Quote Originally Posted by whoender View Post
Headers and downpipe, should I do anything to the heads? I am a tech and have been for over 20 years so the labor is not a problem
Most headers will come with a downpipe already. Assuming you live in an area that doesn't have inspections... scrap that cat and get some of your money back.

You don't have to do anything to the heads on a 3.4 setup with headers. If you want to get more serious, you could run high ratio rockers or an S1X cam... although in either case you'd need stronger valve springs (and there would be reliability and performance gains by upgrading the lifters and pushrods at this point), it isn't essential. If you wanted to run a bigger cam... an XP, an S2 or S3, etc... then you'd need some ported heads.

This thread is a pretty good start and will repeat many of the things I've hit on here. It's not perfect, but it's got most of the info on hand:

http://www.grandprixforums.net/threa...ding-Your-3800!