well there is nothing we can do to help , it all comes down the "the guy that told you it was a 143 tooth "
if he is wrong then you will have the wrong flywheel . Is the belhousing factory , iron or alum , aftermarket ?
You should be able to count the bolt holes in your crank to determine if you have a 6 or 8 bolt crank , a "built" Hemi could have either .