Thread: 425->455
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Old 04-18-2007, 06:41 PM   #5 (permalink)
joe_padavano
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Quote:
Originally Posted by 66starfire View Post
Ok since I wasnt sure on this i have heard rumours. do the 455's have 2 different size lifters and bank angles?? I have from what the guy told me, a 1970 out of a olds 88.
but I was thinking of a performance motor for my starfire, and thought about the stronger factory 425 crank/rods.
455s all have a 39 degree bank angle and 0.842" lifters.

425s could have come with either 39 or 45 degree bank angle and either 0.842" or 0.921" lifter diameter.

A 66 Starfire 425 SHOULD have a 45 deg bank angle and 0.842" lifters, but be sure to check.

If you do plan to swap parts between the 425 and 455, be aware that despite the common bore, the pistons are different. The 425 uses 7" rods; the longer stroke of the 455 requires 6.7" rods. The pistons have a different compression height as a result.
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