Head swap
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Junior User
Joined: Mar 2003
Posts: 97
Likes: 0
From: Forest Grove, OR
Head swap
I have tried the search but not getting anything. I am wondering about the 6.9 vs 7.3. The 7.3 is a reworked 6.9 correct? Can the heads from a 6.9 be used on a 7.3?
If the combustion chamber is a little smaller would it be too much compression? If this is possible could a turbo still be added and how much perssure could be used?
Are the strokes the same on the two engines since the 6.9 was bored to be 7.3?
Other idea if swapable is to put the 7.3 heads on a 6.9 to drop compression just a little and then turboed and the boost could be turned up much further.
Any thoughts on this?
Thakns,
Calvin
If the combustion chamber is a little smaller would it be too much compression? If this is possible could a turbo still be added and how much perssure could be used?
Are the strokes the same on the two engines since the 6.9 was bored to be 7.3?
Other idea if swapable is to put the 7.3 heads on a 6.9 to drop compression just a little and then turboed and the boost could be turned up much further.
Any thoughts on this?
Thakns,
Calvin
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Bored just a little, .011 if I remember right.
The stroke was a little longer by about the same numbers.
The 6.9 has 7/16" head bolts.
The 7.3 has 1/2" head bolts.
The 7.3 has 21 to 1 compression.
The 6.9 has 22.5 to 1 compression.
My book is on loan right now, so these numbers are off the top of my head.
Hope I got them all right.
The 7.3 has better valve stem seals than the 6.9 had.
A properly built 7.3 engine can take 15 PSI of boost without any trouble.
That is close to three times the stock setting.
All you have to do is the supporting mods to handle it.
ATS turbo and downpipe.
Pyrometer
Boost gauge
Exhaust at least 3" diameter with low restriction or no muffler.
Mod the intake ducting for better flow into the engine.
Get the injection timing set to about 8* BTDC.
And some pump tweeks.
An IDI can run with the big boys if you want it to.
No need swapping engine parts to something else that was not made to be there.
Just do a good maintence schedule often with the filters and oil changes, don't skimp on the products you use either.
The stroke was a little longer by about the same numbers.
The 6.9 has 7/16" head bolts.
The 7.3 has 1/2" head bolts.
The 7.3 has 21 to 1 compression.
The 6.9 has 22.5 to 1 compression.
My book is on loan right now, so these numbers are off the top of my head.
Hope I got them all right.
The 7.3 has better valve stem seals than the 6.9 had.
A properly built 7.3 engine can take 15 PSI of boost without any trouble.
That is close to three times the stock setting.
All you have to do is the supporting mods to handle it.
ATS turbo and downpipe.
Pyrometer
Boost gauge
Exhaust at least 3" diameter with low restriction or no muffler.
Mod the intake ducting for better flow into the engine.
Get the injection timing set to about 8* BTDC.
And some pump tweeks.
An IDI can run with the big boys if you want it to.
No need swapping engine parts to something else that was not made to be there.
Just do a good maintence schedule often with the filters and oil changes, don't skimp on the products you use either.
