Swapping a 7.3 IDI to a 6BT 12 Valve Cummins

Laine D

Full Access Member
Joined
Jan 23, 2019
Posts
1,032
Reaction score
1,362
Location
Northern California
Carrick customs has a really nice a/c bracket but it is for the serpentine style compressor. As far as an adaptor plate I’m assuming it’s the same as a zf5 one because the bolt holes are the same and you don’t need to change anything when you go from c6 to zf5 on and idi anyways. I’m not sure what you’d do for a converter though. I’m sure there’s something
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
9,010
Reaction score
7,213
Location
edmond, ks
Actually, the fact that the transmissions will interchange between the IDI and 7.3 PSD doesn't mean anything. I was talking about the bolt pattern on the back of the engine block being changed on the 7.3 PSD, not the transmission bolt pattern. It's an International (Navistar or whoever made it) engine and a Ford transmission. Since the transmission bolt patterns are the same, that means that Ford didn't change the bolt pattern, International did.
 

snicklas

6.0 and Loving It!!
Staff member
Joined
Aug 7, 2006
Posts
5,961
Reaction score
2,043
Location
Greenfield, Indiana
Go take a look at Project Big Ed.... or something like that. Darrin has a 6BT Cummins in front of a C6 in a Crew Cab Bricknose truck.

Darrin has done a lot of custom work on that truck and also on Droopy.. it is a 4BT in front of a ZF5 in a Regular Cab Bricknose truck.

I have seen both trucks (been friends with Darrin for a long time) and the are both top notch conversions. I've driven Droopy, and it is surprising how well that "little 4 cylinder" moves that truck along.
 

CDX825

filtration nut
Joined
Aug 4, 2008
Posts
1,347
Reaction score
85
Location
Litchfield,Ohio
The bell housing pattern on these trucks is the same regardless of the transmission. Its close to a 460 bell housing but not the exact same. They have different dowel pin locations. The 7.3 powerstroke is also the same bell housing as the IDI.
 

Lezgo Brandon

Registered User
Joined
Nov 24, 2021
Posts
9
Reaction score
1
Location
FL
Tharrs also DCS (Diesel Conversion Specialists) I myself busted windshield-perfect purring 97 3500 DRW 2WD NV4500 12valve bucket o rust and a blown Head gasketed 7tree idi 93 4" lift 4x4 , believe me, my mind says "do it!" Outback in the dirt my wallet (& low back ) says part ways with the obs. :drunk:
 

Lezgo Brandon

Registered User
Joined
Nov 24, 2021
Posts
9
Reaction score
1
Location
FL
(oh, it's got a perfectly fine zf5 as well...$hes on FB Market pl.)
 

Eli

Full Access Member
Joined
Sep 9, 2013
Posts
181
Reaction score
42
Location
Texas
Yeah, that's cool man. I'm not dead set on the 5.9. But I would like to do a straight axle swap on the front, and haul logs fully loaded on a 14k-16k gooseneck.

I did look up the banks sidewinder kits, that plus a upgraded pump and injectors would maybe suffice.

I do not want to relocate the Trans. I already shortened my 2 peice shift to fit the GV unit. Any shorter and I'll need to go with a 1 peice shift. So if the 5.9 requires relocation of the drive train, I'll prolly go the turbo route.....

But that 5.9 SOUND!!!! It's screams MURICA
The 6BT (Cummins 5.9) is no more powerful than a healthy IDI.
Without the GV OD, that C6 would limit you to less than 60 MPH at the Cumapart's maximum 2500 RPM - the IDI revs 3300-3400 stock and 3800 with an aftermarket IP - and even with the GV OD that 6BT won't be happy at highway speeds.
Cost to convert will run well in excess of $10,000 unless you have a fully equipped machine and fabrication shop.
Sounds like your IDI is sick, you might get a competent mechanic to check the timing before making grandiose plans.

Eli
 

u2slow

bilge rat
Joined
May 8, 2007
Posts
1,284
Reaction score
413
Location
PNW
and even with the GV OD that 6BT won't be happy at highway speeds.
I don't follow. My cummins dodges are happy at highway speeds and 3.54... common ratio for Fords too.
 

Eli

Full Access Member
Joined
Sep 9, 2013
Posts
181
Reaction score
42
Location
Texas
I don't follow. My cummins dodges are happy at highway speeds and 3.54... common ratio for Fords too.
Your Cummins Dodges have lock-up torque converters - and, probably, overdrive - the C6 does not.
Assuming LT235/85R16 tires and 0% slippage, maximum speed is around 66 MPH. But, because of the torque converter slippage, realistically that Cummins is against the governor at 60-65 MPH; maybe less under load.

Eli
 

u2slow

bilge rat
Joined
May 8, 2007
Posts
1,284
Reaction score
413
Location
PNW
@Eli OP says he's got the GVOD on the C6... that's why it didn't make sense. Not sure what its OD ratio is though.

I've pushed my '90 cummins to 80mph with 3.54, 33's, and OD (5spd so no TC slip). No mods other than a smidge of timing advance. There may be more left on the table, but the road and truck condition were not optimal. LOL
 

Eli

Full Access Member
Joined
Sep 9, 2013
Posts
181
Reaction score
42
Location
Texas
@Eli OP says he's got the GVOD on the C6... that's why it didn't make sense. Not sure what its OD ratio is though.

I've pushed my '90 cummins to 80mph with 3.54, 33's, and OD (5spd so no TC slip). No mods other than a smidge of timing advance. There may be more left on the table, but the road and truck condition were not optimal. LOL
I forgot about the GV OD, looks like it might push it to around 86 MPH with 0% slippage - but, again, that's against the governor.

Eli
 

u2slow

bilge rat
Joined
May 8, 2007
Posts
1,284
Reaction score
413
Location
PNW
FWIW, a 3200 governor spring for a 6BT is a <$20 upgrade... for those that need to go faster.

There's a 3600rpm also, but then exhaust valve springs should get upgraded.
 

KYBricksandBulls

Registered User
Joined
Feb 16, 2021
Posts
59
Reaction score
60
Location
Somewheresville KY
The 6BT (Cummins 5.9) is no more powerful than a healthy IDI.
Without the GV OD, that C6 would limit you to less than 60 MPH at the Cumapart's maximum 2500 RPM - the IDI revs 3300-3400 stock and 3800 with an aftermarket IP - and even with the GV OD that 6BT won't be happy at highway speeds.
Cost to convert will run well in excess of $10,000 unless you have a fully equipped machine and fabrication shop.
Sounds like your IDI is sick, you might get a competent mechanic to check the timing before making grandiose plans.

Eli
The IDI is healthy. Just turned 100k miles and starts in the cold in less than 5 seconds. I am a competent mechanic, boss.

Been wrenching for 21 years now. I just really like the Bricknose style, and the cummins simplicity, sound, and power potential over the 7.3.

I had a 40x50 shop, lift, tools to back it up. Owned 35 vehicles in my life thus far.

No way it'll cost $10,000.
 
Top