Each engine family has a different torque range. The 3.38s with an OD may be OK for a 283's torque range but it aint gonna work with a 248 six and I'd bet not for a 235 either. With 3.90s my 248 rpm is well below the power band at highway cruising speed. If it had any higher I couldn't use OD.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.