I was trying to sift through your previous postings to keep you from repeating anything but my time restraints keep me from doing so. I just got my hands on a 1965 V100 Valiant 3-speed. The original 170 runs great with only 82,000 miles (just getting broken in good). I have plenty of experience with the V8 but the 6's are a mystery to me. I need to know how much I can safely bore the block and how much I can mill the heads. Can I get 10:1 comp. or am I asking to much? How about some cam specs? I am looking for something street worthy but I wanna teach a few 5.0's a lesson with something that's gonna blow their minds. I would appreciate ANY advice anyone can give me on any of these topics. Thanks a lot.

Welcome, the SL6 is pretty easy to deal with and some what common. If the 170 engine is running good (low miles) just tune it up and bolt on some intake / exhaust system improvements. (Like a Super-Six 2 bbl. and dual exhaust or at least a bigger header pipe & muffler.)

I would first dump that "3 on-the-tree" and go with the 4 or even a "home-brew" 5-speed. Add some sway bars and good tires and drive the car for a while. If you want more power, pick-up a 225 "core" and build that to swap in when the 170 starts to give you trouble (in about year 2010).

Oh, also play with the search function on this site, try searching for "170 4 speed" (all) or "cam choice" (all) to see what comes up.
DD

Thanks for the advice. I already have a 4 speed, Clifford headers and an Off. 4barrl intake for a /6. I know everyone is all for dumping the 170 for a 225 but I am going to pep this one up first. If I don't get the performance I am expecting I will then replace it. I still need to know what's the max. I can safely mill my head and bore the block. Can I get 10:1 compression or better? I have looked through most of the postings on here concerning the 170 and everyone says to swap it out for the 225. I am going to keep my 170 so this is what I need info. on. As before if anyone at all has any kind of advice for me concerning this PLEASE post it. Thank You

Well, I know how you feel about your 170, I am also running one. The one I have is bored .100 o/s to 3.5 and the head is milled .090

With a 4 bbl and headers, it runs 14.20s @ 95 MPH
DD

I ran a 170 for a while, and I would like to add... tune for revving. That short stroker well out-revs the 225 so go for revving when picking a cam. I never raced mine, but it did have the Offy dual singles and that little monkey with the 4 speed would rev like mad and destroy my brother's Falcon in every category.

I think 10:1 will be fine as long as you only use good gas and retard the timing to just below pinging and fatten up the mixture.
Based on my calculations Doug's 170 is well past 11:1 cr.

Also, consider getting some good brakes if you don't already. Stop beating on the drums, the disks will really stop you and are much more reliable.