Hi. I have a 69 Firebird HO with 4-speed Muncie, block code WN. I had to have the engine rebuilt and the the shop found that the crank was wobbling due to poor prior engine rebuild. They said the block can't be rebuilt due to excessive wear. I located on-line a same year HO block but it was from a automatic car, block code XC. A buddy of mine who has a 69 Camaro said the block from the automatic can't be used with a standard tranny due to the need for a clutch bracket assembly requirement which needs the correct bolt holes in the block. Are the Pontiac engine blocks also the same and need special holes for the pivot bracket, etc? I really want to keep this car as close to original as possible and use the same block casting number (both the XC and WN blocks have same casting number. Thanks. John
Before you get rid of ther original block I think I would change the motor and keep the o.e. block and ask around to see if there is a poss. fix for this with today's tech. I 'm sure someone has run across this nefore and has a fix for it.
Keeping the o.e. block to put in later would make the car worth alot more $$
I think I would call Butler or Kauffman and ask them.
Doug, thanks for the advice. I was planning to keep the block as I really want this car to be as original as possible. I was told by the person whom I bought it from (he worked for GM in MI), said there were not many 350HO's made with 4-Speeds as the 3-Speed was more typical. Interior, floors, frame rails and trunk are mint with only the quarters needing to be replaced. He also indicated that it might have the Royal Bobcat package as there are Royal decals on both rear windows.
The only way to prove a Royal Bobcat is with supporting documentation. And Royal Pontiac offered "Bobcat" kits that were over the counter accessory packages that were owner-installed as well, and don't have the same panache as a Royal-built Bobcat.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
The BLOCKS are the same between the two tranny types, but the crank shafts MAY be different. Luckily, this difference is easy to fix.
Some automatic crankshafts were not finish bored for the pilot bearing / bushing. You would be ahead of the game to seek out a pilot bearing (still available from GM) instead of the bushing and have the crank checked to make sure the bore for the bearing is finished. The machine shop will need the bearing in order to bore the crank correctly. If memory serves, it's a 35mm O.D. bearing, but definitely check it.
For obvious reasons, this has to be done before the crank is put back into the block.
