I owned one: 1962 "Metro-mite," early 70s in Tidewater VA. With the 152" engine & ****er 3-on-the-floor, it lacked the low-end to climb some driveways but got a bit short-of-breath just above 50 MPH. I have seen one of that gen of IHC Metro-mite with a SBC shoehorned-in. In that narrow a body it crowded the driver badly. "Life-happened" to my 1962 between the Navy & Tidewater's *other* growth-industry; had to choose between moving-expenses & paying its ransom. FWIW another one I saw had a Chevy I-six (radical surgery for drivetrain & floor but no bite out of the driver's space). Best regards, all.
Most of my first ~1½ years of driving experience was in my Dad's '64 Scout-80 4x4. That little 152" engine as I remember it was a bit cranky to start and peaky. I cheated with the hubs disengaged & 1 end of the rear axle on a jackstand in HS auto-shop, to record where 4000 RPM was on the speedometer, using a dwell-tach. No mishaps occurred, but "DO NOT TRY THIS AT HOME." I had read (in the manual) the *recommended* redline was 4000, though a data-plate in the engine bay gave the HP as 88 at 4400. The numbers I recorded (for 4000) thus were: in low-range, 8, 15, & 30 MPH; in high-range, 12, 40, and [not-even-happening, but in-theory] 80 MPH. One definition of insanity in the MT Rockies woulda been finding a steep enough road to hit 80 MPH (on OE 600-16s) in a 1st-gen IHC Scout in 1968. But, with that info I obtained, I recall the Scout had useful torque between 2000 & 4000 RPM & had nothing the reasonable person might mistake for acceleration, much below 2000 RPM. Best regards, all.
When I worked at the local IHC dealer in the early 70's we serviced a few scouts with the turbo 4cly. You had to cut a hole in the p***enger floorboard/fire wall area to access the rear spark plug.. or pull the turbo. The few I saw all had the hole cut with a screwed on patch covering them. Not very powerful if I remember right.
we had one on the farm , not a pulling vehicle like the big harvester trucks , but for around farm and to town it suited its purpose ( and better than riding a horse in the snow and cars don't cut it when you have drifts 1-3' high ) .