I guys, I'm a Moparts member here on a mission for a good buddy of mine. He has three 63-64 Buick Riv's, one is in a semi resto'd condition, with a 401. At least one of the other two Riv's he has has a Wildcat 445; the 425 engine. Both cars have been sitting, the resto'd one inside and the wildcat outside for 30 years, so the engines are stuck. One of them is going to get rebuilt and warmed up a little. I have a hunch that the cylinders in the 401 are better than the 425. My question is: Can the crank and rods and/or pistons be swapped into the 401 block to make a 425, or is this too much to hope for? Any details on similarities or differences between the two engines would be much appreciated. We have a very reputable engine shop who is going to do the work, but he's never done a nailhead. Thanks
445 is the torque rating on the 401 engine not the 425. The 425 would be listed as 465 on the air cleaner which is its torque rating.
The 401 block won't take a .125 overbore to the 425 size. I've heard that .060 is pushing it. Also the'63 cranks are for the Dynaflow, and the '64s are for the ST 400 trans (Turbo). There is a difference. Good luck, Frank
Mark the bore is the difference between a 401 a 425 so pistons and blocks are not directly interchangeable. Please consider taking it to a shop that has Nailhead experience. I'm sure they can build a killer Mopar or Bowtie but after they ruin you heads by trying to install hardened seats and then install your cam bearings wrong and destroy the rest of the motor they will tell you " We didn't know that" At the very least assembly it yourself and us Nailheaders will be happy to assist you with articles and many years of experience. You can also tap into a wealth of knowledge about Nails over on Yahoos site Nailhead Buick. OK I'm off my soapbox, Welcome to the best Buick board anywhere. :beer
OK, so the Wildcat 445 is actually a 401-so how do I tell if one of the three is a 425? The hardened seats are my idea, tell me how it's wrong for a nailhead. And what's the deal with the cam bearings? This is the sort of stuff I was hoping to find out about.:TU: Illuminate me!:Smarty: Also: if the 445 is a "hot"version of the 401, what are the TQ & HP figures for the standard 401, and the comp. ratio, cam, and carb differences between the two?
The ID number for the engine is stamped on the top front of the block on the surface where the lifter valley pan gasket seals. Toward the pass side is a number that is the engine ID. It will be two letters. First letter designates year (J=63, K=64, L=65, M=66), and second letter designates engine size (R= 401, W= 425 single 4bbl. and X= 425 2-4bbls) There is also another letter for a 401, but I can't remember it right now.
Mark would you have access to a fax machine? I would be happy to fax you about 20 pages on Nailhead motor info. If you do have a fax you can send me the number via private mail on this site. It's a lot of info to try and condense any further. I like you Pacer.
DugSin- no I don't right offhand. Let me see what I can work out. I'd love to have that info. Thanks for the offer and the kind words:TU:
Nailhead info Hi Brian, The 425 would be considered the "hot "engine. It is known as the 465 Wildcat . As for the hardened seats, the Nailhead is known for having a lot more nickel content in it's block making hardened seats un needed(is that a word?). AND it is very easy to hit the water jackets
