I am currently working on a 429 built for propane. I am not looking for huge horsepower, but rather good low end torque and economy. I am planning on around 11:1 static compression with an RV type cam. From what I have read you want to keep the dynamic compression around 10:1. There is a lot of information on the web and there are a lot of pros and cons associated with dedicated propane fuels, you just need to decide if it is worth it to you.

Jonny