Gen III Benefits

[msb350]

Well my tried and true 350 TBI is getting near the end of its life and my gas mileage is slowly getting worse. I am curious to know what kind of gas milage I could queeze out of a Gen III 5.3 or 6.0 with an custom tune, cold air intake, and free flowing exhaust. I know 5.3 and 6.0 put out some good HP and torque numbers. After seeing all the benefits these engines have, I am seriously considering putting one in my 89 K5. Anyone else have any input on these engines. I saw that RyanB is having really good success with the 6.0 and I was wondering if anyone else is.Thanks.
matt

 

[sled_dog]

mileage? for all the technology, all the power, all the innovation, they still hven't come a crazy amount with mileage. My dad gets about 12-13 out of his 6.0 in his 2500HD(ext cab long bed loaded with tools and he has a heavy foot). Mileage will be better than your TBI rig but not talking 6.2L diesel better. I can't really say but in a K5 with normal driving I wouldn't be amazed to see 15mpg.

 

[msb350]

So driving normally in the city I could possibly get 15? I think that would be a nice figure for a V8.

 

[neverendingproject]

my moms 6.0 gets 13.5 and my step dads gets 12

 

[msb350]

are they stock 6.0.s? Basically I am trying to find out how effecient these motors can be in a blazer with a few mods.

 

[Ryan B.]

I just did a 250 mile shake down road trip today on the new 6.0 swap. Runs awsome. Had my foot in it the whole time and it probably knocked down 13mpg or so. I. That was cruising 3-3200 rpms most of the time on the freeway with my 1 ton dually with no overdrive th400-np205..
With a manual or an overdrive tranny it will get better mileage..
I can get low mileage engines 5.3's are easier and cheaper to get than 6.0's... and I could rework the harness and computer making it a turnkey setup also. pm me for more info.. Physically getting the engine mocked up where it needs to be and fabricating some sort of motor mount adapters and a crossmember is the biggest hurdle. Kevin at pacificfab.net helped me fab all that.
Pros and cons of swapping a GenIII engine into your truck:
Pros:
Lighter weight, serpentine belt conversion, sequential fire multiport fuel injection, hi flowing aluminum heads, more hp/tq, higher revving..
Cons: You must address the motor mounts, crossmember, fuel system, cooling system, air intake system....And parts cost more.

 

[msb350]

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[msb350]

sorry about that. Ryan B, what do you think would be the best route a 5.3 or 6.0? Glad to hear your haveing great success with the 6.0. email me if you get the chance.
thanks.
matt