I'm not blowing smoke up your ***. How about you go look for yourself. The search wasn't working, but here's one that was at the top of the list. All the parts for an LS1 shortblock for $470 before bargaining.

 

Here are some more...

https://ls1tech.com/forums/showthread.php?t=734647
https://ls1tech.com/forums/showthread.php?t=726549

The older ones have been sold already so they don't show a price. But there have been 10-15 shortblocks for sale in the last three months or so.

 

So all you got to do is bore it out .126 to make it an iron block ls1? What would be capable of more power ls1 or 5.3 to 5.7? Which one would be cheaper....buying a used 5.3 and boring it out or buying a used ls1? Subscribing...

 

if you buy a used LS1 your taking a chance that the machine shop will tell
you the walls are too thin and they can't do it.

since the 4.8/5.3 block was made to be punched out to a 5.7 bore.
you stand a better chance of having an iron block 5.7 with thicker cylinder walls.

 

This would be the best bang for the buck.

 

even if you pay more for a LS1 short block, 100 lbs off the front end is worth some extra coin IMO

 

yeah but an iron block vs an aluminum block when boosting is worth the extra 100lbs insurance

 

Actually yeah... since you are boosting, why not get a 6.0 iron block, throw in a stock crank and invest in a nice set of rods and pistons. Also think about a set of 6.0 heads, you can touch them up or not, they work pretty well stock for boosting. You can stay under $2000 and have a near bulletproof platform for boosting.

 

Also, later down the road if you are looking for more hp. That motor is very stout foundation to build on.

 

So there's no half way point from 5.3 to 5.7, eh? Woulda been kinda nice to have another rebuild in there. Oh well- how many generations can you keep a truck for...........