What was the quarter mile time for 1970 Plymouth Duster with a 198 cubic inch Slant Six engine
Executive summary
Contemporary road tests and retrospective reporting establish clear quarter‑mile figures for the V8 Duster 340 (roughly mid‑ to high‑14 seconds and faster in modified forms), but the specific factory quarter‑mile time for the 1970 Plymouth Duster equipped with the base 198 ci Slant Six is not reported in the provided sources, and no definitive factory‑test ET for that exact combination can be located in this reporting [1] [2] [3].
1. What the sources do show about Duster performance (V‑8 benchmarks)
Multiple period and later sources document quarter‑mile performance for the Duster when fitted with the small‑block V8: Car Life and contemporary test reports put Duster V8 quarter‑mile runs at about 14.72 seconds at roughly 94 mph, a figure repeated by Hemmings citing the March 1970 Car Life test, and echoed across enthusiast sites that summarize factory V8 performance [1] [2] [4]. Retrospectives and databases likewise record low‑ to mid‑14s for stock 340‑equipped cars and much quicker times for special DragPac or heavily modified examples [5] [6] [7].
2. What the sources say about the 198 ci Slant Six itself
Reporting identifies the 198 cubic‑inch Slant Six as the Duster’s base engine in 1970 and lists its rated output in period and later summaries (the 198 is cited at about 125 hp or roughly 110–125 hp depending on the citation and rating standard), with the 225 Slant Six and 318/340 V8s as optional steps up the ladder [3] [4]. Those sources establish the engine’s role and relative economy‑minded positioning but do not publish a factory quarter‑mile ET tied specifically to the 198 Slant Six in a stock 1970 Duster [3] [4].
3. Times for Slant‑six cars in the record are mostly modified or different engines
Where Slant‑six Dusters do appear in performance logs, the runs are either for later modified street/strip projects or for different‑engine cars: a Hot Rod/Car Craft feature about a heavily worked Slant Six Duster reports an eighth‑mile best of 7.18 seconds (a modified build, not factory stock), and forum and enthusiast threads discuss varying ETs achieved only after modifications; those reports cannot be taken as factory standard times for a stock 198‑ci Duster [8]. The collected sources therefore show measured quarter‑mile ETs primarily for V8 cars or for specially prepared slant‑six builds, not a factory‑tested 198‑ci Duster quarter‑mile ET [6] [8].
4. Honest conclusion and research limitation
Based on the supplied reporting, there is no explicit, sourced factory quarter‑mile time for a 1970 Plymouth Duster equipped with the 198 ci Slant Six; the available documented ETs in the sources apply to the V8 Duster 340 (circa 14.7s) or to modified vehicles and drag‑prepared examples [1] [2] [6] [8]. Any numerical estimate for a stock 198‑ci Slant‑six Duster’s quarter mile would move beyond what these sources verify, and therefore cannot be asserted here with sourcing; further archival road‑test material (period Car Life, Motor Trend, or factory performance sheets) or a measured timeslip from an original 198‑equipped Duster would be required to deliver a definitive factory ET.