nailhead questions

Hello fellow Buick owners! I recently bought a 57' Special which I'm intending turn into a mild street rod (luv the look). I'm resisting the "easy" route (ala bowtie bb) and have decided that she must be nailhead powered. Of course, she comes stock with 364 nh. What I'm wondering is, which nailhead should I do? 425? Any particular year, or out of any particular car... What's the difference in the blocks? (Of course I know the bore is bigger, but SURELY the block had to change to accept the bigger bore... right?). I'm looking to have a fun, relatively quick (as quick as 4400 lbs. can reasonably be) car that will be both reliable and respectable. Nothing too radical, but not something that will get spanked by the first small block Chevy powered Belair she sees. So, what nailhead would you do up, and what would you put in/on it in terms of intake, carb, cam, etc.. Also, if anybody needs any 364 stuff (or 57 stuff) I just bought another 57 as a donor car. Fall Carlisle (PA) is coming up so it'd be nice to have a plan of action. Thanks so much for any help or suggestions you might have. BTW, I know it's going to be a little expensive, but it damn sure will be cool to be a nailhead!
Tim

 

FWIW, go with a 425 from a '64-'66 Riviera, add either a 2-4bbl factory manofold, or better yet, one of those vintage fifties 3x2 offenhauser intakes! Headers shouldn't be a problem, T/A Performance makes them for the 425. Finally, kudos on sticking with the high torque nailhead in your '57, it's the perfect motor to get that hunk of iron movin'!

 

425's are rather rare and quite pricey compared with the 401". I went with the 401 with an Offy 2x4 intake & two 500cfm Carter AFB's in my '55 Special. I installed a cam from Poston and a 4-speed and I'm very pleased with the whole package.

There were basically three different nailheads, dimensionally-wise: The 264" / 322"; the 364"; and the 401" / 425". Lots more stuff around to hop up the 401" / 425" mills, than the other nailheads, but nothing like SBC's.

I think you'll be really pleased with the nailhead engine instead of something else. :TU:

-Bob

 

Engine

The 1963 425 and the 1959-1963 401 will bolt right up to your 57 Dynaflow. Both engines would be nice with a good rear gear ratio (3.42 or so), and some upgrades as discussed above. The last of the Dynaflows were not that bad when adjusted properly and in good working order! Make sure to keep the engine torque in the low rpm range where it is not too far from the transmission stall rpm of the torque converter. Otherwise, the combination will fall flat on its nose from converter stall rpm to the beginning of the torque range of the engine.

Another option is to increase the Dynaflow transmission converter stall rpm so that it is closer to the torque range of the engine. I would not know where to tell you to send a Dynaflow transmission converter to be modified. The Nailhead is rpm challenged because of the limited air-flow through the heads. Keep in mind that increasing the transmission converter stall rpm will eliminate some usable rpm and the engine will approach the upper rpm limit that much sooner. Good luck with it, and keep us informed of your progress.

Cheryl