anyone know towing, 5,3 vs. 4.8

[mopower440]

on the 1999-06 trucks, can anyone tell me from experience, if the 5.3 tows a lot better than the 4.8, given they have the same rear gear ratio..?I know theres not much difference in the torque and horsepower numbers, so am really wondering.. I have a 1999 ecsb 4x4 3.73 gears, and tow a boat that weighs around 3100 lbs with trailer and it has to downshift constantly to go up any incline and it struggles more than i like. My buddy has the same truck, same gears, only his has the 5.3 and he tows a little heavier boat and says his doesnt struggle at all, goes right through the hills and all with no constant downshifting. anyone have any real world experience between the 2 engines towing? heck, my old 1989 with the 5.7 TBI, didnt care how heavy the load was, it would hold 70 down the interstate through hills and all!

[RS/SS 4.8]

4.8s dont like to tow. Mine doesnt even like 500lbs in the bed with 4.10s. 6.0 is the answer.

[mopower440]

i know about the 6.0 but wondering about the 5.3 vs. the 4.8

[RS/SS 4.8]

If its a 4.8 vs 5.3 then the 5.3 takes my vote. The stroke on the 5.3 is the same as the 6.0, 3.622 while the 4.8 crank is like 3.25 or somethin close, longer crank=more torque and therefore struggles less when towing/hauling. If u want to keep the 4.8 maybe some lower 4.10s, 4.30, 4.56 ect gears may help.

[mopower440]

na, im going with bigger engine. The 6.0 is 2 1/2 times the price of a 5.3, and money is tight, thats why im want to do the 5.3 and not the 6.0. BUT, if the 5.3 didnt tow a good bit better than the 4.8, i wont swap the engine, thats why i was asking. I guess im wondering will the 5.3 be a lot better on towing than the 4.8..I knew it had to be better with the longer stroke and all, but how much better..

[RS/SS 4.8]

Thats a good question. See if your buddy lets u borrow his and see for yourself. You can try contacting Nelson Performance (Allen runs around under the name of farmtruck on here) about a custom tune. That may help enough and only runs about 300 last time I checked. Oh by the way you should see what the 07+ 6.0 cost.

http://www.nelsonperformance.com/
210-626-0278

[kerrige]

I think the very best thing for you would be a gear swap. A 5.3 with flattop pistons would be awesome and a dramatic towing upgrade. Stock for stock a 5.3 will be 20% better IMO. The 4.8 is a rev happy motor that isn't the best for towing. The 5.3 also responds much stronger to Bolton's. However, nothing you can do with the exception of a 6.0 swap, is to swap your gears. 4.10s or 4.30s will help you move out quicker and at cruise will hold a lot better. Also reducing stress on the transmission and other drive line parts. A 5.3 with flattops some Bolton's and gears will get you a great setup. Also if you plan to tow a lot you should look at a big trans cooler. My trans temps soar when I tow. Add a 40k true cool and it will stay cool in the hottest summer days.

[mopower440]

well, My old 1989 chevy with 350 TBI and 3.42 gears didnt care what was behind it. It never had to struggle. would the 5.3 be more like that? wondering if the 5.3 is comparable to the old 350 OR, the 305? Im thinking the 6.0 is more comparable to the old 350 and the 5.3 is comparable to the old 305. OR is it the 4.8 and 305 similar and 5.3 and 350 similar? (comparing towing)

[ImportThis]

Never curse a ls engine comparing it to an old 305!!! Before spending the money to swap from a 4.8 to 5.3, swap gears. You'll notice a big difference in pulling power going from 3.73s to just 4.10s. IMO if you're going from stock 4.8 to stock 5.3 you're wasting time and money. Now if you swap a flat top (or mill your heads a bit) 5.3 with a towing cam, and LT headers with a tune, then it would be more feasible.

[bootlife]

I have a 5.3, my friend has same truck with the 4.8, and my 5.3 will out tow him hands down. Taking off with a full size truck on a trailer feel a lil sluggish, at about 55 to 65 you have to watch your speed, my 5.3 wants to run 70. I have 4.10s to but not a lot diff than the 3.73s I'm running 33in tires so it's close to when it was all stock. You already have a 4.8 I'd do gears, and bump up the stall so you can stay in the mid range power that will help a lot. Tune will also help