Hi Tom. Long ago I had a 1972 128 - yup 1116cc. Fond memories of that car.......
I am certainly no expert on the matter, but.....
Some things to keep in the back of your head if you are thinking of using X1/9 bits:
Firstly....no you cannot use any X1/9 tranny. As others have said, they are basically the same - BUT - the shift linkage comes out the BACK of an 128/Strada/Yugo tranny. On an X1/9 tranny the shift linkage comes out the FRONT of the tranny casing.
An important thing to always remember is that on 128/Strada/Yugo, the engine is mounted at a 20 degree forward tilt. On all X1/9s, the engine is mounted at only a 12 degree tilt. Whatever engine you install into your 128 will have to retain the 20 degree angle. This affects a few things if using an X1/9 sourced engine :
Firstly, thus an X1/9 oil pan would then sit not flat on the bottom. It has been done, but is not right. Easy solution is to just swap over the 128/strada/Yugo oil pan. You MUST then also use the oil pump pickup tube that goes with the pan you are installing. The oil pumps were all the same - the pickup tube is a separate piece that just bolts onto the oil pump.
Secondly, although the intake manifolds look quite similar between X1/9 and 128/Strada/Yugo.....in fact they are quite different due to the 20 degree/12 degree tilt difference. So...an X1/9 intake manifold will result in the carb/air cleaner no longer sitting horizontal in your 128. Maybe no big deal but surely best to source a 128/Strada/Yugo intake manifold. You really cant use your existing 128 1116cc intake manifold as it would have come with a single barrel carb. I think all 128s after '74 ( when they changed to 1290cc) and all Yugos ( ? ) and Strada came with a 2 barrel carb - which you would surely want....
Your existing 128 engine mounts should work okay with any engine. Of course the lower mount is on the tranny, so no effect there. The side engine mount is the same I think on all X1/9/128/Yugo. Not sure about Strada. Use the 128 top dogbone mount.
All the 1116/1290/1500 blocks were basically the same. The only big difference is with the 1500 blocks - they were about 1/2" taller at the top of the block due to the longer stroke. The extension was above where the side engine mount bolts on so that is okay. But that does mean that whole head will now sit 1/2" taller in the car. So watch out for hood clearance, rad hoses not quite lining up, throttle linkages, front exhaust pipes too short, dog bone not quite right, stuff like that....
I'm curious about your other engine block. If it is marked 138 it is most likely a 1500 if it came from a US market X1/9 or Strada ?? Easy to tell - just run a tape measure from where the pan bolts on to where the head bolts on, on both your engines. If same as the 1116 measurement - it would be most likely a 1290. If 1/2" or so longer then it would be a 1500.
Hope this helps. Good luck. Doug
