About a year ago I purchased a 1969 Mach 1 428 SCJ, R code with drag pack, 4.30 traction lock rear end, close ratio top loader 4 speed. It has been in a garage undriven since 1982.
Unfortunately the the owner took out the original 428 block and replaced it with
a 1971 427 side oiler service block. He did reuse the heads and crankshaft.
My questions are: Should I replace the 427 block with another 428? What would add the most value to the car?

 

For some, a 'matching' block built the same time as the original.