Bout to take my block tot he machine shop cuz i want 4 bolt splayed caps in my 2 bolt 400 block. Gonna get teh thing align bored and i was curious about something. Yes i did a search already couldnt find anything. Would that not require special main bearings seeing how they are taking material away from the cap side and block side of the main. However i cant seem to find any store (jegs/summit/sdpc) that sells them. Whats the deal with align boreing and bearings fellas. Thanks.

 

The way I understand it, they take material off of the cap and block faces. This creates a kind of football-shaped main journal hole. They then bore the holes round again to the original diameter. You just need to purchase bearings that provide the correct amount of bearing/crank clearance.

Also, the center lines of the crank and cam are now closer together. I think you need to buy a special timing chain set with a shorter chain that compensates for the material removed from the cap/block face.

 

The way I understand it, they take material off of the cap and block faces. This creates a kind of football-shaped main journal hole. They then bore the holes round again to the original diameter. You just need to purchase bearings that provide the correct amount of bearing/journal clearance.

Also, the center lines of the crank and cam are now closer together. I think you need to buy a special timing chain set with a shorter chain that compensates for the material removed from the cap/block face.

 

That depends how much they actually take off. There could be core-shifted factory blocks out there with less cam to crank centerline distance than you'd have after milling the caps.

 

Be aware also that you might need a special main seal depending on how much is taken off. Your machinist should know the part number.

 

Anybody know who sells those bearings?

 

The way my machinest told me was they cut the main cap bolt on then realign. Same bearings

 

lol so who had this actually done before?

 

I've had it done to 4 different 400's. Your not going to need special "bearings" but possibly a special main "seal". The Felpro part number is 2909. It goes for $19.99 through Jegs with their part number being 375-2909. The reason I say "possibly" is if a minimal amount of material is removed, a standard seal will work. Again, your machinist is most qualified to make that call.

 

My block was align honed... no need for special parts or anything. Everything looks great.

 

k thx fellas appreciate it