GM NOS 8998221 Catalytic Converter Fill Plug — 1975–1977 Buick, Chevy, Olds, Pontiac, Cadillac, GMC
type: Unknown Type
Vendor: CorvairFarmer
Description:
GM PART 8998221 — SPECIFICATION & FITMENT CHART
📘 Part Specifications
| Attribute | Details |
|---|---|
| GM Part Number | 8998221 |
| Description | Catalytic Converter Fill Plug |
| Category | Exhaust & Emissions → Catalytic Converter Hardware |
| Material | OEM‑grade metal plug |
| Condition | NOS (New Old Stock) |
| Years Used | 1975–1977 |
| Notes | Used to seal the catalytic converter fill port on early emissions‑era GM vehicles |
🚗 Vehicle Fitment (Verified OEM Coverage)
According to Oldsmobile Obsolete and eBay OEM listings, this plug fits nearly all GM divisions from 1975–1977.
Buick
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1975–1977 — All models
Cadillac
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1975–1977 — All models
Chevrolet
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1975–1977 — All passenger models
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1976 — Corvette
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1975–1977 — Blazer, Jimmy
GMC
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1976–1977 — Sprint
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1975–1977 — Full‑size trucks/SUVs
Oldsmobile
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1975–1977 — All models
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Also listed for 1975–1976 Oldsmobile 455/500ci applications
Pontiac
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1975–1977 — All models
