vortec 5.7L

hey ya'll, i have a 98 k1500 with the 5.7, i have about 300000miles on her and she is still running like a champ, anyways i am just looking into some plans in the future for when i tear into the 5.7 to give her new life.  She makes good power but when i rebuild it i want to punch a little more out. I was thinking maybe a new multi port injection system with a better intake since the scfi on her is not the most wonderful invention ever.  I really like the vortec heads but i was wondering how a port and polish job would do, the thing about it all is i dont want to sacrifice torque, i use it for hauling and towing so the torque is a must. Any insight would be great.  

Anything you do to increase porting and polishing is going to decrease lower RPM torque. The old TBI 350's were the lower RPM torque champs over VorTecs because of intake and port design in head. The traded lower RPM power for more top end performance on VorTec. What you likely need more than a rebuild is a nice set of gears in axles because they can do wonders for 4x4's especially lifted ones.  

Hey thanks for the thoughts.  On the topic of gearing, i have 3.73 and i just have stock 265's which are about 32's if i am not mistaken, i think 4.10's would work a little better though, what do you think? Also i was wondering about the factory locker in the rear, it used to work pretty good, but lately i have noticed that it isnt engaging, should i just swap it out for an aftermarket Detroit locker or can you rebuild those factory lockers?  

1500's never came with 265 to my knowledge but they seemed to find their way on many. On axle ratio, 3.73 is tall for 32 and a 4L60. A 4L60 has a .70 OD gear and it will not pull it well. A 4.10 would be a better minimum gear here with 4.56 even better because even with 4.56's you will be turning less than 2200 RPM at 65 in OD which is about right. On locker, your G80 GovLoc is actually a LSD diff  and in your 10 bolt axle it is not very strong and will not take much abuse to bigger tires (30's is about it for that diff in that axle if you play hard and expect it to last a while) With even bigger tires than your it is know to grenade at times. In bigger axles, the G80 holds up much better.  

265s came stock on obs 1500 z71s

3.73 gears are plenty for 32s IMO...

I blew a g80 with 33 swampers.. its weak

snoman if your tellin him he will be turning less than 2200rpm at 65 with 32s and 4.56 gears your full of *** I was turning 1800rpm at 70 with 3.42 gears and 33s. I now have 4.88 gears with 38s which is a actual ration of about 3.80 I turn 2250rpm at 70 mph  

You are wrong and 3.73 being plenty with 32's and a 700R4/4L60 unless you have very low standards because it will have slug like properties in OD and downshift/unlock a lot.

BTW, I am not full of it on RPM! You can run number yourself if you want because your numbers are off. If you have a 4L60 and 4.88's your effective ratio in OD is 3.4 to 1 and rpm at 65 would be about 2000 RPM(BTW, 4.88 is too tall for 38's anyway with a OD tranny) If you are turning 2200 it is because speedo is off or tranny is slipping.

Click on link below to run numbers yourself

Click Here  

the convertor in the 4l80 and the 4l60 will run ya about 2200 if it's not locked and riding on the stall regardles of your gears... especially running with tall gears and big tires.

if ya have the 4l60 or 4l80 and do alot of towing
ya should leave er in 3rd and run 55-60mph with 32" rubber and 3.73's, otherwise you'll be fixin a tranny sooner than ya should have to.
55-60 runs around 2200rpm's and gives good ecconomy and runs the engine where it needs to be for towing.  
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