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Alex V. · 10-16-2016, 01:42 PM

For the 20/30 series trucks w/16" rims (assuming close to stock tires) IMHO 4.10's are the best all-purpose ratio. On my '85 with stock 454/TH400/4.10's, the only reason I'd go down to 3.73's is if I was going to use it primarily for highway towing. Otherwise, 4.10's are a good compromise providing adequate RPM's to accelerate and climb hills in <55 MPH speed limits, but keeping RPM's below 3,000 until around 70 MPH.

10-16-2016, 01:42 PM	#4
Alex V. Registered User Join Date: Mar 2013 Location: Campbellsville, KY Posts: 888	Re: Swapping 4.56 to 3.73 or maybe 4.10 For the 20/30 series trucks w/16" rims (assuming close to stock tires) IMHO 4.10's are the best all-purpose ratio. On my '85 with stock 454/TH400/4.10's, the only reason I'd go down to 3.73's is if I was going to use it primarily for highway towing. Otherwise, 4.10's are a good compromise providing adequate RPM's to accelerate and climb hills in <55 MPH speed limits, but keeping RPM's below 3,000 until around 70 MPH. __________________ Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue.