Towing with a small block

[kwmech]

So my 91 Suburban has the anemic 350 TBI engine with about 160k on the clock. I've done gearing upgrades along with swapping to 1 ton axles and 4.56 gearing, along with that is going to a 4l80e with a stand alone controller. Was thinking of going with a stroker kit. I see locally somebody selling a 94 suburban with a 454. It would totally bolt into my squarebody and all the parts are there for the conversion aside from having the exhaust cleaned up. 454 has about 50k on it while the whole 94 burb has 180k on it. Don't know the specs off hand on the 94 big block, but I know I'll get probably twice the amount of torque I need, but the mileage may really fall off. However at the same time the mileage on the 350 isn't all that great toting this aerodynamic brick around with another brick behind it. Thoughts?? An Ls conversion is really not in the cards being california and smog nazis I'd have to deal with.

[mongocanfly]

My C30 had a 350 in it, it could barely get out of its own way..
I started looking at engine upgrades,
Kinda wanted a dmax, thought about a BB,
I like their torque numbers and where they hit
But at that time a dmax was a very expensive swap,
and I couldn't find a BB,all the dragracers were hoarding those.
So I went LS..even with the numbers it puts out,sometimes it leaves a little to be desired..
But I pull some hefty loads with it, and when I do the mpgs don't exist..
I think you'd be happy with the BB..except at the pump..

[kwmech]

I get that as my flatbed has a 454 along with my longhorn. The Suburban gets about 12 when I'm towing and going easy on it. I'm think the BB won't be that much of a change mileage wise since it won't be working all that hard to accomplish the same thing. The complimentary drivetrain is already there, they're both TBI. 94 suburban is 3000.00. I'm thinking I can yank the engine and part the rest of it out and get my money back. Just what I need is another project to take on this year.

[chris989]

Originally Posted by kwmech

So my 91 Suburban has the anemic 350 TBI engine with about 160k on the clock. I've done gearing upgrades along with swapping to 1 ton axles and 4.56 gearing, along with that is going to a 4l80e with a stand alone controller. Was thinking of going with a stroker kit. I see locally somebody selling a 94 suburban with a 454. It would totally bolt into my squarebody and all the parts are there for the conversion aside from having the exhaust cleaned up. 454 has about 50k on it while the whole 94 burb has 180k on it. Don't know the specs off hand on the 94 big block, but I know I'll get probably twice the amount of torque I need, but the mileage may really fall off. However at the same time the mileage on the 350 isn't all that great toting this aerodynamic brick around with another brick behind it. Thoughts?? An Ls conversion is really not in the cards being california and smog nazis I'd have to deal with.

What weight and windage?

I have an 89 v2500 with 456 gears, 4l80 and 37s. Tows great with 4500 pounds,, Used to tow 8500 and it was a bit much on hills.

I run a small lunati cam and edlebrock intake, No major mods.. I get 12 mph in town and over 15 on the highway. ~11 towing

Chris

[THI]

I know this is an old thread, but I thought I would add my experience. I had a 1988 V20 Suburban with a 350 TBI/TH400/4.10 combo - got 12 MPG empty or towing. My next Suburban was a 1992 K2500 with 454 TBI/4L80E/3.73 combo - got 16 MPG empty on the highway and 13 MPG towing about 6,000# in Drive. My 1996 K2500 Suburban with the 454 Vortec/4L80E/3.73 would get 15 MPH empty and 13 MPG towing 6,000#. Bump that up to 10,000# towing and it would get 11 MPG (and you knew you had 10,000# on the hitch! My old 1988 really did not like to tow more than 6,000# with the 350 and I always wanted to replace it with a 454 from the day I bought it!

[chewychevy67]

If you can get an 8.1. Of all the gas trucks I've ever towed with I like it the best. I like it so much that I haven't replaced it with a new truck yet. Not nice at the pump either though.

[OutlawDrifter]

Originally Posted by THI

My 1996 K2500 Suburban with the 454 Vortec/4L80E/3.73 would get 15 MPH empty and 13 MPG towing 6,000#. Bump that up to 10,000# towing and it would get 11 MPG (and you knew you had 10,000# on the hitch!

I have a 1999 K2500 Suburban with the Vortec 7.4l 454(4.10 gears). It has upgraded 5.0 Motorsports injectors, Black Bear tuned ECU, and the exhaust has been opened up. On HT tires, I've never gotten close to 15mpg empty at actual highway speeds. I managed 14mpg on one trip @ 68mph, filled up at the same pump at the same station in the morning and that night when I got home, hand calculated mileage.

Towing is usually 11mpg or less.

Would I trade the big block for a small block...never. I didn't buy a 3/4t Suburban for mileage, I bought it for comfort, capability, and for the bulletproof parts it came with.