408 is simple why complicate things with a 421? I always figured you for a total do it yourself,tear down re-assemble hit the key a little tuning and be done.Bud you have a heavy truck ,cubes over high flow dollars.What I am suggesting is K.I.S.S and bang for the buck.

Hey there is always more than one way to skin a cat ,I couldnt resist giving you IMHO

 

You're right gonzo....I do all of my own work, I saw a couple of offers out for .030 6.0 blocks and kinda thought about buying one and doing the 421 assembly myself. a 408 WOULD be cheaper for me to do and the extra 44 cubes would certainly get my monster going better than what I have now. What does a 408 rotating assembly cost anyway ???,

 

The only way I'll be bowing down is to pet your poor HD on the bumper to make it feel better when it sees nothin' but taillights for 1320 feet

 

Shop the pee out of it and would would hope for $2100 balanced,44 cubes? yes but is it worth all the BS and $,the difference in power would be in tuning and the right matched parts in the 408.I could explain futher but i think you get the drift.

 

Yelo
I have in the pipe line a 06 CC vmax,also have a radix in the wings(in my shop).I need SC because I live at elevation,I may do cubes so day and almost did at one time.I am looking at your truck like you and how i ran my 2K .Its a daily driver and it has to be dependable 1st drivebility second and performance last with the goal being bang for the buck.

 

The 408 is the extra 44 cubes......the 421 would be 57 cubes. $2100 is pretty good, that means with the bigger cam, heads and converter I could get away with this for under $4500, If I skipped the heads or went with stock #317 heads I could do it for under $3700.....not too bad and well within my price range

 

THATS WHAT IM TALK'N ABOUT

 

If you were running a 2x4 1/2 ton I would agree with your first thoughts.

 

Alright already....you 've convinced me

Those are my goals in exactly that order.....that's why I've been so picky and taken so much time with my mods, they've GOT to work the first time EVERY time. I'm pretty sold on the 408 now....how much work will be needed on the shortblock once the stock rotating assembly comes out ?? Am I talking machine shop work or just a light cylinder hone and then stuff in the new bearings and rotating assembly ??

 

depends on what she looks like inside.

oh how my Radix'd 364 will like stomping that NA 408! Just remember Al, I've been to the track

Seriously though bro, you know I wish you all the best. My advice is let everything soak in a few days and then make your final decision.
When it's all said and done I'd say your looking at 5k either way, or at least I'd plan on that much, little things always seem to find a way to pop up.