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BossHogg69 · 12-30-2012, 09:37 PM

I think getting 19mpg in a 3/4 ton crew cab long bed will be extremely tough. Best I've ever gotten in my '05 GMC Sierra 1/2 ton 2wd ccsb is 18 on a straight highway drive going 60-65 mph, with a 5.3/4L60e and 3.73 gears. My truck weighs 5200# with me in it according to the scales at Reed Recyclers in Little Rock, AR. It usually gets mid 17's, but if I get on it very much that number goes down in a hurry.

FWIW, my '69 C10 swb would get 15mpg with a stockish 461 BBC (RV cam & 650 Holley) when I had it in front of my TKO500 5spd with a .68 5th gear. I tow with my GMC fairly often, and it does okay, but its definitely no big block.

As for the 'cool' factor, nothing about a stock plastic engine cover, ugly truck intake, or coil on plug valvecovers from a 5.3 look cool. With that being said, when they are detailed with some aftermarket parts, LS motors can look very nice - 68Stepbed's LS conversion is probably one of the best looking LS motors on this site. This post probably won't help you much, its just my .02

12-30-2012, 09:37 PM	#15
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: 454 vs. 5.3 efi vs. 5.3 carbed I think getting 19mpg in a 3/4 ton crew cab long bed will be extremely tough. Best I've ever gotten in my '05 GMC Sierra 1/2 ton 2wd ccsb is 18 on a straight highway drive going 60-65 mph, with a 5.3/4L60e and 3.73 gears. My truck weighs 5200# with me in it according to the scales at Reed Recyclers in Little Rock, AR. It usually gets mid 17's, but if I get on it very much that number goes down in a hurry. FWIW, my '69 C10 swb would get 15mpg with a stockish 461 BBC (RV cam & 650 Holley) when I had it in front of my TKO500 5spd with a .68 5th gear. I tow with my GMC fairly often, and it does okay, but its definitely no big block. As for the 'cool' factor, nothing about a stock plastic engine cover, ugly truck intake, or coil on plug valvecovers from a 5.3 look cool. With that being said, when they are detailed with some aftermarket parts, LS motors can look very nice - 68Stepbed's LS conversion is probably one of the best looking LS motors on this site. This post probably won't help you much, its just my .02 __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!