Matt McD,
I did a similar swap in my '66 c10, swapping a strong, good running stock 230 for a stronger mildly built 292. Easy swap and they both look about the same under the hood - the 292 is a tad bit taller.
Like you I had the 3.73 gears. Suck like crazy on the interstate, topping out at 60-65 max cruising. But with the new 292 I swapped in a 4 speed transmission, with 4th gear having a .73 ratio overdrive. My net final ratio is 2.72, which is even better than those you're seeking. The 3.08 or 3.23 will do you great also. Either will be
much better than the engine killing 3.73 top gear ratio you're running now.
If you go with a higher (numerically lower) geared rear end then I recommend you going with a 2 groove input shaft Saginaw 4 speed. This transmission (in factory settings) will give you a 3.11 first gear, which will still give your 292 great low end torque with the 3.08 rear end.
I have a mild cam, headers with a nice deep sounding two chamber Flowmaster and a 500 cfm 4 barrel on my 292. The muffler has single in and dual outlets, so I have dual pipes out the back. This combo makes
really good torque and power up through about 4000 rpms. I have no problems whatsoever merging with even the fastest traffic on Atlanta interstate entrace ramps. I accelerate almost effortlessly to 70-75 mph in 3rd gear and shift to 4th for easy lower rpm cruising.
I don't see a big personal advantage in going with the v8, though it would have been cheaper to build a similarly powered small block. For my needs this 292 supplies more than enough. Keep in mind that these 292s were used in some huge, heavy C50 & C60 series trucks that not only weighed 8-10,000 lbs, but on top of that were used to haul
heavy loads! And thats a 292 in a restrictive monojet 1 bbl/stock single manifold, low compression piston, small cam form.
Power
only improves when proper enhancements are made in these areas.
-ftyler
