Jump to content

MJ 350 swap


Recommended Posts

I'm looking to swap a carbureted sbc 350 in place of my 4.0. The only place I'm getting tripped up is wiring. Is anyone willing to share What they did to make that work. I don't really want to hack up the stock harness and get in over my head without a solid plan in place. Would it be easier to tuck the wires for the stock engine away and run a completely different harness with its own key switch and gauges so I can leave the chassis harness alone? If anyone was any input on this please do share.

Link to comment
Share on other sites

  • Replies 101
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

I have not touched any electronics behind the dash, so yes stock gauges are still there. I have not bought after market ones yet. As far as wiring goes I have not done anything. I don't have the motor yet but am looking to pick it up soon. Is there a custom harness that I could buy to make things a little easier?

Link to comment
Share on other sites

I used my factory body harness but completely removed the computers and engine wiring. That way I could hook up the factor gauges since the wiring for those is in the body harness that runs along the front of the mj. I did take that harness apart and thin out anything I didn’t need but you don’t have to do that. I have pics of everything I did in my build thread that was posted above. I also no longer have a carb but I did run one for about 2 years

Link to comment
Share on other sites

There are so many options here. For one, all you need to do is get the engine to run “stand alone”.  There is very little from the original harness that will need to be connected to the new engine. You’ll want to connect the oil presssure gauge, water temp, and oil pressure. Other than that you just need 12vto the coil while in the crank and run positions and a fuel pump for low pressure. The fuel system will be a bit of work. 

Link to comment
Share on other sites

50 minutes ago, Rusty Jeep said:

Does anybody make a customizable engine harness that will plug right in? 

 

 

 

Checkout the painless 10111 harness. It used the same fuse panel and bulkhead connector and is very universal. Made for an 87-90 YJ

Link to comment
Share on other sites

57 minutes ago, Rusty Jeep said:

What have you guys done to your fuel systems to accommodate a carburetor? 

What year MJ is this going in? See what the psi requirements are of your carb and select a pump appropriately. I’d recommend and in-tank pump of the right pressure rating. Other alternatives are in-line and mechanical block mounted pumps. The in-line fuel pumps can be quite noisy. The best in-line I’ve used is the Edelbrock quiet-flow. 

Link to comment
Share on other sites

Just a thought though too, efi on any sbc is super simple. There are such a huge amount of stand alone efi systems now that provide much more reliability and performance than any carb can offer. Fuel tech and Holley snipers are meant to replace a carb and give you step by step instructions that make the process very simple. Plus they can offer timing control. I like carbs on cars but after running 6 different carb setup off-road I switched to a Holley sniper setup and never looked back

Link to comment
Share on other sites

Just now, Rusty Jeep said:

Another question, has anybody swapped in a manual transmission that is not an ax15? It seems like most people go with the ax15 or automatics. I'm just wondering if there is a reason for that?

The AX15 is hard to beat.  It's strong and durable.  It's easy to swap.  There's a ton of aftermarket parts to support the swap.

Link to comment
Share on other sites

50 minutes ago, Rusty Jeep said:

Apart from modifing the shift lever and getting the nessesary adapter kits is there any reason a sm465 wouldn't work?

It would work well.  A little more custom work and not as many options in the aftermarket but it's a good option.  Also, you'd want to change your axle gears to compensate for not having overdrive.

Link to comment
Share on other sites

Behind a Chevy 350, you don't need an adapter kit.  Just OEM parts since it was a GM transmission behind the small and big block Chevy V8.

 

The only thing you need to do once the engine is in is to make sure the shifter fits, as well as fabbing up something for the transmission mount (if it doesn't happen to land in the right place already).

Link to comment
Share on other sites

3 hours ago, Pete M said:

does Novak or Advance Adapters have a kit for the sm465? 

Yes they do :L:. Np 205 I believe is a bolt up to the sm465 otherwise I suppose an adapter to a 231 would be needed. Wonder how a 205 tcase would fit. Fabbing up a new crossmember would be in order I’m sure. The sm465 is short though so the 205/465 combo probably wouldn’t be any longer than the stock drivetrain

Link to comment
Share on other sites

22 minutes ago, ghetdjc320 said:

Yes they do :L:. Np 205 I believe is a bolt up to the sm465 otherwise I suppose an adapter to a 231 would be needed. Wonder how a 205 tcase would fit. Fabbing up a new crossmember would be in order I’m sure. The sm465 is short though so the 205/465 combo probably wouldn’t be any longer than the stock drivetrain

It also came with the NP208 in some trucks depending on the year.

 

They were pretty much all passenger drop.  It was replaced by the NV4500 in 1992 when the K30 started the new body style as the K3500.  That was when they switched to IFS and driver drop.

Link to comment
Share on other sites

 

On 1/9/2021 at 3:22 PM, derf said:

It would work well.  A little more custom work and not as many options in the aftermarket but it's a good option.  Also, you'd want to change your axle gears to compensate for not having overdrive.

 

What gears would you recommend? 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share


×
×
  • Create New...