6 Cyl: Adequate ?

6 cyl what? The new V6 in the GM is a pretty snotty engine but it needs to be twisted a bit to get the power. With a crew cab I'd probably go with the small 8, Should get as good in the mileage by virtue of lower engine load for the weight.

Per Steve W.:

My Bad.

I am shopping for a used Chevy or GM full crew cab, 5' bed post-2009

Basically looking for the cheapest/earliest one that has side air bags.

I have seen a couple of possibilities - but they have sixes..... Straight or V, dunno.

Can a generalization be made re/a certain group of model years?

Per (PeteCresswell):

To replace my 2005 F-150... so, full-sized 1.5 ton pickup...

It seems that from 2007-2013 Silverados/Sierras only 6 cyl was the

4.3L V-6.

If my own experience with a 1994 GMC Jimmy with that engine is any guide, it should be just fine getting up to 70 mph quick enough. Even in the higher elevations of Colorado.

OK that would be the 4.3 V6. Great engine. BUT not real good in a full sized truck that you intend to use as a TRUCK. They are fine in the smaller trucks or if you intend to run it as a car. You would be working it hard in a full sized truck.

5.3 isn't a bad V8. Be sure tht whatever you look at has been kept up to date recall wise.

Per Steve W.:

Where does "TRUCK" kick in load-wise?

I'm thinking 80% just me and about 100#, but 20% me plus 500# (specifically, towing a small boat/trailer that has a GVW of about 400#)

No altitude involved. The 70 mph merge is the critical factor.

Small boat like that shouldn't be a problem. The 70 mph might be. I'd look and see if you can find one that is close to what you want and test drive it. Best way to tell for sure.

Per (PeteCresswell):

Well, I took a deep breath and went with the 6: 2015 4wd Silverado w/full crew cab and 6.5' bed. .. .. 4.3L IIRC.

Geeze! .. .. Onboard electronics and ergonomics have come a looong way since 2005: imagine..an easily-readable speedo that actually tells the correct speed... And the BlueTooth feature on the radio be da bomb

The diff between this V6 and my F-150's V8 is easily noticeable, but the V6 has gotten us up to 65 mph lane speed on all the on-ramps I have tried so far. ...

The six makes up for the diminished torque with higher RPMs. .... Punch it, and you will see 4,000 just like *that* ... Also, on cruise control, speed will drop sooner/more frequently on slight upgrades; triggering a downshift, 3,000+ RPM, and a few seconds of the lower speed until it catches up.

I am looking forward to finding a relatively-short uphill ramp where right lane speed is 70 MPH. .. .. That will be the acid test.