Rear End Gears Swap
Short answer: Swapping gears to switch between “highway” and “around-town” ratios is possible but impractical — a proper gear change needs skill (setting backlash and tooth contact), special tools (dial indicator), and time (~$250 gears + $100 tools, or ~$250 shop labor; a weekend the first time). For two ratios, a second complete rear end (faster to swap) or an overdrive transmission makes far more sense.
- Overdrive route: a 200-4R (auto) or T5/Tremec (manual) lowers highway rpm — more up front, but cheaper than several gear changes. Another member’s trick: a taller tire on a spare set of wheels for road trips.
- Rear-end interchange: first-gens use an 8.20″ 10-bolt unique to Pontiac/Buick (a corporate Chevy 8.20’s gears won’t interchange). From 1970, GM went to one 8.50″ 10-bolt (Nova/Apollo/Omega/Ventura ’70–74 and 2nd-gen F-bodies) — tall gears are plentiful there; it fits with relocated spring perches and a unique rear U-joint.
- Beware: other 10-bolts (7.50″ late-’70s/’80s, 8.875″ trucks) exist — know exactly what gearset you’re buying. And correct your speedo gear after any change.
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Content last modified: June 13, 2026 at 10:06 am
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