it is nice and new again. Will of course do some mods here and there and a full balance job.
Rallytwit, thanks for the GX head info.
I would like to clean my ports aswell then and fit A15 size valves.

Dodgeman, that gearbox I have tried to find without success. But it does'nt stop me from still trying.
Thanks again for the info guys.

I don't know if we have the selection of heads the guys over in NZ and Aus have, but apparently one might end up with to high a compression ratio if you bore the A12 block for A14 pistons and fit the 1200 GX head back on. You just have to make sure that they don't skim the head if at all possible, then you might get away still. Otherwise you'll have to fit the A14 head as well.

Also, I know one or 2 people down in the Cape that would be able to bore the small-ends out perfectly. I sold the machines they do it with to them after all... Some people will actually try to hone them out to size, but the right way is to use a con-rod machine and machine them out with a tool. When I was an apprentice I did this myself, so I'll stand by and watch when they do it, to make sure the don't screw up.

If you want I can pick up a set on my way down in December, and have it done for you, most probably for free too...

The reason I have suggested using either the A12A or late A13 rods, or as an alternative, boring out late A12 rods is because these have more material at the little end. The factory made the rods that used the larger 19mm pin with more material for a reason I presume.

If you bore the earlier type of 1200/A12 rod, there will be less material around the pin to support it. Having said all that, I used bored out 1200 rods in my engine for many years without problems, but my engine never went over 5,500 rpm & was in a relatively modest state of tune.

So here's my recomendation. Try to find a late set of A12 rods, assuming that the A12 engine was used in the B310 models in South Africa. As I wrote, these seem to be the same forging as the rods with the bigger pins, but simply bored for the 17.5mm pins that the small bore engines used. Preferably the rods will be diamond bored to the finished size.

As for the compression ratio with the big bore, well I never had a problem & I installed a brand new 1200 GX head over a 76mm bore in my 1200 engine. Later on when the engine finally wore out, I bored to to the first oversize [76.5mm], overhauled the head, & stuck it back on. It ran on pump fuel & with the stock GX distributor, it never detonated as long as I used 'super' grade fuel [about 95 to 97 octane I think]

Too bloody easy mate.

Hi Dodgeman.
Will 120Y conrods not be ok?

I am a little worried about boring the little end of the conrod. I am planning to take my car to the track a couple of times when the engine has been properly done for the application. For 5500 to 6000rpm I think the boring of the conrod will be fine, but I plan to run 7000 maybe 7500rpm on the track and want to keep the Datsun name high. Don't want to go 2 laps and drop a conrod.
If I can get past my viance I must maybe consider A14 with GX goodies and 5 speed.

I have a set of 120Y GX con rods & they are the same as the 1200 rods that I have. This is why I suggest looking at some late ones.

The rod on the left is from a B210/120Y GX with the small pin & the one on the right is from an A12A. The rods are the same length. While I never had problems with mine, you can understand that boring the small pin hole out will reduce the material around the pin.
While I can't prove it, I believe that the late A12 rods are made from the beefier forging on the right.
The pistons are A15. A used original & a new 'replacement' in second oversize. [77mm] It was intended for my 1200 block.

Quote:

Which is why I suggested that he should not have the head skimmed if at all possible, to keep compression as low as possible, taking into account that we only have 93 at most pumps, and some 95 at a few very far between stations...

Point taken. Perhaps a head saver shim, a thick one, will help as his spare head has been shaved to the max permitted.

Quote:

Hahaaaaaaaaaaaa
Dodgeman, I can proudly say I have 2 spare GX cylinder heads. The one is shaved to the max which I plan to get rid of. The other one is 73.9mm thick and according to the cylinder head guy is within factory specs.
He said 73mm is the max skimmed thickness.
I am planning to use the one that is currently on my engine.
So actually I have 3 GX cylinder heads where one is currently in use on my GX engine.

Quote:You lucky SOB. Good fortune to you my friend.