frames will have 2 sets of holes for the mounts up till 87 also so make sure you are hitting the SB holes.

1 set is small block and 2 set is for a BB.

make sure mounts are on correct side of block lugs and biscuts need to turn 90* to line up correct.

sit the engine down on engine brackets without the biscuts to figure out which way the brackets bolt to engine block.

then raise engine install the biscuts.

valve covers are tight at firewall when correct.

IS the trans mount bolted up? if it is pulled forward enough it wont bolt up. the engine mounts are wrong if trans mount is off.

I set the trans mount first, then let the engine down on mounts