A great combo for a heavy truck would be a iron block 346 with forged internals and the Radix....you could run some serious boost (safely) and the end result would be great linear power all through the powerband.

 

I love having options. Just a few years ago I would have been buying 2 new pistons and throwing it back together. I am feeling more strongly about the 346 than any of the combos.

 

You'd be staying with the Radix that way?... and avoiding the cost of the turbo also?

 

Yeah, I'll be keeping the radix.

 

It doesn't sound as exciting as the 392 w/turbo but it sure makes great sense given that you already have a hot car to play with and given that this possible combo still makes a dammed strong and fun truck at an affordable price. Personally I pat you on the back for having the sense/discipline to settle for the less exciting toy when it makes sense to do so. I have a hard time with that. I'm still a spoiled brat who tends to have a tantrum when I can't have what I want when I want it

 

I appreciate the compliment. I always go way overboard as well. I just have to keep telling myself that it is just the tow truck and has to get me 70 miles round trip to work every day.
I basically saw that I was about to build a motor like I want in the vette. I then stopped and tried to figure out how I was going to top the truck motor in the vette and that answered it for me. Invest the speed parts in the toy made for speed.
It's still going to have 50-75 more hp than the 4.8 due to the cubes and better heads (ported 817's).

 

I don't know what 817's are???

 

I gotta agree here...mostly because this is the route I took for my Yukon. I bought a 02 LS1 with 12k miles (you could find a 5.3 for poring to 3.905 for alot cheaper than my 5.7L), had it rebuilt with Ross -15cc forged & a set of lightly worked 317 6.0L heads. ARP main & head studs, ARP rod bolts, nitrided crank and LPE GT2-3 cam. I'm running a Radix with a 2.85 pulley at 9.5# boost, and have 425rwtq at 2200 rpm that holds til 4200 thru 3.42 gears on a Mustang dyno. My major issue with getting good hp numbers is high IATs, even with the bigger HE. IATs hit 197* in 57* ambient. Not sure how to hit 12# without meth injection. My next step is taller gears...likely 3.90s. But you can expect excellent hp & tq with a 346...don't know how much more would be gained with the 408.

 

317's are 6.0L heads.

I'd like more cubes, even though it would sacrifice boost, but I'm trying to get the most bang for my buck on the concervative side with what resources I have. I think the 346 will be plenty. A hell of a lot better than that damn 293!

 

I figured you meant 317 but thought maybe there was another part known as a 817 (your post shows 817).