You did not specify any info about the heads?
If the heads are alum and have large valves, you may have an issue with valve-to-cylinder interference?
Most alum heads have wider valve spacing than the stock iron heads, and would also use larger valves. Just be sure to check this closely.
For 3.80" bore we would would use a 1.94" intake valve at the most, but usually limit the intake valve to 1.90" for better flow.
A 1.96" or 2.02" intake valve will flow like crazy if you have a 4" bore on a 4.1 block! as it un-shrouds the valve-to-cylinder issue!
Another comment, all TA alum heads are 14 bolt configuration. The SI head can be used with stock rockers, which I prefer over the Chevy Scorpions rockers adapted to a Buick head.