Reckless(moderator on this board) bored a 5.3L block out a long time ago to standard LS1 size. The 4.8/5.3L blocks can go out to 3.9" but, that's it. They may even share the same cylinder liner as the LS1/LS6 but, that is just speculation on my part.

The 4" stroke is no problem.

 

The easy ticket to big cubes would be get a 6.0 block and a 4' stroker crank. That would give you a 402. Punch it out another .030 and you will come up with a 408. I would like to get my hands on a cheap 6.0 and do that, either the 408 or 402 depending on what lind of shape the block is in.

Forged 408, 8.5:1 CR, stage2 6.0 heads with about 12-15 psi of boost from my RADIX ..

 

Yea, Flyer, the 408/427 option is definitely the ideal. I was able to pick up my current 5.3L on Ebay for $300, total long block. The 6.0 is harder to come by for the time being but is being used more with the Caddie's and the SS models. I would like to do the Lunati stroker kit but the $4000 price kinda blows the budget. The Radix system is basically the same price and will probably be the next step if anything.
Again, thanks for the help folks!!!!

 

Eagle just came out with a 4" stroker crank that is available for 900. I think someone said one of the sponsers has them for 800 though, I don't remember what sponser though.

That and a set of rods and pistons could build you a forged engine for about 3k I would bet. Sounds like a hell of a plan to me!

 

Why not just use the stroker crank?? Whats involved?? Its seems like a safer more cost effective way to go. Maybe Im way off, but Im thinking seriously about doing the stroker crank. What would be some costs involved??

 

I have a 5.7 ls6 could i just use the 4" crank and have me a stroker. Or would I have to bore it out some?

 

I'm not sure about these LS1 motors, but I know that a regular small block more than .040 over becomes "unstreetable" due to high temperatures caused by thin cylinder walls. I don't think its possible to take an LS1 .120 over, but I can see where your heart lies. LS1 (5.7) blocks are readily available and are reasonably priced. I say go that route. I may be wrong, and if so somebody let me know. Then I can take my foot out of my mouth and stick it back in my ****!

 

If you went with the stroker crank you would also need the adjusted rods, too. If you tried ot use the stock rods you would push the piston into the head.
BADMOFO, the truck iron blocks are good for the 0.120 overbore with room to spare. I had mine bored to 3.900 from 3.78 and sonic checked. I am going to pick up the block today and will try and post the sonic check sheet.
I have seen many people overbore the LS1 aluminum blocks but it involves re-sleeving. There are iron sleeves in the LS1/LS6 that are pressed out, bored or replaced, and re inserted. This could cause some issues later down the road but I hear rumors of up to 427ci/7.0L displacement after. This is what is done to the C5R race blocks in the Corvettes.
In all, there are huge possibilities with ANY of the GenIII engines, truck or car. Imagination and the all-mighty dollar are the only limitations!