Bearing help

[sprint3]

Cleaning out the shop and came upon a box of main bearings..they are new...top of box was marked 400sb ..but the end says ms829p BBC? I looked at the bearings and they are:5203 upper and 5202 lower. Rear main numbers are:6431 and 6432..the box says michigan 77 made in england...what the heck are these? Thanks!

[markdunlap]

BBC "P" production main bearings. Same as Clevitte bacically. Good for stock, mild performance rebuild. "H" is for high performance.

Tape them together in a circle and measure ID. Should be 2.750" approx.

SBC 400 is MS-1038. ID is 2.650" approx.