Was wanting to get some thoughts on this. Would it be possible to bore the 4.8 .040 over to 5.7 spec and put a ls2 crank in to achieve 383 cubes? Take it easy on me just an idea.

 

The ls2 crank has the same stroke as a 5.3. Your 4.8 is the same bore as a 5.3, just a shorter stroke, hence the smaller displacement. If your building a 383 you'll be running a new 4.00 rotating assembly, combined with boring the block out to ls1 specs to achieve 383ci, so it would be the same as starting with a 5.3. There's a ton of those builds on here.

 

You'll need to bore it .118 over for stock ls1 bore along with a 4'' stroke crank

 

To confirm what's been said, you will need to bore the cylinders out way more than 0.040" to achieve 5.7 specs. The 4.8/5.3 blocks have a stock bore of 3.780" while the LS1 has a bore of 3.898". Most 383 rotating assemblies use pistons that fit a 3.905" bore. Find out what you plan to use first before having the block bored out.

Using a LS2 crank won't work for a 383 stroker. The LS1 and LS2 cranks use a 3.622" stroke and a 383 requires a 4.000" stroke. You have to match up the right pistons for whatever crank you plan to use, because the pin height is dfferent for various strokes.

A good balanced forged 383 rotating assembly will probably cost about 2 grand. A low budget build might be finding a complete used stock 5.7 rotating assembly and make a 5.7 engine (346 cubes).

 

Ls1 bore is 3.898

 

Yep, you're right. I knew that, but just made a typo. I corrected my post.

 

Figured it was

 

Yep, you'll need to bore 1/8 of an inch and use a 4" crank. It's a lot of machining work to bore that much material out, though the results are impressive.