My recipe for a 289:
289 crank ground to 2.100" on throws to match SBC rod brgs
5.7 SBC rods narrowed to Ford width @ big end full floating at SE ( I beam & liteweight)
Pistons with 1.070" pin height/0.927 pin dia.
AFR 185 heads-paired shaft rockers.
external oil line from filter sandwich block to rear of main gallery to supplement standard oiling.
Stand pipes in cyl head drainbacks to maintain oil level to lower coil of valve springs.
There is a heap of stuff I also do in regard to oiling that is best explained by saying you should be able to pass a 1/2" ball bearing from pickup to filter.
For a 302 swap the SBC rods for SCAT Holden rods and stay at the std SBF rod dia.
For the 289 the Rod Ratio will be 1.98/1, 302 will be 1.87/1.
Remember the comp GT40 cars used 5.315 Indy rods, not 5.155. The longer rod ratios I've suggested have an added benefit with long duration cams like the Le Mans, as the piston dwell time is increased there is reduced reversion during the overlap period as the piston is virtually stopped/ reduced pumping action.
Note for Scott, the pistons with 1.070" pin height are stock shelf items for SBF347 package, the rods are 350 chev items than can be narrowed at B/E very simply on a lathe at minimal cost. Piston cost is not much more than a new set of 289 items and the new rods are cheap insurance over the OE 289 items that have already done a lot of work.