Better impact....which choice?

[iluvmy72]

OK I need to geta engine in my 96 2500 4wd burb....I was thinking about a 4.3 but have since discovered there is a big weight difference between the burb and astro van so I need more power. So my choices are now limited to finding a 5.7 Vortec along with all computer controls. Or I can have my 7.4 Vortec rebuilt and not change a thing. What I am wondering is how much of a difference would I really see in mileage in exchange for the headache of changing everything? Because I still have the 4.11 gear ratio in the back, I cant afford a 350 change over and a gear swap. However I can afford a rebuilt 454 with a 3.73 in the back. My question is would this eual out and what would my milage be with the 454 after I change the rear gearing?

[MonteSS454]

Ok you have a 3/4 ton Burb that came with a 454, rebuild the 454 and save the headache.

A wiring harness swap, computer swap and engine sway will be to big of a headache.

Either way you're not going to get great mpg with it being a 3/4 ton burb so just keep the 454 and you'll get about 15mpg or a lil less.

[iluvmy72]

What if I was to add a electric fan, dual exhaust, street legal headers, performance cats and mufflers? Would that help in mileage?

[MonteSS454]

Add that to the 454 and you'll do alot better.

[iluvmy72]

I might also change the gearing on the rear end. I think that would do wonders!!!!

[impalamark]

Mark

[MonteSS454]

You going to put towing gears in? Lower gears means reduced mpg.

[iluvmy72]

LOL...did I mix that up? I will be putting in a more fuel economy gear ratio.

[finch]

I have 3.42's in my 05 with the 5.3 and it still has plenty of get up and go for me...1500 RPM at 55, can't beat that.