v-6 in early A-body
I completely disagree with 98% of your post. First, they didnt drop the V6 when they had room for a V8. The Dakota had both and still does, as well as using them in Rams and unmentioned Durangos. The Magnum 3.9's were excellent engines for small trucks and 2wd 1/2 ton trucks if you didnt haul heavy loads. They got great MPG and were super reliable. I have worked on hundreds of them over the last 20 years of running a Magnum Performance shop and have never had a complaint about vibration. Third, your comment about loosing crank trigger is WRONG. Its easy to run factory injection with a 904 or 727, you simply have to notch bellhousing for crank trigger and use magnum flywheel. I have done this in CJ Wranglers and currently have a 65 Dart running 904 as well as a 67 Dart GT Vert we just installed 5.9 in , all with injection. There is some cross member modification to fit a 44/46 RE in a 67+ and some additional floor mods on 64-66 but the 67+ are not hard at all. That was the only part of your post I agree with and was wondering have you ever done the swap? Have you ever owned a magnum engine? The Allpar article was written from a point of author not liking his 3.9 van and in the end of article it even mentions issues form bad O2 sensor and CPM sensor causing rough running and drivability issues....in other words he just vented his dislike of 3.9 by bashing earliest design which nobody uses. Here is another interpretation of 3.9
Magnum 3.9L[edit]
As the 5.2L V8 was introduced in 1992, the often-forgotten V6 version of the Magnum engine became available in the Ram pickup and the more compact Dodge Dakota. Based on the LA-series 239ci V6, the 3.9L featured the same changes and upgrades as the other Magnum engines. The 3.9L can be better understood by imagining a 5.2L V8 with two cylinders removed.
Power increased substantially to 180 hp @ 4,400 rpm (134 kW)and from 195 lb·ft (264 N·m) to 220 lb·ft (298 N·m) @ 3,200 rpm, as compared with the previous TBI engine. For 1994, horsepower was reduced to 175, mostly due to the installation of smaller-volume exhaust manifolds; torque ratings remained the same.[5] For 1997, the 3.9L engine's torque output was increased to 225 lb·ft (305 N·m), with a compression ratio of 9.1:1.[5] Firing order was 1-6-5-4-3-2.[5] This engine was last produced for the 2003 Dodge Dakotapickup. Starting in the 2004 model year it was entirely withdrawn from production and replaced with the 3.7 L PowerTech V6 engine.[14]
A much more objective description in my opinion. I also disagree on your mini van engine. If you have ever driven a 3.8 JK Wrangler, they suck! No torque, wrong powerband for Jeep and get horrible MPG. They would have been much better off with the 3.9 or 3.7 anthough I am not a 3.7 fan, it would have at least made it easy for latermodel 4.7 swaps. You only option now is Hemi.
BTW hacking 2 cylinders off a V8 was also done on GM's VERY popular 4.3L V6 which shares 5.7 GM parts as the 3.9 to 5.2 does. Its been succesfully done for years quite successfully, the Mopar version just isnt as famous.
OP it will be a great swap, just stick to 1996+. CJ Jeeps are not much heavier than an A body so it will be fun economical and still spin the tires!
904 trans notched for Crank Sensor
5.9 showing Crank Sensor bolted on.
64 5.2 44RE pre fit and 3.9 is much shorter than this!
V8 harness ready for install, V6 is almost identical.
I completely disagree with 98% of your post. First, they didnt drop the V6 when they had room for a V8. The Dakota had both and still does, as well as using them in Rams and unmentioned Durangos. The Magnum 3.9's were excellent engines for small trucks and 2wd 1/2 ton trucks if you didnt haul heavy loads. They got great MPG and were super reliable. I have worked on hundreds of them over the last 20 years of running a Magnum Performance shop and have never had a complaint about vibration. Third, your comment about loosing crank trigger is WRONG. Its easy to run factory injection with a 904 or 727, you simply have to notch bellhousing for crank trigger and use magnum flywheel. I have done this in CJ Wranglers and currently have a 65 Dart running 904 as well as a 67 Dart GT Vert we just installed 5.9 in , all with injection. There is some cross member modification to fit a 44/46 RE in a 67+ and some additional floor mods on 64-66 but the 67+ are not hard at all. That was the only part of your post I agree with and was wondering have you ever done the swap? Have you ever owned a magnum engine? The Allpar article was written from a point of author not liking his 3.9 van and in the end of article it even mentions issues form bad O2 sensor and CPM sensor causing rough running and drivability issues....in other words he just vented his dislike of 3.9 by bashing earliest design which nobody uses. Here is another interpretation of 3.9
Magnum 3.9L[edit]
As the 5.2L V8 was introduced in 1992, the often-forgotten V6 version of the Magnum engine became available in the Ram pickup and the more compact Dodge Dakota. Based on the LA-series 239ci V6, the 3.9L featured the same changes and upgrades as the other Magnum engines. The 3.9L can be better understood by imagining a 5.2L V8 with two cylinders removed.
Power increased substantially to 180 hp @ 4,400 rpm (134 kW)and from 195 lb·ft (264 N·m) to 220 lb·ft (298 N·m) @ 3,200 rpm, as compared with the previous TBI engine. For 1994, horsepower was reduced to 175, mostly due to the installation of smaller-volume exhaust manifolds; torque ratings remained the same.[5] For 1997, the 3.9L engine's torque output was increased to 225 lb·ft (305 N·m), with a compression ratio of 9.1:1.[5] Firing order was 1-6-5-4-3-2.[5] This engine was last produced for the 2003 Dodge Dakotapickup. Starting in the 2004 model year it was entirely withdrawn from production and replaced with the 3.7 L PowerTech V6 engine.[14]
A much more objective description in my opinion. I also disagree on your mini van engine. If you have ever driven a 3.8 JK Wrangler, they suck! No torque, wrong powerband for Jeep and get horrible MPG. They would have been much better off with the 3.9 or 3.7 anthough I am not a 3.7 fan, it would have at least made it easy for latermodel 4.7 swaps. You only option now is Hemi.
BTW hacking 2 cylinders off a V8 was also done on GM's VERY popular 4.3L V6 which shares 5.7 GM parts as the 3.9 to 5.2 does. Its been succesfully done for years quite successfully, the Mopar version just isnt as famous.
OP it will be a great swap, just stick to 1996+. CJ Jeeps are not much heavier than an A body so it will be fun economical and still spin the tires!
904 trans notched for Crank Sensor
5.9 showing Crank Sensor bolted on.
64 5.2 44RE pre fit and 3.9 is much shorter than this!
V8 harness ready for install, V6 is almost identical.