Hey guys, i used the search function but got mixed answers... Two questions

The 4.8/5.3/6.0 Iron blocks, are they physically the same size and appearance on the outside? As in, can i easily disguise a 6.0 as a 4.8?

Also, is it possible to de-stroke/sleeve a 4.8 to make it a 4.2 LS... Reason being, laws in Australia suck. With the weight of my vehicle, the largest engine cc i can go turbocharged is 4284cc/4.2L.

If it is possible, how would i go about doing this on paper?

Thanks
Jeremy

 

Yea 4.8/5.3/6.0 are physically same size...only difference is casting number for engine size is to the right of the timing cover...5.3/4.8 are the same block whereas 6.0 says 6.0...are they that strict down under?

 

Yep, very strict. And i want to keep it "legal" for insurance reasons.

 

It's not impossible, but I just did some calculations, and with a stock bore, you'd have to have less than a 3 inch stroke to get down that small, and sleeving it, your going to get the bore so small, it's going to shroud the valves so bad it might not be worth it.

 

Time for a vortec 4.2 liter v6 out of a trailblazer/envoy

 

Atlas engines are inline engines. 2.9, 3.5 and 4.2 are i4, i5 and i6 respectively.

 

I'm not actually going to do this.. I just want it to be viable on paper. If that makes sense...
Nobody opens up the engine.

 

It would be harder with a 6.0 since it’s stamped on the block. Some of the early blocks do have 4.8/5.3/6.0 stamped on them. May have a tough time finding one though.

Just grab the common 5.3/4.8 block and indicate that you had custom rods/pistons made to destroke it to a 4.2.

72mm stroke on a factory bore 4.8 would give you 4.294cc. Slap in some tall deck pistons to take up the 11mm stroke loss and your golden.

 

Well yes you can take the 4.8/5.3 block and bore to 3.9x easy. There are some guys that have taken it to 4" , with no problems. But if I was going to try 4" get it sonic checked for wall thickness. Answer 5.7 is doable and 6.0 maybe.