Carburetor – Converting From 2 BBl to 4BBL
Short answer: Converting a 1968 2-bbl to an Edelbrock Performer 4-bbl is straightforward; the fiddly parts are the throttle linkage/cable, the fuel line, and the vacuum connections.
- Throttle linkage: the stock cable won’t reach — use an aftermarket bracket (Edelbrock lists linkage accessories) to bring the cable closer, and fabricate a kickdown-switch mount from your 2-bbl parts if needed.
- Fuel line: Edelbrock fuel-line kit #8135 (hose, fittings, filter, clamps), plus a banjo fitting #8089 for low-profile air-cleaner clearance. No hard-line kits — make your own if you want hard line. Route rubber line away from heat.
- Vacuum: if the manifold has no vacuum fitting, the carb has three ports — the large center port at the base is PCV (keep it connected), a smaller full-time (manifold) vacuum port, and a ported (part-time) port. Most distributors use ported, but verify which yours needs, and cap any unused port.
- Valve-cover breather tube: either cap the valve-cover opening with a breather, or knock out the plug in the aftermarket air cleaner and route the hose there (a stock 4-bbl cleaner uses the hose as original).
- Air cleaner: any 4-bbl cleaner fits if the neck matches — pick one with the inlet on the correct side and not too tall (close the hood slowly to check).
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Content last modified: June 13, 2026 at 10:06 am
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