99 chevy 1500 5.3L 4x4

Well even the best after-market parts break in the trails, it just depends on how its ran and drove or abused or how well its all aligned and set up. Hard to beat the old standards with cheap dirty metals from China & plastics. That would be why its not strong.

Remember now trucks have controls with electrical switches, solenoids, modules, sensors,. Its not as reliable as manual systems, and get out and lock in your hubs from the older days, you may want to hit the trails when you did not know you wanted too 5 seconds ago, and to do so means a lack of reliability. Today if you want strong you have to find an old military truck to take parts from and even then you have to reinforce you frame everywhere. I'd say maybe 400hp if you drive well.

The 99 is my dads truck that weve been working on(i have a 94stepside) and right now the truck has the 5.3 in it with a roller rocker cam, Edelbrock intake manifold,k&n cold air intake, holly shorty headers with 3in to and from the cats (but it also has the electronic flaps to run open headers) full msd ignition system and a couple other things so shes pushing about 375-400 now we put 4:56 gears front and rear with a tru trac in the front. We had plans to drop a 572 into her but had been advised not to because the front end on the truck wont take the power which is sad because the truck is beautiful and even if we didnt drop the 572 in her the 5.3 has so much potential its a shame...... so basically we would have to replace the whole front end assembly in order to put more power in her without destroying the one she has?