73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Orlando87Chevy on August 02, 2012, 06:16:40 pm
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I thought I got lucky today. I bought myself a 454 in excellent condition today for $500. What a steal. When I checked the casting numbers it came up a 1991 454 with a Gen 5 block. I heard that you can't swap the Gen 4 heads to the Gen 5. Is this correct?
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You can use Mark IV heads on a V block but you have to use special head gaskets, voodoo and be very careful. It's not a bad motor, you just need to read up on it and learn about the differences.
Does the block use a 1 pc or 2 pc rear main? 2 pc is Mark IV, 1 pc is Mark V or VI.
Btw, Mark V = no mechanical fuel pump boss, electric only.
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I looked up the casting number and it was an 1991 4 bolt main. Who makes the special gasket?
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A quick Google search yielded this, check out post #4 -
http://www.chevelles.com/forums/showthread.php?t=19073