I have a 5.3 iron block sitting around and I was wanting to know if the 5.3 and the 6.0 are the same block, just a different bore? If so how much do you think I could bore out the 5.3 and still be safe enough for daily driving. My buddy owns Abbott Racing Heads/Engines, and he said if we bore it to a 355, use a stock LS-1 crank, forged internals, mild cam, and a set of his heads it will put down around 360-370 at the wheels. But I'm thinking if they are the same block I could bore it to a 6.0, maybe a little larger and make some more power and probably alot more torque. Let me know what ya'll think.....

Austin

 

different block.

 

I have heard that cast iron blocks can take a 3.910" bore and still be ok. It has also been said there is enough "meat" in the cylinder walls to allow for this. The stock 5.7 bore is 3.90" and that is 0.120" (almost 1/8 inch) larger than the stock 5.3L bore at 3.78". I guess you could do it but it might not hold up under boost/nitrous and what not. If you are "gung ho" then shearwave the cylinder walls to check the thickness. If not then go with a 5.7 aluminum or better yet, a 6.0L block, you will be glad you did. I saw an LQ4 (6.0L cast iron) on ebay for under 200.00.

5.3L + .120 overbore =

 

i think you can bore a 5.3 to a 5.7. not 100% though

 

Don't know if you've seen this site:

Gen III info

Hope it helps!

 

I took a 5.3 block to the shop today. I wanted it bored out to 3.905. They said they would not do it for F/I. Said it would be risky N/A. They know their $**t and build some serious cars, so I trust them 100%.

 

Well I don't know what I'm going to do then. I don't know if I want to start looking for a 6.0 or just go ahead and bore this one to a 5.7. I'm gonna have to do some thinking! Thanks for the info guys....

Austin

 

i'm not a fan of boring an engine that big, especialy when bigger bores are available.

 

http://cgi.ebay.com/ebaymotors/2001-...spagenameZWDVW

 

I bored one to 3.905" for an NA motor build. Thinnest post bore area was 0.157" with sonic check. I have even seen them on eBay may times already bored using torque plates ( very important ). i had no sealing or compression issues after.
The bare, short, and long 6.0L blocks are getting more affordable now. I probably spent $400 on machine work ( got the mains honed too ) then dropped in a 4" stroker crank for a 383ci motor. Made great power once the tuning was done.
In the end I might have saved a few hundred bucks plus the bragging rights for a DIY project over a 402 or 408 shortie. There are a TON of stock rotating assemblies for cheap out there if you want to go budget iron LS1, I just could not resist the temptation of the stroker.