If you installed a k&n filter and a flowmaster exhaust your looking at about a 10-15 hp gain I have them both on my bird (it 's a 305) and made around 15. As far as head work is concerned (sp?) if your talking porting and polishing you can buy kits from summit or most other big performance retail mags to do it yourself. they are about $50 and can be used with a die grinder or a drill. I recommend you practice first on some junk heads. As far as performance gains in the newest issue of Car Craft they ported and polished some V8 heads on a lot of different engines and got hp gains of about 40 v6's may not gain quite so much because they have less displacement and so flow less air anyway. but this would still be a good mod to do. I want to do it to mine but I cant find junk heads to practice on. as far as what a shop will charge you
I don't really know my guess $250?
