Will 63 425cid with 2 speed fit with a 400 trans?

[Guest NorwegianRivRoy]

Hi!

Does anyone know if the crank on a 63 425cid with two speed would fit my 64 model 400 trans? Different flywheel, and balancing?

Roy

[TexRiv_63]

Roy,

the experts here have said that the cranks for 63 Dynaflow cars are different than the later ones. They also said there are adapters available to get around that. Do a search on past posts.

[RivNut]

Roy,

In the first place, your '63 doesn't have a two-speed transmission; it's a dynaflow. It has a separate low gear for "sand and snow" but there's not a low driving gear when the transmission lever is in Drive. The transmission works through a series of variable pitch torque converters that will take you from a dead stop to however fast you feel safe driving <span style="font-weight: bold"><span style="font-style: italic">without ever shifting</span></span>. DO NOT manually shift from L to D while accelerating; it's not designed for that, and can damage the transmission.

The 400 transmission will physically bolt on the back of your '63 block, but it ends where it begins. You'll need a different crank or an adapter hub, as Don mentioned, a different flexplate, the torque converter that goes with the transmission/flexplate, the starter (different length drive snout,) the carburetor, and all assorted linkages and switches that operate the kickdown from the donor car. The Dynaflow uses a mechanical kickdown; the ST400 uses an electrical kickdown.

The '64 ST400 is different than the '65/'66 transmissions, the latter has a "switch pitch" feature built into the converter. To make the s/p feature operational, you'll need the wiring harness and switches that are operated by the brake pedal and the carb linkage. After you get the carb and wiring sorted out, you'll need the shifter and linkage from the donor car. 64 or 65/66. The shift pattern for you '63 is PNDLR; for the '64 it's PRNDL; and for '65/66 it's PRND2L. You'll need the neutral safety switch that goes with the shifter. The Buick ST400 is unique and not at all like the Chevrolet or Pontiac/Oldsmobile/Cadillac transmissions from the same years. ONLY the Buick transmission will work. The '64 ST400 is a one year only transmission.

You can't use an adapter to mount a Buick Trans on a Buick motor. The adapters are for the Chevy bell housing; mostly used to adapt 700R4 and/or 200R4 automatic overdrive transmissions to the nailhead. The 700R4 is a Chevy only bellhousing and some 200R4's have a dual Chevy / BOP bolt pattern.

The consoles which housed the ST400's are somewhat different as well. The '64 can be made to work on a '63, but if your donor trans came from a '65, you'll need a '65 console, it's longer where the shifter lever is. They also bolt to the car differently. If your trans came from a column shift car, you're going to have to find another donor vehicle for some of these parts.

Ask yourself why you want an ST400 and make sure it's worth the task and $$$ you're in for. The dynaflow you have is a really rugged transmission. What other automatic transmission can you think of that you can push start? It's the ideal transmission for cruisin'.

Ed

[Guest NorwegianRivRoy]

Hi!

Thank you so much! I have a 64 Riviera with a 425 and the 400 trans. But the engine is tired, but the transmission was overhauled not long ago. And I found a 63 425 with the dynaflow on ebay. But since it seems like a lot of trouble, I'll wait and see if I can find another engine, or engine block with the correct flywheel and crank!

Thank you again, you've been most helpful. Not too many rivnuts around here in Norway...so I really appreciate all help and tips from you guys in the US!

Keep them old Buicks running!

74 Apollo

64 Riviera

58 Special

58 Super

[RivNut]

Roy,

You might want to consider overhauling the engine in the '64. It might be less expensive and would be more rewarding in the long run. You'd always know what you had, and you'd have a car with matching numbers.

Ed

[Guest NorwegianRivRoy]

Yes. Normally it would be the best thing to do. The engine was rebuilt under two years ago, except for crank, pistons, rods and cam. The engine block cracked open behind the starter, along the cooling canal. Had it welded at a professional company, and it turned out ok. But several things are still difficult. It still leaks a lot of oil, it shakes like a bad tuned motor, only it is not! I installed a MSD electronic ignition on it, with brand new distributor and all... Still shakin'!!

And many earlier owners ran the engine hot, and it's been known to eat waterpumps.. Many have been working (more or less) on this engine the last 20 years.. Think it has been screwed over to much.. :-)

Thanks

[RivNut]

Sorry to hear that so many hands have made an attempt to get the motor right. The nailhead is balanced by a combination of internal and external components. Unless you have a broken piston or some weight has come off something internally, you might look externally for your shake. Two things come to mind. The first, which would be the easiest to do wrong would be to install the flex plate incorrectly. There are six evenly spaced mounting holes on the flex plate that line up with the hub on the crank. There are six ways to bolt it on, but only one correct way. There's a seventh hole on the flex plate that has to be aligned with a divot in the crank hub. The weights on the flex plate are used to help balance the rotating assembly. The second, which can happen but is somewhat rare, is that the outer ring on your harmonic balancer on the front has slipped. That would be easy to check. Borrow the balancer from the '64 and swap it out. See if that helps. I doubt if the distributor has anything to do with your shake. Is it constant or only at certain RPM's?

Keep digging, you'll solve it.

Ed

[Guest NorwegianRivRoy]

It shakes at all rpm's, but of course mostly noticeable at low rpm's. The flexplate is installed correctly, but it had a damage so I'm looking for a new one. I will check the harmonic balancer to rule that out..

Will let you know what I find out! Thank You so far!!!!

[Guest NorwegianRivRoy]

My block has the number B1364704, and I found an engine with the code B1364705. according to buick.net (http://www.buicks.net/shop/reference/nailhead_casting_numbers.html) My engine is 63-66 425, and the parts engine is 64-66 401/425. Are these interchangeable?

[RivNut]

Roy,

The same casting number can be machined for different applications. They shouldn't really be used for identification purposes. You need to find the stamped numbers on the block. This link will give you some better clues as to identifying what you have.

http://www.buicks.net/shop/reference/engine_ident_where.html

Read the article on 425's from the same website, it will give you specific details that will help you identify the 425.

You need to verify that the "production code" numbers have a W in them. W is the designator for a 425; T is the designator for a 401. The other letter in the code is the year code. J= '63, K='64, and M='66. JW is a '63 425; KW is a '64 425.

All you basically need to make a '63 and '64 interchangable is to use the crankshaft and starter that goes with the transmission.

Ed

[Guest NorwegianRivRoy]

Thank you Ed!

Have a nice day!

[Guest NorwegianRivRoy]

Thank You all for all help! I'm happy to say your advice paid off...I got the engine and trans repaird, at a fairly low cost. And now it runs stronger than ever, with no noises or any leaks! Thanks again!