The Doug Thorleys fit great. They require new plug wires though. I went with Red adjustable boot angle wires from MSD. Ordered at Autozone. My 5.3 is set on 6 cyl stands in back set of holes, using stock v8 rubber mounts for 68 c20 and homemade adapter plates using pattern on LS1tech.com. The only problem I had was the collectors dump close to the tranny crossmember and parking brake lines on both sides. The exhaust man I use enjoyed that. The tranny crossmember was moved forward for the 4l60e by 2 inches by the way. Aftermarket crossmember would have done away with that though. Good luck with your project. Here's a little incentive to go with the DT's.
