does anyone know how to identify a 300 HD. what casting numbers do i need to look for? what should the stroke be?

 

the blocks and all that are the same. th eonly difference is the cam and the pistons and the rocker arms. that's the only diff i know of

 

No easy external visuals. Pistons & crank are forged. Valves are sodium filled. Look at the calibration number and compare to known cal numbers.

 

300 HD?:-staun

Tell me more. What were they put in? Where can I get one? Will the crank fit a standard block? ANY info appreciated.

 

The 300 HD was used in many industrial applications ie generators, wood chippers, tractors. Some HD motors were put in trucks - typically comercial big boys even up to F600's. The HD was a special build that had low compression and a tough build. The forged crank can interchange with the cast crank. Other than the forged crank, pistons, Na filled valves, and larger rad., the HD is identical to the LD. HD applications were also void of emissions equipment for the most part. Finding one is tough. You can't buy one off the shelf. Case in point: I though for sure I found one in a '75 one ton flat bed at a local junkyard. It had no emissions equipment, the HD application valve cover...it ended up being a rebuilt 240. Thank godness I already have a cast crank already to go. Unless you're planning on turning more than 6K, you should be A-ok with the cast crank. For the valves, a nice set of stainless undercut will do well too. Remeber the 300HD was not a performance motor by far, it was a longevity motor.

 

Also, not all HD's had forged cranks. I'd imagine they said "Why go forged when we aren't having a problem with the cast?"


-=Whittey=-