Best Features of Early and Late Model Engines

When rebuilding an engine, we usually attempt to adhere (faithfully) to either a completely late model, or a completely early model configuration.  However, having long admired certain features of both models, I have always wanted to build up an engine which incorporated the best features of both engines.

We were recently given such an opportunity by a gentleman who needed an engine for a vintage Hinckley sailboat (circa 1946), which he had been reconstructing for several years.  Since he didn’t have an engine to rebuild (or exchange), we decided to use the collection of early and late model parts we had been saving for such a purpose.

QUALITY FROM THE 1960’S

We started with a basic early model engine (from a late 60’s Pearson Vanguard).  While all water jacketed castings on the Atomic 4 fleet were manufactured with a corrosion-resistant alloy, it has been our experience that quality control was a bit better in the sixties than in the later years.

The block, head, and manifold on this engine were virtually free of corrosion, even though the boat had spent most of its life on our hot and salty Chesapeake Bay!

LATE MODEL IGNITION WINS OUT

We chose a late model (Delco) distributor, since we find the points and condenser somewhat easier to service than in the Prestolite.  There are two items to consider in making this choice: (1) a 5/16" hole must be drilled and tapped in the aft housing just behind the distributor for the bolt of the hold-down bracket, and (2) a late model water jacket side plate will need to be used, since the Delco distributor contacts the early model side plate.

The late model dip stick can also be seen on this view .  These dip sticks have simple "low and full" marks which are much easier to use than the earlier model sticks with confusing small holes and numbers.

While we find the small oil fill lid of the early model a bit slow and hard to use, we couldn’t bring ourselves to do without the classy early model reversing gear cover!  This view of the engine also shows the later model Oberdorfer (flexible impeller) water pump.

MORE LATE MODEL ELECTRONICS

This view of the engine shows the late model Delco starter and Motorola alternator.  The large Electro-mechanical solenoid on the Delco starter provides a more positive engagement of the drive gear.  In addition, the front of the armature is supported by a brass bushing.  These features give the Delco quite an advantage over earlier Prestolite starters, whose armatures tend to bend every now and then unless their drive units are kept clean and well oiled.

The only consideration in choosing a Delco starter is that a late model flywheel will need to be used as well.  The teeth on early model flywheels are slightly larger, and they will not mesh with Delco teeth.