To make a long story short a friend took his engine on a shop to rebuild it. The mechanic there supposed to overhaul it, put it on the car, did 500 meters or so and then a strange noises came!! Engine is opened and here we are. It is 126A5 from 500R, I took a look of it and I have a few questions since I want to help him locate all the needed spare parts he has to buy for proper repair. Is the Crankshaft same with the fiat 500 and fiat 126 or we have to find exactly the same type from a fiat 500R? We are looking for a good used one. Camshaft is also worn along with the crankcase which is going to be repaired with a new bushing, do you know the profile of this particular cam and since we are going to replace it can you suggest a faster profile for daily use since this is going to be pretty stock but if we can take a couple of horses why not? I noticed that the carburetor is 24 mm is this stock fiat 500R? I guess things will be much better with a 28 mm. The gearbox has the starter on the side as you can see on the picture, is this stock 500R gearbox or they have changed it with 126? Did the R had synchro gear box?