Here's some low buck for ya. Started out with the need for a two into one so I could reuse the rear half of the existing exhaust in my build. I couldn't find one locally. So I grabbed about $40 worth of exhaust parts from the local shop and mig welded one together. Not pretty, but its darn functional and fits like a glove! The alternative was about $160 for a sbc 350 Y pipe collector. There were cheap ones I found from "Walker", but they didn't get very good reviews.
