383 out of a 5.3

[gojo83]

So I was stumbling around looking for ideas online and stumbled on an article in super chevy and it got me thinking. It said that a 5.3 can be punched out to a 383. I was thinking about this for a second and if I did that route would a stock ls2 or ls7 cam fit and work in a setup like that since its closer in cubes and would retain stock like drivability. I have an alum 5.3 that is out of an Envoy that spun a bearing and I have been sitting here thinking that since I am working 2 jobs and bringing in a bit more toy money/ move money I am looking at options and possibilities.

The project its going in is a 93 s10 blazer backed with a 4l80e hd 4wd since the alum motor is just about as light as the stock iron 4.3 that is coming out or maybe with in 50 lbs. That is approximate according to the sites I found in a quick google search. This means the suspension should be "ok" for the time being to get the motor in there and make it a rolling project instead of it sitting waiting on an appropriate suspension.

I have also been talking to a buddy and he said "dude just run a shorter stroke like stock but punch it out to 347 CID so that you could use cheaper stock size pistons instead of an odd size that is more pricey. If you are even debating boost no matter how low of boost you want to run the alum is known to not take boost as well as an iron block." I said I know, but I am not looking to break any records. This will be the rig I use to chase storms and my thought is with boost e85 or premium is required and some of the little towns around Nebraska (including the town where my parent live) and others only have low and mid grade gas which could have some serious pinging issues or Knock issues unless really detuned. This is where a 383 with a ls2 or ls7 cam could potentially run on mid grade with lesser issues and still have 350-450 whp.

For longevity and low maintenance would you say there is no replacement for displacement or boost is the great equalizer. If I were to boost it I would look at a T4 72 trim turbo on 7-20 psi. 7 psi for daily driving then if I felt froggy bump it to 12-14 psi for a street drags at the local track then 20 psi for when I want to push it and try for PB. I would go intercooled no matter what, so I would not run a hot air setup to help reduce any knock from just super hot IATs.


This is mostly me thinking out loud and looking for advice before I consider dropping any really big coin on this project.

[Sahara54]

Why waste money on punching it out if its not needed? Just get the crank and mains re-sized and run it as is. If you want big cubes, sell the l33 and grab a 6.0. The L33 also has a higher comp ratio than standard LM7's due to using the 4.8 flat tops so anything less than 93 while on boost is not very wise.

[gojo83]

Well just brainstorming mostly now. Now u said it is a flat top piston motor I am now going to have to check the piston to valve clearance with a ls2 cam

[Sahara54]

Yeah, L33 and 4.8's were flat tops. 5.3 and 6.0 had a dish. You''ll benefit more from a 6.0 down the line due to head choices.

Stock LS2 cam shouldn't have any problems. Guys run them all the time.

[gojo83]

I have a lq4 but idk if I want all that more weight on the nose