250 vs 200

[FrankBoss]

Which to choose...

ok it boiles down to the performance needs out of the motor.
I want a mostly stock motor. Mild cam no header...
But I want to be able to move a load...towing.

is the 200 all around the best or is the longer stroke supreme?

Frank

 

[addo]

If you can afford to build a motor for a specified application, then the 250. If it's budget-zero territory, then a 200 will waste less fuel.

 

[Lazy JW]

For towing (torque) there is no substitute for stroke. Use the 250.
Joe

 

[FrankBoss]

I have had some old timer ford mech's tell me the 250 wasnt as strong as the
200 . Over heating and bad stroke ratio.... Any more feed back?

Frank

 

[Lazy JW]

I have had some old timer ford mech's tell me the 250 wasnt as strong as the
200 . Over heating and bad stroke ratio.... Any more feed back?

Frank

Methinks they have been smoking more than their worn-out engines
Joe

 

[CZLN6]

Howdy Frank:

The stroke-to-rod ratio is identical on the 200 and 250 at 1.5:1.

The only flaw in the 250 that accounts for some of it's problems is a huge deck height, or the distance the piston is down from the top of the block. Mine was down .150"!! FoMoCo did this to reduce CR to 8.2:1. This spec will very from .100" to .150"- so much for quality control.

This much deck height causes lousy combustion turbulence and leads to pre-ignition and detonation. The problem can be improved on during a rebuild, but it is not easy. The simplest solution is to use pistons from a ford 255 V8, which will stand .085" taller, and then deck the top of the block to achieve zero deck height. You will need to enlarge the combustion chambers in the head to achieve your Compression Ratio goal. The thicker aftermarket composite head gaskets will give you aproximately .050" total deck clearance (deck height + head gasket thickness).

A 250 built like this will be every bit as fuel efficient as a 200, when tuned properly.

Adios, David