I have one of each!! Sub 7.4 & X V10. Talk aboot having stock in the oil companies!!
Have had the X for 3 mos now, the jury is still out on how it will do as my tow vehicle. Has 94K miles, approx 50K on the motor. Been dialing in the Dual Cam, think I have it pretty close now. Still has some wander, but feels close to the Suburban. The Excursion seems to be a bit more powerful, and thirstier!! Pulls the hills a bit better than the 7.4 does, esp at higher altitudes. Trans does shift up and down a bit more than the Sub.
Hard to say (for me) which has the advantage. Many differences. Suburban is a better veh in everyday use, gets somewhat better all around mileage. Ride is better, except over speed bumps. Almost as much room as the X, not enough difference that I can complain about it. Brakes are better on the X, great pedal feel and response. Sub turns tighter, feels smaller, although they are within 200# of each other scale wts.
The Suburban has 128K on it, and has not had any of the problems that have been mentioned by others. Only major work I have done is intake gaskets. A/C works great, haven't had to service it at all. X's rear system is out due to bad line to the rear. Plugged rear system off, and it keeps up pretty well in 90+ deg heat so far this spring. Very expensive repair, but probably the same with the Sub. BTW, the 7.4's did not have a tow/haul switch. AND they do drop out of lockup easily. At higher altitudes, on a good hill, I will see 240-260 deg for trans temp. Gauge is reading the output line to the trans cooler. The X on the last trip up same drive hit 220 deg (read on a phone with Torque app), and did stay locked up longer at lower speeds.
But I digress, and will shut up!! If you can find a 7.4L Suburban in the 98-99 range without excessive miles, I think it would do you fine.
