Hmmm ... a standard height A13 stroker engine. Good idea. The 1974 A13 used a standard A12 crank and the A14 bore size. But in a tall-deck block (same as A14). Yes you could create the same from an overbored A12 engine.

* For a high-revving performance engine, a big bore is more important than a longer stroke
* Better yet use the bore and the stroke of the A14: even better performance.

1200GX,

Possible food for thought, a stock A14 makes 10hp more than a stock A12. So using that as a guide a 1300cc motor would make 5hp more. Obviously this is rough math but given all the work why not do porting instead. I used ye ole dremel and some files to clean up the ports and gasket match. The valve seats actually protrude 1mm into the ports, just smoothing the seat so it mates with the port wall would up the power. I'm no tuning guru so I went slowly it took me two weekends, maybe 15hrs worth (I went slow), the result was an increase of 6+ mph at my local track or..........you can have racetech port it. Another plus is you would only have the head off the rest of the motor could stay intact.

As for the GX carbs, I happen to think they're a great way to go , especially for a street car. The only reason I'm taking them off my car is a I got a smoking deal on the Flat Slide carbs.

Tom

Thanks for the replies guys. I really need your inputs as I don't want to mess things up. I have now thought about going just one oversize to get the engine very close to 1200cc. That is what boofhead did as I am now really wondering if a 100cc will make a huge difference if I compare the trouble that I will have to go through to get it 1300cc with the possibility of someone making a mess with the con rod mods.
I want to get the WOW factor for the cc under the bonnet.

@rallytwit. We have a local guy here that I could hear over the phone is quite old.So I think he has quite allot of experience. He ports and gas flows cylinder heads and does most of the drag race guys's cylinder heads. I want to pack away my spare one in the cabinet and modify the one that is currently on the engine. I will explain to him exactly what I want and need. Most probably he will know what to do to a GX head not to mess it up and still keep reliable as I don't want to shorten (or anything like that) the valve guides.

@ racetech. Couriers will cost a arm and a leg.

100cc will make no difference. You won't be able to tell any performance difference.

That is what I thought as well when thinking about the 1300 or 1400cc conversion done to the A12. Too much stuff that the engineer shops can do wrong that needs to be modified for the cc increase versus the power increase it will yield.

Think I am going to stick to what boofhead did and just rebore to one oversize to make it a new bore as it has been honed before.

Another question. What makes the GX head gasket sold by Bprojects so special except the thickness? Is it also made of special material or can I ask a local gasket maker company (Like Payen) to make a thinner custom head gasket to the same specs as the Bprojects one.

Ah correction. I was wrong. A 100cc difference, from 1200cc to 1300cc will make a difference. Maybe 5 HP or about 8%. That is enough to tell. But not a huge difference.

What I was thinking of is simple oversize pistons won't make a difference. Do not waste your time boring for a 1mm oversize when the bore is fine. You can measure the bore to ensure it's still good -- with the A-series, a steet engine almost never need overboring due to engine wear. An engine that has been extensively raced will probably need it. If it needs then certainly do it.

The GX head gasket sold by Bprojects is a Nismo/Nissan Competition gasket and is identical to the original GX gasket. It is extra thin to achieve the compression ratio of 10.0:1.

Quote:
I do not recall how much the A12A rods cost,but it was not a prohibitive amount.
Quote:Well I hope I'm not dead yet.
In my personal view, the stock 1200 GX induction & exhaust will be very hard to beat when used in a street application.
I used mine for years & years & loved every moment of it.

I have a set of A12A rods on their way over from the states, for my Dodgeman Big cube conversion :)

the GX gaskets are Premium material and specifications, the Nismo composite gaskets are better again, one of our members has 180hp on Methanol naturally aspirated running the Nismo gasket..