The loss in torque between the 5.3 and the 4.8 makes a huge difference. I raced my buddy with a 5 speed 4.8 and pulled on him by a car or two when we hit 90, he drives a manual pretty good too.

 

That is odd, I raced my son twice who had a 5.3 auto RCSB stepside with my 4.8 / 5 speed RCSB fleetside and beat him a couple of car lengths both times.

 

My guess is 15.8.

 

Well I know th 05s come with e-fan but that would be the only difference to your truck he has only 4000 miles on it and he ran 15.28.So you should be some where in the 15.40 to 15.50 range

 

i'd be guessing from a 15.8-16.2. your gain with the exhaust was minimal for the most part and that 3.42 gear is going to kill your times. it may be a good fuel milage gear, but it sure sucks for performance.

 

i havn't been to the track but get consistant 15.0-1-2-3's on g-tech

 

Alright I Have Raced Several 2wd Rcsb 4.8l Trucks With My 5.3 Rcsb Z71. I Out Ran Them By At Least 7 Truck Lengths Up To 90. And This Was Before I Got My Nelson Tune Or My Headers And Exhaust. So I Would Think That You Would Be Around A 16.0 To A 16.2.

 

7-10 truck lengths up to 90mph???

Tell the guys to learn how to drive. There is no way in hell you should have that kind of a lead on a similar truck with the only difference being a 4.8L and a 5.3L.. 7-10 truck lengths is much more than a 1sec difference in 1/4mile ET.

Christ I just relized you're in a Z71 vs 2wd trucks. Sorry but I don't doubt you probably beat these other trucks but you are making a statment like this would be normal. They probably spun the hell out of the tires. LOL

 

When my truck was stock, I ran 1/4=15.91@85.16MPH With an ECLB 2500HD so you should run mid 15's

 

ACTUALLY I SAID 7 BUT ANYWAY JUST STATING THE FACTS! ITS HAPPENED ON MORE THAN A FEW OCCASIONS. I DONT LIE ABOUT CRAP LIKE THAT. I DONT NEED TO.