case only difference between BB vs SB 727?

My new 727 has some bolt holes off. Thinking my builder built a BB instead of a SB. Have not had a chance to check things real close but suspect that is the problem. Easiest fix might be to just change the internals to my other case if I can?

I'm not a 727 expert, but I cant think of one part that is not interchangeable. I lifted this off of another web site if you want to verify big or small block:

It's EASY to tell them apart if they're not attached to an engine. Course, I take for granted you can tell a 727 apart from a 904 from the pan. However, big and small block 727s are simple to distunguish. The small block version only has two torque converter dust cover retaining bolt holes across the bottom of the bell housing. The big block version has four. Of course, the bolt patterns are different, but the dust cover bolt holes are an easy fast way to tell.
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Read more: http://forums.moparmusclemagazine.com/70.../#ixzz2iBMbvBn8

Only difference is the case. All parts will swap.

Quickest way to tell is the starter position...

If you are looking at the converter opening with the input shaft facing you, the BB has a starter position around 3 o clock...SB is lower...like 4:30 or 5 o clock...


MB

Also, the mounting bolts for the struts on the SB case require a large diameter hole at 8 and 4 o'clock

i always look at the dowel pin holes. small block is straight across from each other. big block the starter side dowel pin hole is higher than the other side.

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i always look at the dowel pin holes. small block is straight across from each other. big block the starter side dowel pin hole is higher than the other side.

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Ya beat me to it. Also you can measure the distance between dowels openings on the case and measure the dowels in the block.