Just some Questions needing answers

[Cthibo500]

Looking into doing a LSx swap. wondering if anyone can point me in the right direction and info.
Looking to build a MILD motor. i'm wanting an all aluminum 5.3 so from what i read its a L33? they're available in 2005+ models? I dont mind the DBW because I want to be able to put the pedal in whatever position I want for heel toe downshifts.
For mods I'm shooting for 400HP and I want it to freely spin 6K. probably have the heads polished and a mild cam. Would a different intake be worth it? I dont like the original 5.3 looks like ****. LS1 vs LS? which one is worth the money. Also, would a bigger throttle body thats DBW be worth it?
Theres no A.C so I'm not worried about that.
as Far as ECU's and Wiring. should i shoot for Factory Wiring or get an aftermarket kit for it. if so anyone have any good locations for them? the ECU will be factory. I live in an area that does not have much for tuning shops so that is kind of out of the question. unless I sent it out.
Transmission WILL BE a TKO500. Want some OK mpg out of it. also thinking rear gears as a 3.73 gear ratio.

Truck is a 1981 C10 Stepside. weighs aprox 4000lbs.

any tips and pointers would be greatly appreciated

[Critter]

Are you talking 400 hp at the crank or at the tires? If you are talking about crank hp then a cam and good tune can accomplish that (usually). No need to change any of the other stuff. If you are talking wheel hp then more will need to be done.

One thing to note, you can't just bolt and LS1 intake down to a truck LSx motor without swapping other parts also. The front accessories have to match the intake. In other words if you put an LS1 intake on a 5.3 the throttle body will be pointed right at your idler pulley/belt.

[OKGMC4]

All aluminum 5.3's are more rare, they came in Z71 trucks for a couple years, a few SSRs, and I think some of the trailblazer EXTs. They usually cost more than the common LM7. Instead of modding it out and going to the trouble of peicing together an intake swap, if you want 400hp just find a complete LS2 that has the power and good looks to begin with. It will be less of a headache to get in and running. I have an iron 5.3 and it runs good but I find myself wishing I had held out for something more pretty often.

[BR3W CITY]

Originally Posted by Cthibo500

Looking into doing a LSx swap. wondering if anyone can point me in the right direction and info.
Looking to build a MILD motor. i'm wanting an all aluminum 5.3 so from what i read its a L33? they're available in 2005+ models? I dont mind the DBW because I want to be able to put the pedal in whatever position I want for heel toe downshifts.
For mods I'm shooting for 400HP and I want it to freely spin 6K. probably have the heads polished and a mild cam. Would a different intake be worth it? I dont like the original 5.3 looks like ****. LS1 vs LS? which one is worth the money. Also, would a bigger throttle body thats DBW be worth it?
Theres no A.C so I'm not worried about that.
as Far as ECU's and Wiring. should i shoot for Factory Wiring or get an aftermarket kit for it. if so anyone have any good locations for them? the ECU will be factory. I live in an area that does not have much for tuning shops so that is kind of out of the question. unless I sent it out.
Transmission WILL BE a TKO500. Want some OK mpg out of it. also thinking rear gears as a 3.73 gear ratio.

Truck is a 1981 C10 Stepside. weighs aprox 4000lbs.

any tips and pointers would be greatly appreciated

I'd stop and re-consider trying to setup for 400hp and not even get a tune. Aside from the fact that it won't even run (vats,emissions), tuning is a big power source from an otherwise stock engine. You'r stock injectors won't like 400hp either.

Truck engines can do the higher rpm's that your asking, but I'd think about putting in a new or a better oil pump and a new timing chain from the start. The truck intakes lose power up top, so your correct in looking at the ls car intakes. I don't know about running the DBW truck throttle body on a car ls intake though, don't know what people have done to that end.
Obviously pic a cam that fits your power goals, but pick up a good set of valve springs and hardened pushrods along with it while your in there. Lastly I'd think about replacing or upgrading the lifters, some had needle bearing failures at higher rpm...there are aftermarket units that address this....tho many folks run good numbers reliably without them, at higher rpm you run greater risk of failure.