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Discussion Starter #1
I installed the real main seal it was 2 piece seal and after installing it’s still leaking oil. Can someone help me with what seal is the correct one for pictures below engine. Thank you
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Dunno, 1980 block tho.
 

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What crank are you running? Maybe you got mismatch with a 2pc block with a 1pc crank.
 

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Looking at the pic of the back of your block that block uses a one piece seal. Had good luck with national brand rear main seal's part #3909. Will be the same seal as late model 302 5.0 from 1986-2001 as well.
 

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Discussion Starter #5
Looking at the pic of the back of your block that block uses a one piece seal. Had good luck with national brand rear main seal's part #3909. Will be the same seal as late model 302 5.0 from 1986-2001 as well.
Perfect thank you
 

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Ok hold on. There is no way to install a 2 piece seal in a 1 piece block. So if you already took out and put in a 2 piece seal, then buying a 1 piece is going to make you sad.
 

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What crank are you running? Maybe you got mismatch with a 2pc block with a 1pc crank.
The rear hub of the 302 crank where the main seal rides is the same diameter on early and late model 302. Couple differences in the early model cranks compared to late model the early model had oil slingers in the rear by the seal and were 28 oz balance. You can run a late model crank in an early model block and vise versa I have an 87' 302 crank in a 68' 302 block currently in my 89' notch even without an oil slinger no leaks with properly installed 2 piece seal. There may be miss information about a 1980 block rear main seal that had to be close to a transitional year when they went from 2 piece rear main seals to one piece seal machined blocks. Thank goodness ford changed to one piece.
 

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I can tell from the pic of the back of this 1980 block that it uses a 1 piece rear main seal. The clearances on the back of a 2 piece seal block and rear main cap to crank hub are extremely tight only about 0.0625
 
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