I got my hands on a nice AD244 145 Amp alternator at a local scrap yard which I was planning to use for this build. This is an alternator that came on some GM trucks in the early 2000s, and it’s a very popular upgrade for the LS1 guys. I made a bracket for it to match the new harmonic balancer, but once I put the engine in, I realised that it wasn’t going to work. The mounting bracket on this alternator is just not ideal for this build. It would take a lot of modification to the alternator body in order to make it work, which I wasn’t really too keen on doing.
The original Porsche alternator on the other hand is a pretty easy fit. Renegade sells a bracket for around $140, but I think you can make one yourself in an afternoon with some scrap metal. The front bracket mates directly to the block and requires a spacer to align the pulley with the harmonic balancer (you will also need to file down the block in one spot where there is interference). The rear and the top brackets require a custom mount. Save yourself some trouble, and make the bracket while the engine is still out. Below are some pictures of what I made. These are not the finished product, I still need to buy proper bolts and give it a coat of paint.