Yes, I've seen progressive linkage. To be honest I haven't had experience with 3 carbs so how well they perform I can only say what I have heard from others. Your gonna want forged aluminum pistons since you mentioned Cast Aluminum parts. lol Iron rings for daily driving aren't bad, but check out the Ross Pistons Tom Lowe sells. I got my set for my 292 for $600. They were .040 with a 18cc dish vs 30 stock. They come with rings and wrist pins and will fit the stock rods. His sight is 12bolt.com. Also check out Larry aka Twisted 6's sight. www.T6Racing.org Here's some videos of different mufflers on inlines. Here's a couple on my 66. Flowmaster 40 series mufflers. True dual exhaust.
https://www.youtube.com/watch?v=Nw_9eGLhhzk

https://www.youtube.com/watch?v=ifh4eU5bUAo

This one has Porter Mufflers.
https://www.youtube.com/watch?v=OSexJP4kY-g

This one has a Dynomax:
https://www.youtube.com/watch?v=venOqTy5njU

And this one has a glasspack.
https://www.youtube.com/watch?v=vmx6zjqH61g

https://www.youtube.com/watch?v=KXeBTr8e1mA

Last edited by TJ's Chevy; 09/06/15 11:39 AM.
1966 C10 292/tko600 http://67-72chevytrucks.com/vboard/showthread.php?t=596643
1964 C20 292/sm420