I have a ford cvh 1600 what backfire through carborator only when it is hot and then lose its power

It's about 75mm long

Ford CVH is an old design but has proved itself long lasting and reliable. There is lots of information available about every aspect and the timing is among the simplest.
The weakest link has always been the water pump bearing that can fail very quickly without losing coolant. In the early days this was responsible for many bent valves.

To date I haven't experienced any problems with a dragging engine during starting that wasn't caused by the starter and/or battery. That the starter cable becomes hot indicates indicates it is consuming far more current than it should and mostly that would be the fault of the starter.
Does the engine spin over normally without the spark plugs?

try here might be of use to you

Ford Workshop Manuals

Hi
check timing marks on flywheel and crankshaft/pulley.
Remove no.1 plug to check it is just before tdc

the cvh has a weber carb. these usually need a service every now and then. the smoke suggests there is a over fuelling problem and the dying of the motor sue to some flooding, i fixed a cvh this past weekend with the same problems. make sure that all the air hoses are also connected to the various ports

Most computer controlled engines have a base setting . the computer has to be uncoupled to set this , your manual will show this ,as most models differ.

Fuel delivery problem, not enough fuel on acceleration could cause backfires. Many things cause backfires, mechanical and electronic. I need more info to give a better diagnosis. Did the problem happen all of a sudden or has the vehicle been running crappy for awhile.

No, they have an alternator

Check the auto choke to be sure its not getting stuck.

It sounds like the timing is off but moore likely it's caused by the point gap being to close due to wear on the rubbing block.
The gap of the points effects the timing.
You probably need to clean and adjust the points.
If that doesn't work try replacing the points and if the old one are pitted, replace the condenser also.
If that doen't work check the coil.