255 V8
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From: Dublin USA
255 V8
Someone tell me something about the 255 V8. How do you i.d. it? I am told it looks like a 302. Are parts interchangeable? I think it came out for a couple of years from '80 to '81. Is that right? Any info would be appreciated.
Garyr
Garyr
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255 V8
A 255 or 4.2L is a debored 302 design. It's stroke is still the same as a 302 but the bore is reduced from 4" to 3.68". Apparently some iron was removed from the block to make them lighter. The heads have smaller Intake valves than 302 heads, but as long as you pay attention to compression ratio issues, you should be able to put 302 heads on a 255. I believe bolt on stuff like the water pump and oilpan, manifolds should interchange w/ 289,302 stuff. The casting numbers I have listed for the block and the heads are: EOSE-AE for the block and EOSE-AC for the heads, the heads have 55.4cc combustion chamber w/ 1.67intake and 1.45 exhaust valve sizes.
BBT
BBT
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From: Dublin USA
255 V8
Thanks BigBrownTruck
Now I have some checking to do. I wonder if a crank from a 302 and the flywheel and harm.bal. would mess this engine up? Got a vibration I can't figure out and I'm sure it's a 302.
Garyr
Now I have some checking to do. I wonder if a crank from a 302 and the flywheel and harm.bal. would mess this engine up? Got a vibration I can't figure out and I'm sure it's a 302.
Garyr
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Joined: Aug 1999
Posts: 910
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255 V8
You know if you were to put the balancer and/or flexplate-flywheel from an older 302 (pre82) on a newer 5L (post 82) or vice versa, you'd have a vibration problem. I know of a person who bought a replacement shortblock for his 79, put his externals on it and had a bad vibration. Turns out he was sold a later model 5.0L. When he put the proper balancer and flexplate on it the vibration went away.
BBT
BBT
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