Engine Code Automatic & Manual - difference

[dixon5553]

what is the difference between an engine with a code for an automatic trans vs manual trans.

For example a 1965 110 automatic has a RH or RX code while the manual trans 110 engine as a RD code - what exactly is different with the engine between the two types of transmissions?

[Wagon Master]

Distributor internals and vacuum advance canister. Creating a differant advance curve. I believe carb. internals changed slightly also.

[RexJohnson]

As said the dist could be different but I believe with the 110 they both used the same 319 dist. Carbs can be also be but things like the bell house are also include in the code.

[bbodie52]

Depending on the model year and horsepower rating, some Powerglide engines had a different compression ratio (based on the cylinder head combustion chamber). Also, I believe that some Powerglide engines had a different camshaft or camshaft timing in support of the optimum configuration for an automatic transmission.

The attached documents may be of some help in breaking down the various engine, carburetor and distributor configurations.

[66vairguy]

As said the dist could be different but I believe with the 110 they both used the same 319 dist. Carbs can be also be but things like the bell house are also include in the code.

Yes the 65-66 110HP used the same distributor.

The engine code two letter suffix was to indicate one or more things were different from other engines.

The 140HP for the 4 spd. Monza vs. the Corsa is an example of the only one difference - the vacuum tube fitting for the vacuum gauge on the Corsa. However the 140HP with a powerglide had a number of differences including a unique crankshaft (gear).

What gets confusing is when the two letter suffix is used on two different engines on different years!!!

The other issue is some swap parts (heads, etc.) on to different engines so the suffix code means little.

[RexJohnson]

There would be several differences between a Corsa 140 or a non Corsa 140. As said the balance tube, the thermistor with the mini harness and the heater shroud for the wire to come out thru with grommet. Also the mini harness for the oil pressure and temp switch would be different.

[joelsplace]

The 80HP engine had more compression and 84HP behind an automatic.
Obviously the bellhousing. No pilot bushing and with flexplate on the auto.

[66vairguy]

There would be several differences between a Corsa 140 or a non Corsa 140. As said the balance tube, the thermistor with the mini harness and the heater shroud for the wire to come out thru with grommet. Also the mini harness for the oil pressure and temp switch would be different.

I stand corrected!! Thanks Rex, I forgot about no temperature gauge and associated changes on the Monza. Yes the same switches for oil and temp, but I didn't know the Monza140HP did not have the "dual path" engine harness to allow use of the overtemp buzzer.

I've read the 66 Corsa only used the overtemp buzzer on turbo engine, not the Corsa with140HP engine. What say you?

[RexJohnson]

Everything except the buzzer was there, that way you didn't have 2 different Corsa wiring harnesses. Turbo or 140, that would have been costly and confusing.