ive decided on my build i want a 6.0. i was talking to a guy here and he said the the cast iron 6.0 truck block is better than the ls2 and cheaper but in my experience cheaper isnt better i thought i would get some more thoughts on it. secondly when i go to get heads can i put ls6 heads on to raise compression like you would put 5.3 on ls1's( this is what i was originally going to do) or can i even go with 5.3 heads or is that just too much. dont really know to much about the ls2 so any help is awesome thanks im not going to crazy with the hp i just want a streetable 500-600 hp n/a

 

The 5.3 chamber is too small for the 4.00 bore IMO. Go with a set of ls6 heads and have them milled to achieve the compression you want. Are you going to use stock heads or ported ones? If ported go with at least a 2.05 intake valve.

I would go with the ls2 block over the cast iron if you are staying N/A.

 

The LQ9 408 is $4392 from me with Callies crank and rods and Wiseco pistons. Or for $250 less with Scat crank and eagle rods.

The LS2 403 is $350 more for the cost of the block or $4742 with Callies and Wiseco pistons . SO best bang for the buck is the LQ9 408. It weighs 75 lbs more... BUT wait, thats not it... Unless you already have and ls2 you need to buy a few more things that you dont need to buy with the lq9... like covers and adpapters and such bringing the price up even more... further making the 408 the better deal/ The lq9 will take your ls1 stuff.

 

lq9 alot cheaper to build

 

The LS2 name sounds alot better!!! But the LQ9 is iron and if you decide to upgrade and boost the hell out of it the LQ9 block would be better.

 

i try and tell someone a lq9 and they go wtf i fo IRON Ls2 hahah they go ooooo and think its some crazy block

 

Get an LQ4 and save even more money. Lq9's will bring more because they are in the Caddy's and Silverado SS. Only 0.6 difference in CR and all other parts are exactly the same. To use your LS1 accessories, you need to drill and tap on hole in the left front of the block for a bracket.

 

Couldnt you just buy the lq9 heads to make up the difference? Or would that be irrelevant?

 

no lq4 are dished pistons

lq9 flat top pistons thats where the diff in compression comes from

 

VERY NICE NOW I KNOW WHAT I'M GOING TO GET

 

Didnt know that! Thanks for that info!

 

The LQ4 has a 6cc dish

 

6cc... wow hadnt actually seen one before! Thats pretty cool! Turbo setup capable!

 

99blancoss brings up a great point about the covers, its the little stuff like that, that can add up quick. A stock block LS2 will handle up to about 1000 fwhp, an iron block can go way past that.

A few questions to answer for yourself.
Are you always planning on staying under 1000 fwhp?
Is the heavier block an issue?
Is the extra money for covers and the price diff. on the block itself an issue?

IMO, one is not "better" than the other, they each have their own market.

If you're building the bottom end anyway, take a look at some of the SCR calcs online and plug in some numbers. Piston top volume will have the biggest effect on SCR.