Dakota 5 spd to poly 318

Engine, transmission, rear-end, driveline, fuel system etc..
Post Reply
builder
Sweptline.ORG Member
Sweptline.ORG Member
Posts: 85
Joined: Sun Jun 14, 2015 7:51 pm
City: strathmore
State: Foreign

Dakota 5 spd to poly 318

Post by builder »

Dakota 5 spd to poly 318 is this do-able, i heard comments on drilled crankshaft for pilot bearing the truck has a np435 in it now but would like to bring the revs down on the hwy, I have swapped LA318 to poly 727's but this is different ?, thoughts anyone , experience doing this swap?

User avatar
Txas2step
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 3416
Joined: Mon May 31, 2010 7:26 am
City: houston
State: TX

Re: Dakota 5 spd to poly 318

Post by Txas2step »

You are probably running a 3:91 rear gear....change to a 3:23 if you are just trying to lower the rpm. Much easier. :2cents :Thumbsup
61 shorty 170/ 3spd 3:91(sold)
66 lwb 318 poly/727/4:10 (sold)
67 shorty 318poly/4spd 3:55
68 ute 318/3 spd/3:55(sold)
70 318/727/3:23
66 d200 225/4spd/4:10( military)(sold)
68 d100 383/727/3:55

builder
Sweptline.ORG Member
Sweptline.ORG Member
Posts: 85
Joined: Sun Jun 14, 2015 7:51 pm
City: strathmore
State: Foreign

Re: Dakota 5 spd to poly 318

Post by builder »

actually runnin 355, but going to change over to posi will keep that in mind

User avatar
slick
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 3095
Joined: Wed Dec 31, 1969 6:00 pm
City: Tucson/AZ
State: AZ
Location: Tucson, AZ
Contact:

Re: Dakota 5 spd to poly 318

Post by slick »

I would think its possible. The bellhousings are the same bolt pattern, so I don't see why not? Keep us updated.
1963 Crewcab
1965 Crewcab
1968 D-100 Longbed
1948 Dodge Panel Truck
1964 Dodge Polara
1957 Shasta

User avatar
PowerMan
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 1186
Joined: Wed Dec 31, 1969 6:00 pm
City: Auburn
State: CA
Location: Auburn, CA

Re: Dakota 5 spd to poly 318

Post by PowerMan »

I did an LA340 to a NV4500 swap which is similar. The Nv4500 uses a non integrated bellhousing unlike the NV3500 (Dakota 5 speed). Both of these transmissions were an option being the Magnum series 318 (5.2) and 360 (5.9) in the mid 90's to early 2000's. I held the NV4500 bellhousing up against the back 1962 Poly 318 I have and it had an issue with the two lower bolts at the bottom of the block not lining up. The 4 or 5 bolts along the top of the bellhousing line up just right along with the two dowel pins. While on the LA series engines, all of the bolt holes and dowel pins lined up.

I also used a Magnum 318 flywheel behind my 340 as they are a neutral balance while the Magnum 360 flywheels are not.

Also I was able to press the input shaft roller bearing in the back of my 340 crank without a problem. I know this may vary on other years and engine sizes so that may need to be addressed.
1962 W100 - NV4500- LU2 winch Looking for a 4BT!
1965 W200 CC 12 Valve P-Pump, HX35/S475, 5x12s, pushrods, 60# springs, 55 DVs, NV4500
1965 D100-> W100 Town Wagon 225 Slant - NP435

PwrWgnDrvr
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 7339
Joined: Wed Dec 31, 1969 6:00 pm
Location: Walnut Creek, CA

Re: Dakota 5 spd to poly 318

Post by PwrWgnDrvr »

The poly and LA both bolt to the exact same hydro bell in 67/68, so how can they be different, and if so, how was that addressed in those yrs?

User avatar
PowerMan
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 1186
Joined: Wed Dec 31, 1969 6:00 pm
City: Auburn
State: CA
Location: Auburn, CA

Re: Dakota 5 spd to poly 318

Post by PowerMan »

I went back and checked the bolt pattern on the Magnum Nv4500 bellhousing vs the bolt pattern on the 1962 Poly 318. All bolt holes and dowels line up except the lower driver side bolt hole.

Here is an example, my Dad's 64 W200 originally had a 318 Poly and later switched to a 1972 340 engine. After checking his truck it was apparent that he had drilled and tapped a hole in the Poly bellhousing to accomodate for the new hole location for the LA 340 engine. This new hole location is almost exactly in between the existing hole and the dowel pin in the bellhousing.

I also took a look at the Poly 318 bellhousing I had used behind my 1969 LA340 engine before the NV4500 swap, and it is apparent by the grease mark on the bellhousing that the LA340 had a different location for this lower driver bolt.

So in conclusion, if someone wanted to solve this problem while using an Nv4500 bellhousing or nv3500 transmission behind the Poly 318, they could easily drill the extra hole in the lower driver ear on the Poly 318 block.

On the other hand if someone was using the Poly 318 bellhousing behind an LA engine (assuming all LA engines have the same bolt pattern as the two LA340 engines I have used), a hole can be drilled and tapped to accomodate the new hole location required with for the LA engine.

My assumption is that the bellhousing hole location was changed in 66/67 when Dodge switched from the A to LA 318 series.
1962 W100 - NV4500- LU2 winch Looking for a 4BT!
1965 W200 CC 12 Valve P-Pump, HX35/S475, 5x12s, pushrods, 60# springs, 55 DVs, NV4500
1965 D100-> W100 Town Wagon 225 Slant - NP435

Kaegi
Sweptline.ORG Pioneer
Sweptline.ORG Pioneer
Posts: 1388
Joined: Tue Mar 18, 2008 12:49 am
City: Allyn WA

Re: Dakota 5 spd to poly 318

Post by Kaegi »

I have only seen the different poly bolt pattern on 61 and earlier blocks. any chance your polys are 61 or older?

Post Reply