[Bill Harris]

Well you want to run stock so you can only choose the engines that actually came in a '64 Galaxie 500. The 429/460's have some variants that are excellent, but you can't use them. Unless you have a ton of money and can afford to build a 427, your pretty much stuck with the 352 at 250HP (258HP if you use the Edelbrock heads), or one of two 390 variations, one at 280HP (288HP with ed heads) and the other at 330HP (338 w/ed heads).

The 352 and low horse 390 are virtually identical except for displacement. They have the same heads, same intake, same lift cam and use the same Autolite carburetor. The 390 has a touch more compression, 10:1 instead of 9.3:1 due to less deck. It would probably cost exactly the same amount to build either one, so you would have to decide if the extra 38 cubic inches was worth the extra 30HP factor.

The 390/330HP engine gets you a 600 CFM Holley carb and a little more cam lift (0.439 vs 0.408) but carries a hefty 50HP penalty, which likely is way more than those additions are worth.

You could ask NHRA to take 30 HP off the 390/330 giving it a factored HP of 300 which might be a good combo. 20 HP for the carb and cam are more reasonable.