Bullnose Bill Answer
by Ed

Can I use the 302 2bbl flex plate when swapping a rebuilt 1985 351W 4bbl into my 1983 F-150 with a rebuilt C6?

Bullnose Bill explaining flex plate and torque converter fit for a 1983 F-150 351W swap

This Q&A session is powered by Bullnose Bill, Bullnose Garage’s advanced AI mechanic.
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Bill says:

Great question! When swapping from a 302 to a 351W in your 1983 F-150, you need to pay attention to the imbalance of the engines. The original 302 uses a 50 oz-in imbalance, whereas the 351W uses a 28 oz-in imbalance. This means you’ll need a different flexplate for the 351W.

Flexplate Considerations

  1. Imbalance:

    • 302: 50 oz-in
    • 351W: 28 oz-in

  2. Tooth Count:

    • Both the 302 and 351W commonly use a 164-tooth flexplate for the C6 transmission.

  3. Crankshaft Bolt Pattern:

    • Ensure the flexplate matches the bolt pattern of the 351W crankshaft.

What You Need

  • 28 oz-in Imbalance Flexplate: Make sure it has the 164-tooth count for compatibility with your C6 transmission.

Pro Tips

  • Check Starter Engagement: After installing the new flexplate, verify proper starter engagement to prevent future issues.
  • Torque Converter Compatibility: Ensure the flexplate’s bolt pattern matches your torque converter.

Installation Advice

  • Torque Specifications: Use a torque wrench to secure the flexplate bolts to the manufacturer’s specifications to avoid vibration issues.

If you want more detailed guidance, there may be a video on the Bullnose Garage YouTube channel that covers flexplate swaps.

Got any other questions about your Bullnose?

User avatar

User:

Which torque converter fits a rebuilt 1985 351W 4bbl in my 1983 F-150 with a rebuilt C6—will the 302 2bbl converter work?

Bill avatar

Bill:

When swapping from a 302 to a 351W, you can generally use the original torque converter from your C6 transmission. Here’s a rundown:

Torque Converter Considerations

  1. Bolt Pattern:

    • Ensure the flexplate bolt pattern matches your existing torque converter. Most C6 converters will work, but double-check fitment.

  2. Stall Speed:

    • If you’re keeping the truck mostly stock with 3.50 gears, the original converter’s stall speed should be fine. If you plan on performance upgrades, you might want a higher stall converter.

  3. Condition:

    • Inspect your torque converter for wear or damage. Consider rebuilding or replacing it if it’s seen better days.

Installation Tips

  • Drain and Flush: Make sure to drain and flush the torque converter and transmission cooler to avoid contamination.
  • Alignment: Properly align the torque converter to the transmission pump to prevent damage.

Pro Tips

  • Converter Size: Most C6 converters are similar, but verify size and bolt pattern to ensure compatibility with the new flexplate.
  • Upgrade Considerations: If the engine rebuild includes performance upgrades, consider a torque converter with a suitable stall speed.

If you need more specifics, there might be a relevant discussion on the Bullnose Ford subreddit or a video on the Bullnose Garage channel.

Let me know if there’s anything else on your mind!

This answer was written by Bullnose Bill, our AI shophand trained on hundreds of Bullnose-era Ford topics. He knows his way around old Ford Trucks.

As with all of Bill’s answers, it has been reviewed and approved by Ed Zenisek, the man behind Bullnose Garage and a real human being.

While we do our best to keep things accurate, always double-check any repair advice and use proper safety procedures. For real-world walkthroughs and more hands-on content, check out Bullnose Garage on YouTube or visit the BullnoseFord SubReddit.

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