New motor, 6.9 or 7.3??

[fastass350]

I'm finally going to bite the bullet, instead of taking the time to rebuild one of my engines, I'm going to buy a rebuilt from a local rebuilder that I've dealt with many times before and trust. I can either go with a 6.9 or a 7.3, which would you choose and why? I tend to be kinda ******* my trucks, pulling and hauling, 4 wheeling and such. I always warm them up, keep fluids good and changed, and don't let them get hot.
I tend to want to stick with the 6.9 because I feel in the long run they are stronger and will last longer, less weak points. I have cores available for either, so should I go with the 7.3 since I'll have a warranty? I'll more than likely never ever run a turbo cause I hate them.
They want 2800 for a long block, which seems good to me. They always sleeve number 8 (the one that usually gets the pin hole) and everything else is new or reconditioned. That's only a little more than if I have someone do all my machining and I put it together myself.

What do you think?

 

[Rot Box]

When the time comes I'm going with the 6.9 and head studs. The heads have better cooling passages (so I hear ) and the cylinder walls are thicker My 7.3 likes to get hot when I work it hard and the 6.9's don't seem to have that problem so much.

Why do you hate turbo's?! I don't know it I could live with a n/a IDI again at my elevation.

 

[jonathan]

dont just sleeve number 8 its best to sleeve all 8 on 7.3s. the 6.9 is good to if its a pre 85 block just dont use the block heater

 

[fastass350]

I hear ya about elevation, mines always turned into a **** over 4000, I just hate everything about working on the turbo'd ones. I wouldn't mind having one, but have never felt I needed one enough to justify the anguish of working on em If I need a powerhouse to pull something I'll use the other truck.

 

[lotzagoodstuff]

If you aren't going turbo, I think the 6.9 is the way to go. I feel like the only shortcoming of the 6.9 is the smaller head bolts, but if you aren't going to boost I think it's fine.

I have a 7.3 that I bought from the original owner, and it's always had SCAs maintained, but even with a warranty you've got to have that block worm in the back of your mind. Sleeving can be done correctly, but it is one more thing to worry about.

What would really be cool would be a 6.9 block machined for the larger head bolts, so you could run the more reliable block with the bigger studs. Can it be done?

Just my .02 worth, I am sure either can be built to be very stout/dependable.

 

[fastass350]

Speaking of sleeving, they told me they do the better of the two sleeve styles, they use a flanged sleeve, so when things heat up after the sleeve is installed and the engine run, it won't shrink leaving a recessed sleeve below the deck.
I always check the coolant with the test strips so that doesn't bother me too much. I'll have to ask them about the larger head bolts, but there again I won't need them for what I'm doing, but couldn't a guy just stud the 6.9 and have near the same effect?

 

[MUDKICKR]

id go 7.3, no replacement for displacement.

 

[icanfixall]

Go with the 6.9 and bore 20 over and stud it... Studs are insurance. They are added insurance though. A 6.9 usually is never sleeved. Using the flanged top sleeves is the only way to go but.... They require more work to install properly. They are the best. A 7.3 non turbo is not much more powerful then a 6.9 so go with the 6.9. It has thicker cylinders and never cavitates. Sleeving all 8 on the 7.3 is really the only true way to repair that block. A few guys have bored then 20 over and got away with it but thats not the norm either...Every part inside these motors is the same from the 6.9 to the 7.3 except the pistons or turbo rods. They are the same part number too. Thats the bearings, crank, rods (nonturbo in both motors),cam, oil pump, oil cooler, timing gears and such... The head gaskets are the only gaskets that are differant between each block. Hope this helps build your motor.