Ford 221
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Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
They switched from 5 to 6 bolts in '65. In order to switch to a 302 you'd need to change the bellhousing/tranny as well.
Another problem with going to later heads, along with possible valve-to-cylinder interference problems is that the 221 had only 45cc combustion chambers which yielded a compression ratio of 8.7:1. Swap later heads on with bigger chambers and it'll plummet to 8:1 or lower.
I'd leave that 221 alone and swap in an early 5-bolt 289 (not too easy to find these days) if you want to stay with the same tranny/bellhousing, or a 302 with a 6-bolt pattern if you don't mind swapping the tranny out as well. If you have a manual tranny you can still use it by redrilling the 6-bolt bellhousing to the early transmission bolt pattern.
Another problem with going to later heads, along with possible valve-to-cylinder interference problems is that the 221 had only 45cc combustion chambers which yielded a compression ratio of 8.7:1. Swap later heads on with bigger chambers and it'll plummet to 8:1 or lower.
I'd leave that 221 alone and swap in an early 5-bolt 289 (not too easy to find these days) if you want to stay with the same tranny/bellhousing, or a 302 with a 6-bolt pattern if you don't mind swapping the tranny out as well. If you have a manual tranny you can still use it by redrilling the 6-bolt bellhousing to the early transmission bolt pattern.
Last edited by TigerDan; Jan 14, 2006 at 05:35 PM.
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