Head Case

[Knuckledragger]

Is there any problem installing 7.3 heads on a 6.9 block? I know to use good washers to compensate for the larger head bolt holes, unknown if there are passages or other holes that changed.

Getting ready to rebuild a 6.9 and want to upgrade to the improved valve train and better castings of the late 7.3 heads. I had all sorts of cracks (between valves) on the 6.9 heads the first time I tried to do a valve job.

 

[Hydro-idi]

Not too sure about this one, but it might be worth a try. You might have to put a sleeve in the holes to take the slop out & better fit the 6.9 bolts. Other than that, they should bolt right up. You can take the rear coolant plugs out to aid in engine cooling as well. The factory plugged the ports in the 7.3 Idi cylinder heads in hopes to meet emission standards at the time.
Been having issues with cracked heads myself and was about to experiment with 7.3 heads. My machine shop pinned (loc&stitch) all the cracks & did a damn good job doing it. He's been doing it for years on cast iron heads with no probs. Was an additional $250 but wanted it done even though cracks weren't severe. You could go that route if all else fails.

 

[79jasper]

It'll work. @icanfixall knows more.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[icanfixall]

Sometimes I know too much for what is good for me. Mike all you do with the 7.3 heads is open up the freeze plug to look like the 6.9 head gasket opening. No need to completely remove the plug when the head gasket is only going to allow what coolant can pass thru that opening. As for special sleeves or washers.. Simply not needed. Measure the difference in the heads to see how much the larger hole for the 1/2 inch bolts are. Its frankly not enough to worry bout. Also the bolt pattern is the same between the heads as is the alignment dowels.

 

[Knuckledragger]

Thanks, Gary. I couldn't remember if the coolant block was in the head or the gaskets. I'll use studs since it is a turbo engine, and washer thickness will not be an issue.

 

[Hydro-idi]

Thanks for reply Gary. Is there any literature stating that the 7.3 Idi cylinder head is more resistant to cracks?? I have seen similar cracking with both 6.9/7.3 heads.....
I can say, it's much easier to find parts for these 7.3's & this info is good to know.

 

[TahoeTom]

Measure the height of the casting at the lower head bolts. I believe the 7.3 heads are thicker than 6.9 heads in that area, so stock 6.9 studs will be too short. There was a thread awhile ago regarding this. I'll see if I can find it and report back.
Edit: OK, I found the thread. The part # for ARP stepped washers is there also if you decide they are necessary.
http://www.oilburners.net/forums/showthread.php?46461-7-3-Heads-on-a-6-9&highlight=arp+200-8598