Rod length on A14's and A15s is 133mm centre to centre +/- 0.05mm.

Watch your compression on the smaller a12 chambers. You can actually go for quite a big cam with an a15 and still achieve 0.060" clearance between piston and valves.

I have a simulator which can give very accurate results with all this type of thing. Its very useful in designing engines. When you have a good idea of what you are planning to do, then I'm only too happy to run your specs through it.

Things I'll need to know are bore, piston brand and type, cam specs (or let me figure out the biggest), chamber volume and depth the valves sit above the head/gasket interface. If you give me head flow figures, inlet manifold dimenions, header dimensions as well then I can also give you a rough idea of flywheel HP.

Daniel