engine feedback 7.4 vs 8.1

[k30]

Hi all I dont want to start a pi**ing contest here.But because of $$ I'm looking in the 98-02 for a K3500 with a big block.So I'm looking for feedback on the pros and cons of the 7.4 and the later 8.1 engines and vs each other.THANKS

 

[str8axle55]

Never had a 7.4L, but the 8.1L was the balls. I love the old Gen 1 motors, but the LS based one`s run awesome, I`ve had 2 two 6.0L`s and I love them. My D-Max blew them all away. My buddy Brian, 496truck on here has had one since new and loves it. They do like to consume fuel though, like any BB.

 

[k30]

yea I'm not going to care about the MPG I'm just looking for the gas pwr LOL

 

[76zimmer]

I had a 96 3500 7.4 w/ 4.10 gears, I thought that pulled better than the 02 Avalanche w/ 8.1/ 3.73's. The 7.4 got 10mpg pulling 8-9K....the 8.1 got 8.5-9 pulling the same.

 

[k30]

I didn't even know the BB was put into tha AVS.That thing must of gone like a raped ape.I realize different rear ends,Did u notice any difference in pwr ????

 

[76zimmer]

empty you could tell, but the avalanche sucked at towing. I think the shorter wheelbase didn't help any with handling.

 

[DEMON44]

get the 8.1 for sure. over a 7.4l. they go like mad, put a marine tune on it and change the cam, you're looking a 450hp - 500+ftllbs right there. I've got one from an '01, for my '73 Z-28 with a tremec 6pd.

 

[coloradoblazers]

I have an 03 Avy 2500 (3.73 gears). I pulled a 6500# trailer from Cheyenne to Polson, Mt, the truck did well. Most of the time it handeld like there wasn't anything behind it. But, I did only get 8 mpg. I am working on getting the most out of the 8.1 with my diablo sport, i still think there is more power to be found.

 

[noJeepshere]

Hi all I dont want to start a pi**ing contest here.But because of $$ I'm looking in the 98-02 for a K3500 with a big block.So I'm looking for feedback on the pros and cons of the 7.4 and the later 8.1 engines and vs each other.THANKS

I imagine it to be the same way with big blocks, but my 5.7 in my Yukon will get smoked by a 5.3 in a newer Suburban. The injection technology of the gen II Vortecs is so much better at making power then the older stuff. So, along with better tech, the 8.1 is obviously larger. So if power is what you're looking for, look no further than the 8.1. Like what DEMON said, marine tune and a cam and you're in business.

 

[four_by_ken]

As long as you have the ability to work the 8.1l into the engine bay... no contest. The 8.1l is a much better motor.

But, the 7.4l is much easier to retro fit.


The 8.1l new technology is just so nice... from starting to running to tuning to making power. But, cant go wrong with either one.

 

[Avery4jc]

I have an '00 K3500 with the 7.4L and 4.10's with 33's and it tows... well like a big block gasser. I'm not overly thrilled but it gets the job done.

Hindsight being 20/20 I should have bought an older Dodge with the cummins, high mileage or not because it would have been a better tow rig and the mileage would have been much better.
If you're looking at trucks in that year range you can probably afford an older "low" mileage diesel which WOULD be the better choice.


That being said to answer your question I'd go with the 8.1L between the two being discussed. As guys have said the technology is leaps and bounds ahead on the newer gas engines.