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318 swap to 225 in a 89 w150 truck?
http://slantsix.org/forum/viewtopic.php?f=19&t=62699
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Author:  Haywire [ Fri Aug 10, 2018 3:20 am ]
Post subject:  318 swap to 225 in a 89 w150 truck?

Need some help please I’m not a very knowledgeable on Dodge. I have a 89 W150 4 wheel drive truck with a 318 police interceptor ( so I was tolled ) with a full cam. So I lucky to get 10 miles to the gallon. I would like to replace it with the 225, would the bell housing with the double bolt pattern fit that transmission?
And could I get that hydraulic clutch to work? Thanks for any help you could give

Author:  coconuteater64 [ Fri Aug 10, 2018 5:29 am ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

Haywire wrote:
Need some help please I’m not a very knowledgeable on Dodge. I have a 89 W150 4 wheel drive truck with a 318 police interceptor ( so I was tolled ) with a full cam. So I lucky to get 10 miles to the gallon. I would like to replace it with the 225, would the bell housing with the double bolt pattern fit that transmission?
And could I get that hydraulic clutch to work? Thanks for any help you could give

1. What is a "full cam"? That's of no help. It's like a doctor saying, "You have some blood pressure." A 318 Police Interceptor was essentially a 318 with 360 heads.
2. Ten miles per gallon seems about right for that combination.
3. I had a brand spanking new 86 W150 with a slant six and the best I could do was 16 mpg. That's a big old truck with a lot of parasitic drag in the drive line.
4. It's a fairly straight forward swap, though I have only ever done it the other direction. From front to back:
The radiator's top hose is on the wrong side for a slant six. You can make it work (that's what I'm using) if you have a friendly parts counter guy who will let you eyeball an upper hose. The fan shroud won't work, as the slant is longer. You'll need frame mounts for the engine, as the V8 pieces won't work. Wiring up the distributor is easy. You'll need some exhaust work to mate up with the V8 exhaust. Since no slants I know of had a hydraulic clutch, you're on your own there.

After all this, you'll end up with an under-powered truck that doesn't get much better mileage than the 318. Not trying to talk you out of it, but there's nothing to really be gained by it unless you have a fresh slant handy and a worn out 318. You're time and money ahead if you just freshen up the 318, put in a lower RPM cam and a small 4 barrel carb, true dual exhaust, and just enjoy it.

Author:  Reed [ Fri Aug 10, 2018 7:04 am ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

The 89 would have had thtottle body fuel injection and a fully computer controlled ignition system. Those systems will have to change if you want to install a slant six.

Honestly, I recommend keeping the 318 and working with it to improve fuel economy. 10-13 is about as good as you will get in that old truck unless you spend a lot of money. I don’t think a swap to a slant six is the best choice for that application.

Author:  Rick Covalt [ Sat Aug 11, 2018 5:16 pm ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

Quote:
Since no slants I know of had a hydraulic clutch


Some early (60's) trucks had hydraulic clutches and my 85 D100 had a hydraulic clutch with the OD transmission.

Author:  coconuteater64 [ Sat Aug 11, 2018 9:15 pm ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

Rick Covalt wrote:
Quote:
Since no slants I know of had a hydraulic clutch


Some early (60's) trucks had hydraulic clutches and my 85 D100 had a hydraulic clutch with the OD transmission.

Learn something new every day.

Author:  Joshie225 [ Sun Aug 12, 2018 9:12 am ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

I would also work on the 318 before swapping to a 225. If you really wanted good fuel economy you'd be driving something else. For the sake of argument we'll say your requirements are a full size 4x4.

Does the truck still have throttle-body fuel injection? If not please describe the fuel system.

Does the truck still have the roller cam engine block?

"1985-’89 CAR AND 1985-’90 TRUCK
Chrysler changed the block in ’85 to accommodate roller lifters by adding three bosses in the lifter valley for the lifter holddowns. Roller lifters were used from 1985-’89 in all domestic cars, except police cars (’89 was the last year for the RWD car) and from ’88 on up in domestic trucks. Canadian cars and trucks both got rollers in ’88."

What is the cylinder head casting number?

Once we have this information, and maybe a little more, we can help improve the fuel economy without undertaking an expensive engine swap.

Author:  Tim Keith [ Sun Aug 12, 2018 10:31 pm ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

I'd be mostly happy with the 10 MPG - used as a weekend vehicle. If you need a truck for light duty daily use there are better options. I paid $700 for a V6 Dakota that runs well and gets 21 MPG - it needs paint - the A/C doesn't work, but for what it is I can't complain. A W150 is pretty cool, you could probably get a little better than 10 MPG depending on gearing. I've rented some late model trucks Dodge, Ford, GMC and they got 14 MPG - so you probably can't hope for too much from the W150. That would be a good truck for off road use. I wouldn't swap to a six.

Author:  enrique lopez [ Wed Aug 14, 2019 2:38 pm ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

Hi Hywire,,

I have a 1982 D150 with a slant 6.
After a lot of work, I am excited to get 17 miles to the gallon.
Prior to buying a new carb, upgrading to a HEI, and a complete tune-up, the most I could get was 13 miles to the gallon..

A W150 is a lot heavier than my D150, I don't think you will see too much of a difference as far as fuel economy,,
What will happen, You will for sure lose a lot of power..

Author:  afastcuda1970 [ Thu Aug 15, 2019 3:20 pm ]
Post subject:  Re: 318 swap to 225 in a 89 w150 truck?

Best I got was 12.5 mpg out of my 84 w150 w/slant6. I just swapped in a e48 police 318 but have no mpg report yet. If you buy a new carb for the 318, I recomend the 625 cfm street demon and then tune it.

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