I have 4.8 liter silverado that I would like to modify. I want to get a 5.3 punched out to 3.893 making it a 5.7, so naturally I have a couple questions about what I will need and what I can get away with.
1. Will I need different heads or will the stock ones work fine with 5.7 head gaskets?
2. Does anyone have suggestions for what cam to use?

This will be a daily driver/light towing vehicle for reference.

 

1. Stock heads are fine.
2. Any cam with less than 224 degrees of duration will work just fine for towing..in general. What gear are you using? More (lower number) gear= *you will want* less duration.

 

What do you mean by gear? As in axle ratio?

 

Yup, he is referencing what gear ratio is currently in your truck or what ratio you plan on using

You can use any crank that is not a 4.8
Same for the rods, as 4.8’s are slightly longer then 5.3,5.7,6.0 etc

 

That's got me thinking, have you heard of anyone just boring out a 4.8 to keep factory crank and rods? I'm on a college student's budget for this project. I'm also going to replace the lifters since I've got the all to familiar chevy tick. Also, will I be able to retain factory fuel pump/injectors? Will I need to have my truck tuned after this?

 

Fuel pump is fine on a just a cam swap and engine size increase. Factory pump can support a 6.0 with a mild cam just fine.

Stock injectors should be upgraded to like 31lb/hr for extra fuel flow. Those are factory 8.1 injectors that most use.

A tune is a 100% must do, no way around this.

 

Cool, I can work with that. Do they have to be the 8.1 injectors, or will the E85 injectors do the trick?

 

If you have E85 available you can use flex fuel injectors. Also you can use marine 8.1 injecotrs. They are 42lb/hr and can be found for cheap as well.

You can cheap out and use your factory injectors and stock cam if funds don’t allow for everything. Still need to get it tuned after engine CI increase


4.8/5.3 are the same blocks ( same bore size as well )They just use slightly different rods, and the cranks are different ( same tone rings, just different lengths ) you could find 5.3 rods for probably a song and a dance. You could probably get away with 5.7 bore size and a 4.8 rotating assembly but the CI won’t be there. It would be close to around 310CI FWIW

That’s using the 4.8 crank, rods, a flat top piston, 58cc heads with a .051” head gasket

 

As for your head gasket question you would just use stock LS1 gaskets since you're boring to LS1 bore

4.8 and 5.3 gaskets WILL NOT work if you increase the bore size

 

I'm probably going to cheap out, I don't want to break the bank just yet. The bore is more important right now and I do NOT want terribly cheap pistons or machine work. Speaking of the tune, I don't have a trailer big enough for my truck. Will I at least be able to drive it to wherever I end up getting the tune done?