I am about to buy a 1993 e350 van with a 7.3 and 400k miles on it. Runs fine now but I imagine it will need to be rebuilt within my ownership of it. How much did you pay for a rebuild and what was the final failure on the motor that made you decide to rebuild?

 

no failure yet. got a second engine that i want to get rebuilt and BUILT. quote was 1500-2000 for a basic rebuild.

 

I thought the 7.3L was a bored over 6.9L and the cylinder walls were thinner, thus rendering rebuilds undesirable. I could be completely wrong though.

 

the 7.3 walls are thinner, but you dont always have to bore over the cylinders when you do a rebuild. only if they are scared up. you can hone the cylinder walls. you can also sleeve the cylinder walls if you want. all depends on the condition of the block,.

 

Welcome to the IDI diesel forum!
The 6.9 IDI and 7.3 IDI are very similar and most external parts can be swapped between the two.
Find an '86 or '87 6.9 engine. Have the 6.9 rebuilt and install that into your truck.
Why? The 7.3 is a bored out 6.9, so the 7.3 cylinder walls are thinner. The 7.3's are prone to cavitation (when the cylinder walls develop pin holes and leak coolant into the cylinder). Don't bother with a rebuilt 7.3 because the cylinders are sleeved. Dave S. went through 3 rebuilt 7.3's where the sleeves were incorrectly installed. Finally, he built a 6.9 and is doing well. Oh, by the way, his 6.9 is far from stock and holds up excellent.
I don't have a ballpark number for a rebuild. However, members spend about 5,000 if the machine shop does the machining and you do the assembly.

 

Mileage doesn't really mean anything...... If it was properlly maintained, it can go another 300k miles as long as you keep it up.

 

You bring up a good point about the mileage! Maintenance is key!

 

id do a compression test,and see if it burns oil.if both are tolerable,id grab a new ip,set of injectors,have it professionally timed,and run her.
if it fails inside 100k mile,your not out anything.put the ip/injectors on the new(er)/rebuild and keep going.
cavitation check already mentioned.