My 1998 454 is trashed.
For economic reasons, I want to swap in an older big block. EXACTLY what is needed to go from a Gen 6 to Gen 4? I am using a Bravo drive.
Will my L29 heads work on the older block?

Thanks for your input.

I have (2) Mark IV flywheels and starters if you need them for your conversion. Also have new fluiddamper, roller rockers and lifters. I think I still have a 454 Mag fuel pump too. Repost or PM me if you are interested.

Hey Red Dog, I might be interested in your stuff How much are you looking for for these items?

The holes in the alternator bracket may not line up, depends on which heads you end up with the gen 6 brackets use 7/16 bolts in slightly different location then the 3/8 bolts used in MK IV, You can usually drill an offset hole with a drill press in the bracket.

The MK IV sea water pump pully doesn't stick out as far as the Gen 6 by about 1/8-3/16 " so when going from a Mk IV to gen 6 you have to shim the bracket to get the pullies to line up , you are going the other way so this is a problem you may need the mk IV pump

The electric fule pump will work but you will need a block off plate for the fuel pump boss.

The remote oil filter ( the part that connects to the block where an oil filter normally goes) is different you will need one from a MK IV

Flywheel and balancer are different you will need MK IV, the starter motor is ok

I read somewhere about head compatibility when swapping blocks that way... core openings and such. I think it was well covered in Dennis Moore's BB Chevy Marine book. Check it out if you can get your hands on a copy, or I'll dig mine out if you can't. --- Jer

Big Dawg,

PM or call me @ 419-882-1680 with items you are looking for. I have numerous other items for Mark IV. Leave call back # or fax if you get my voicemail.

Thanks!