I currently have a scsb gmc sierra with a 4.8L. I was going to build a single turbo setup for it and shoot for 12's... but now I've changed my mind. Since I have another 4.8L shortblock in my garage I thought I would use that for a starting point to build something better then just a little 4.8L. I have done some research about people building 5.7s out of them and even using them for stroker build-ups. The one main concern I have about building a larger displacement engine with this block is the ammount of material that has to be bored out and if there will be an adequate ammount of material left to run 15-20psi of boost (600-800whp).

Here is a link to a kit I recently found for a very fair price.
http://cgi.ebay.com/ebaymotors/LS1-L...spagenameZWDVW

I plan on running either extensively worked truck heads or a set of worked ls6 heads. I will be shooting for low compression somewhere between 9 - 10:1 and plan on running a Borg Warner s475 or s480 turbo using flipped truck manifolds and a custom crossover.

I would like to have atleast 370 cubes but I have also seen the 383 and 395 kits. Some more info would be great on which strokers perform better then others.

Thanks,

Tony

 

I think you can do a forged stock displacement 6.0 for less than the stroker with similar performance.

 

Well before I make a change in heart and buy more parts then I need to, I would like to find out if anyone knows how thick the 4.8/5.3 blocks are after they're bored to a 3.903-3.905" bore. If they still have a thick enough cylinder wall thickness then I think I would be ahead by doing a stroker engine out of a 4.8/5.3 block considering I basically have another good running engine in my garage.

 

You will have to get a 4.8/5.3 block tested to see if the wall are thick enough to bore it out to 3.905. I ran an 11.35 with a 370 block, stock 317 heads, sts with t-67 at 12 psi. With a turbo you don't have to dump alot of money on heads and a cam or a stroker kit. A forged 5.7 or 6.0 will get you into 12s with 7-8 psi and a good tune easily. Research and see what some of the other guys have done before you start throwing a ton of money into the engine. You will need it for the tranny and rearend.

 

I am well aware of what 6.0Ls and 5.7s can do. My brother has a scsb 6.0l truck with bolt ons and it scoots good. I know there are people here who have done the 4.8/5.3 - 5.7 builds and have bored them to 3.903-3.905". So I KNOW they can be bored that much, but without .250" thickness on the cylinder walls after being bored to a 3.903-3.905 it would be rather worthless to build anything making more then 500hp in my opinion and expect it to last. I have done a lot of research on what people are running on here... and I know you can go deep into the 11s with a 6.0L and boost... but it is also apparent that more c.i. has more potential for power too, and that is why I have brought this question to the table.

 

why not stroke a 6.0 to a 408 or larger then?

 

Well a 408 would be nice, and if I had a 6.0L block that's the route I would go. Since I have another 4.8L engine and I can make up to a 395 out of (only if there's .250" or more cylinder wall thickness after boring it) I would like to go that route instead of spending probably 300-500 for a block when I'm only going to gain 13 c.i. by building a 408.

 

food for thought anyway. you'd recover some of that loot with your spare 4.8 and whatever you sell from your present one, and have a much more durable motor to handle whatever you can throw at it. i'd just be nervous to punch a 4.8 out that much.

 

You do have a good point about selling the 4.8. I would still like to know just for my own sake what the cylinder wall thickness is after boring a 4.8/5.3 block. If anyone has any information on this I would really like to find out. I guess I might start looking around at prices of just a good 6.0L block to build a forged stroker.