Since your car is no light weight build the 428 as it will cost the same as the doing such with the 400, then sell the 400 short block to fund the 428 build.
If the heads on the 400 now are not the 4X series and have about a 100 CC chamber then get them fully rebuilt and bowl ported by someone who knows how to do such with Pontiacs .
First and foremost build the short block up strong first by chucking the stock cast rods !
What are the casting numbers on the center exh port of your 400s heads?
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
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