Hey Ive got a stock 87 quadzilla and i am about to put on the LRD adjustable pipe and silencer. I want to adjust it for top end. Right now i am running the stock carb with a 420 main jet. I was wondering what size i need to change to after installing the pipe. Oh yea i live in phoenix AZ, so my elevation is around 1,100 to 1,200 ft. Hopefully someone already has this setup and knows what size jet works the best.

 

Why don't you just call LRD direct and ask them? They are very willing to help. I don't have their phone number handy...but look up their website and then check out the contacts section. LRD Performance Specialties