4.8 vs 5.3 swap

[Chuck75]

I have a 2000 GMC Sierra 1500 4x4 with a 4.8 liter in it with 336,000 miles. As I'm surprised it lasted this long I've noticed that its losing power,  and either needs rebuilt or I wonderd if swapping in a 5.3 liter would be direct fit with wiring harness and everything except a tune would be needed. I was thinking of buying a 5.3 liter out of a Sierra or Silverado from 2000-2006. With alot lower miles and putting a Tsp stage 3 cam and springs in the heads and a 9in velocity tsp intake with bigger carboyle ignition coils, and 102cm throttle body. Or should I just do all if that to the 4.8 liter I already have. I understand that the only difference between the two are the crank and tune. I'm just not sure which direction to go?

[CamGTP]

The 5.3 drops in, that is not an issue.

 

Your other plans are not well thought out at all though. Those are not really a good combo of parts. Things need to go together otherwise it's going to drive like dog ******.

 

Stock coil packs work for everything. Even a 1000hp engine, stock coils work. Upgrading those is just spending money you shouldn't be.

 

That is a large camshaft. So the cam/springs/rocker arm upgrade is good. Then you need to bump up to a 2800-3200 stall converter. Rebuild the transmission to hold this power because a high mileage 4L60e will just not handle it.

 

You'll need much larger fuel injectors, probably 33lb/hr injectors just to support this power level.

 

The intake and 102mm throttle body are overkill. This engine won't flow that much air, you'd never even come close to needing that throttle body size. The stock throttle body would be enough and the truck intake will make power.

 

A custom tune once all said and done of course.

 

Doing those mods to the 4.8 would still net you a lot less power than doing a camshaft upgrade to a 5.3. More cubic inches is going to give you more power.

 

 

Me personally for a daily driver truck would be less camshaft. The TSP stage 2 is like a 212/218 cam size. Do the valve train upgrades and stuff. Add in some 31 or 33lb/hr injectors, some headers, a good tune and you'd see a good gain in power on the 5.3. It allows you to keep a stock stall converter but still pray for the 4L60e if it's not a fresh unit.

[Chuck75]

19 hours ago, CamGTP said:

The 5.3 drops in, that is not an issue.

 

Your other plans are not well thought out at all though. Those are not really a good combo of parts. Things need to go together otherwise it's going to drive like dog ******.

 

Stock coil packs work for everything. Even a 1000hp engine, stock coils work. Upgrading those is just spending money you shouldn't be.

 

That is a large camshaft. So the cam/springs/rocker arm upgrade is good. Then you need to bump up to a 2800-3200 stall converter. Rebuild the transmission to hold this power because a high mileage 4L60e will just not handle it.

 

You'll need much larger fuel injectors, probably 33lb/hr injectors just to support this power level.

 

The intake and 102mm throttle body are overkill. This engine won't flow that much air, you'd never even come close to needing that throttle body size. The stock throttle body would be enough and the truck intake will make power.

 

A custom tune once all said and done of course.

 

Doing those mods to the 4.8 would still net you a lot less power than doing a camshaft upgrade to a 5.3. More cubic inches is going to give you more power.

 

 

Me personally for a daily driver truck would be less camshaft. The TSP stage 2 is like a 212/218 cam size. Do the valve train upgrades and stuff. Add in some 31 or 33lb/hr injectors, some headers, a good tune and you'd see a good gain in power on the 5.3. It allows you to keep a stock stall converter but still pray for the 4L60e if it's not a fresh unit.

 

[Chuck75]

Thank you I was wondering if I would really need to upgrade my intake or throttle body, or coils. I probably will go with the stage 2 cam, and bigger injectors, and a tune for the 5.3 and this motor and trans I picked up today only has 97,000 miles on it out of a 2002 gmc Sierra. I really do appreciate the advice. 

[Chuck75]

Is there any certain brand of injectors that are better than others?

[CamGTP]

Try to source some factory 5.3 flex fuel injectors from a 2002-2005ish Tahoe/Suburban and Silverado. I don't have the part number of the injectors off hand.

Those are 33lb/hr and all the data for tuning can found through other stock tune. It's a pretty common upgrade over the factory 25lb/hr injectors are normally are at their limits with camshaft swaps.

[Colossus]

That first Gen of 5.3/4.8L are goood engines.  Most get to 350,000 miles fine, it's everything else around them that breaks down like the tranny and such.