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Nailhead V8 and Dynaflow Questions


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1. How reliable are the Nailhead V8s?

2. Are the 425 and 430 V8s found under the hood of 60s Buicks Nailheads?

3. How reliable is the Dynaflow?

4 And last but not least, when did GM cease production of the Dynaflow?

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Reliability -- very good, but a "chunked" timing chaing can cause problems, as with other motors. Once past the Chevrolet designed motors (back when each GM division had their own respective Head Engineer), motors of the higher level GM carlines were usually designed and machined to higher levels of refinement, durability, and performance. Still, maintenance was necessary for long life.

425 would be a Nailhead and the 430 is a newer design.

DynaFlow went through many variations over the years. When properly set up and/or repaired, it was as good as anything else GM did. Seems like there was a Dual-Path DynaFlow for the compact Buick Specials of the early '60s too, that was specific to that car.

DynaFlow production probably diminished with the introduction of the SuperTurbine300 two speed automatic and SuperTurbine400 3 speed automatic (i.e., TurboHydramatic 400, but with Switch Pitch) in the more middle than early 1960s. Probably somewhat coincided with the change to open driveshafts in the full size cars. The Chevrolet TurboGlide was similar in concept to the DynaFlow, but more cheaply designed and was known for lesser reliability than other GM transmissions of the time.

Hope that helps some and I'm sure some others can add to that too. The reason for your curiousity might be???



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To add to the above, the nailhead engines of 322 - 364 - 401 - 425 cubic engines are generally considered to be very smooth, quiet and reliable engines. During the cubic inch and horsepower race of the late '60's, however, the nailhead design had reached the limit of its expandability, and I'm sure that the coming emissions controls were a factor in the decision to replace the nailheads with the 400 - 430 - 455 family of engines in the 1967 model year.

Dynaflow lasted through the 1963 model year on the full-size models and Rivieras. (Buick changed over to an open drive shaft with its 1961 full-size models.) With proper maintenance, the Dynaflow was a very reliable transmission, and I was aware of many Nailhead/Dynaflow Buicks in my hometown area during the 1960's that had traveled 250,000 or more miles, providing relatively trouble-free service. These were excellent cars.

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Guest Reatta1

I have a 66 LeSabre with a 340 engine that gave me nearly 300,000 miles before a broken thermostat caused an overheat that took all the temper out of the rings. Up to that point it never burned oil, never died, and I could waste the 80's genre Corvette's with it. Had a 59 convertible with a dynaflow and was always getting it fixed. Was the worst transmission I ever had the misfortune to have in a car.

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