7.3 Heads on a 6.9

[icanfixall]

Whats wrong with running a set of 7.3 heads on a 6.9.... Besides the lower coolant passage being plugged with a freeze plug on the 7.3 heads they are the same as 6.9 heads... Even the gaskets are demensionally the same.... Just two coolant ports need to be changed in the 7.3 head gaskets... Or run a set of 6.9 head gaskets on a 7.3.... I'm not seeing a problem or reason why this can't be done. The exhaust manifolds will bolt up... the valve covers will bolt up.... The rockers will bolt up... the stock valves will be fine even if you run a turbo but... I would feel better with the turbo exhaust valves... They are made from inconel... I have heard thats all we can buy any longer... Nice way to force us to upgrade and the supplier doesn't need to stock two differant valves for these heads.... So why can't we install 7.3 heads on a 6.9... The head bolt diameter differance is 62 thousands so that only 31 thousands on each side of the bolt being smaller in the 7.3 heads... The washers will make that up easily.... Precups wont make any measureble differance either.... The valves are set into the heads the same amount.... Big question here guys... What do you think I missed...

 

[Diesel JD]

You are one of the most thorough member here when it comes to detail and doing things the right way....IDK, I was thinking the difference in bolt size might be a problem but I guess not. Hopefully others will have something to say about this.

 

[idiabuse]

I ran 6.9 heads on the 7.3, just needed to enlarge the head bolt holes, and make 8 spacers for the lower row of head bolts.
I dont see any problems doing the reverse either.

Javier

 

[429idi]

I tried 7.3 heads on my 6.9. I got the upper 2 rows of bolts threaded in, went to drop one in the bottom row and '****', it dropped all the way in. 6.9 head bolts are not long enough for the bottom row.

 

[idiabuse]

I tried 7.3 heads on my 6.9. I got the upper 2 rows of bolts threaded in, went to drop one in the bottom row and '****', it dropped all the way in. 6.9 head bolts are not long enough for the bottom row.

Yep you need 8 new head bolts, the lower row on 7.3 heads have a raised boss, I had to use spacers to put 6.9 heads on the 7.3.
Some new 7/16 bolts are in order to finish your head swap.

Javier

 

[shocktrooper]

I'm in the presses of outing 7.3 heads on my truck. I took out the freeze plugs for coolant flow. The dowel pins should line the head up and just gets her bolts for the bottom row

 

[BDCarrillo]

ARP makes shouldered washers specifically designed to use a 7/16 bolt in a 1/2 hole. Very common on SBF 302/351 head swaps

 

[shocktrooper]

Yea they have that also. Deciding if I should et those or not

 

[19887.3IDI]

I recently rebuilt a 6.9 and used 7.3 heads on it. I had the machine shop mill .550 of the bottom row and used the 6.9 ARP stud kit along with the 1/2 to 7/16 insert washers.

 

[shocktrooper]

Do you have the part number or where to get those washers?

 

[IDIoit]

ARP makes shouldered washers specifically designed to use a 7/16 bolt in a 1/2 hole. Very common on SBF 302/351 head swaps

with the dowel pins locating the head, the .062" difference in the holes are the only things i would be worried about.
easily remedy'd with Bryans post.
he may spell his name with a Y, but he is 100% correct

 

[BDCarrillo]

All prices are from summitracing.com

Trick Flow Specialties TFS-51400419 (20x pcs $49.97)
Edelbrock 9680 (20x pcs $56.97)
Airflow Research AFR 6324 (20x pcs $75.66)


ARP 200-8596 (1x pc, $4.43)
ARP 200-8597 (2x pcs, $8.44)
ARP 200-8598 (10x pcs, $40.54)

The ARP OD is the actual outside of the washer, the insert OD is .529"

 

[19887.3IDI]

200-8598 ARP insert washers

 

[Waystro]

I've wondered about this.
Back in a diesel power magazine some guy put a 6.7 cummins top end on a 5.9 cummins
anything can be done with time and money.

 

[shocktrooper]

You got that right ^^. How many of those washers am I gonna need? Or should I put them on all my head studs?