5.2 Magnum and 46RH Swap

[Cudapile]

Hello
I have a 70 Cuda with no drivetrain.
I recently purchased a New 1993 5.2 Magnum long block for cheap.
So it doesn’t have a intake, valve covers, oil pan, flexplate, timing cover, exhaust manifolds, motor mounts, distributor or any accessories.
I would like to put a 46RH behind it with a 8-3/4 diff.
I need some suggestions on whether to go old LA accessories setup or new Magnum serpentine accessory setup.
I plan to use Magnum style intake with 4 barrel.
I also need advice on oil pans, exhaust, and motor mounts that work with E bodies.
Greatly appreciate your input on this setup, not interested in other swap options right now.

 

[Xcudame]

Do you have the magnum accessories like alternator, water pump and power steering? That helps the serpentine/old LA front accessories decision. LA intake won't bolt to the magnum heads, but there are aftermarket intakes for carburetors that will. There's also an oil pan to adapt magnum motors into cars. Check out Mancini Racing. If you have the 93 exhaust manifolds with the magnum engine, those are pretty decent exhaust otherwise headers. Regular 318 LA motor mounts will work with the magnum block. The ears should still be there. There's a couple of pieces of webbing on the 46rh you can hacksaw off and the thing practically bolts in with a modified trans crossmember.

 

[Cudapile]

Do you have the magnum accessories like alternator, water pump and power steering? That helps the serpentine/old LA front accessories decision. LA intake won't bolt to the magnum heads, but there are aftermarket intakes for carburetors that will. There's also an oil pan to adapt magnum motors into cars. Check out Mancini Racing. If you have the 93 exhaust manifolds with the magnum engine, those are pretty decent exhaust otherwise headers. Regular 318 LA motor mounts will work with the magnum block. The ears should still be there. There's a couple of pieces of webbing on the 46rh you can hacksaw off and the thing practically bolts in with a modified trans crossmember.

It’s a long block, so no timing cover forward and no valve covers or oil pan or flywheel.
I plan to use the Magnum Edelbrock intake # 7577.
This is why I’m trying to make a smart do it once plan before buying the parts needed.
Thanks

 

[Chryco Psycho]

Well my opinion is the serpentine system is better & if you have wrecking yards near you possibly you can get the parts there , the water pump is reverse rotation fyi , you can use magnum or older 5 bolt valve covers , the bolt pattern matches , the oil pan will be a special part , it is different than the LA engines as mentioned above & needs to fit the K frame so Milodon probably . I recall the 318 LA balancing is the same as the magnum 5.2 , I know the 5.9 is unique . LA headers bolt on or as mentioned the factory exhaust manifolds are some of the best if you can locate them . A LA distributor should work fine for you new or used from a wrecker .

 

[Xcudame]

The serpentine front end will definitely be easier to locate in a wrecking yard. The magnum 318 is internally balanced while the 360 magnum is externally balanced (uses a different flex plate and crank pulley/dampner). Rock Auto is also a choice for cheap parts for anything you can't find in a wrecking yard. Just make sure you use the LA distributor, because the magnum distributor is a completely different animal for the fuel injection setup.

 

[Cudapile]

Well my opinion is the serpentine system is better & if you have wrecking yards near you possibly you can get the parts there , the water pump is reverse rotation fyi , you can use magnum or older 5 bolt valve covers , the bolt pattern matches , the oil pan will be a special part , it is different than the LA engines as mentioned above & needs to fit the K frame so Milodon probably . I recall the 318 LA balancing is the same as the magnum 5.2 , I know the 5.9 is unique . LA headers bolt on or as mentioned the factory exhaust manifolds are some of the best if you can locate them . A LA distributor should work fine for you new or used from a wrecker .

Thanks for the info.
You mention factory exhaust manifolds, would those be for the LA or Magnum’s.

 

[Chryco Psycho]

The Magnum exhaust manifolds are some of the best flowing for any small block engine produced , if you can get the ones from a 5.9 they re slightly bigger / better .

 

[Xcudame]

If looking in a wrecking yard, the B vans (full sized) had magnum engines as well as the pickups. If nothing else, a pair of Summit headers for a LA engine will work in a pinch.

 

[Cudapile]

Well my opinion is the serpentine system is better & if you have wrecking yards near you possibly you can get the parts there , the water pump is reverse rotation fyi , you can use magnum or older 5 bolt valve covers , the bolt pattern matches , the oil pan will be a special part , it is different than the LA engines as mentioned above & needs to fit the K frame so Milodon probably . I recall the 318 LA balancing is the same as the magnum 5.2 , I know the 5.9 is unique . LA headers bolt on or as mentioned the factory exhaust manifolds are some of the best if you can locate them . A LA distributor should work fine for you new or used from a wrecker .

I have not found a Magnum oil pan that’s made to fit an Ebody, if anyone has a part number that would be great. Otherwise I will get a stock Magnum pan and modify it to fit.

 

[Xcudame]

See this oil pan at Mancini Racing
Mancini Racing Center Sump Oil Pan Kit - Raw

 

[Cudapile]

See this oil pan at Mancini Racing
Mancini Racing Center Sump Oil Pan Kit - Raw

Thanks for the link.
Interesting that in the description it say it will fit a 360 LA, what year and vehicle would that be.

 

[Xcudame]

I could be wrong, but I think the 360 magnum and 360 LA pan is interchangeable. The rear main on the 318 magnum was changed to 360 size so they only had to make one pan for the trucks and vans. Regardless the Mancini pan will fit a 318 magnum in an e-body.

 

[Chryco Psycho]

I hve installed a magnum in an E body , there is definately a pan for this .
Check with Mancini Racing , they will have it or the part # for sure .
I know the end seal is where the change was made .

 

[Xcudame]

Cudapile, when you get ready to install the 46rh into your 70 Cuda, these are where you cut the transmission ribs so you don't have to cut your tunnel.

 

[Cudapile]

Cudapile, when you get ready to install the 46rh into your 70 Cuda, these are where you cut the transmission ribs so you don't have to cut your tunnel.

View attachment 109221

View attachment 109222

Thank you for the pics, very helpful.

 

[Adam]

I believe the water pump on a Magnum turns the opposite direction from the LA, so would the fan. The outlets work for keeping the same radiator.

 

[Cudapile]

Hello
I have a 70 Cuda with no drivetrain.
I recently purchased a New 1993 5.2 Magnum long block for cheap.
So it doesn’t have a intake, valve covers, oil pan, flexplate, timing cover, exhaust manifolds, motor mounts, distributor or any accessories.
I would like to put a 46RH behind it with a 8-3/4 diff.
I need some suggestions on whether to go old LA accessories setup or new Magnum serpentine accessory setup.
I plan to use Magnum style intake with 4 barrel.
I also need advice on oil pans, exhaust, and motor mounts that work with E bodies.
Greatly appreciate your input on this setup, not interested in other swap options right now.

Thanks for all the info from everyone, it’s been very helpful.
I have a question about the flexplate to use with a 46RH trans. Looks like LA and Magnums have different diameters.
Any suggestions on distributors to use.
I’ve decided to go with LA style accessories in front and LA valve covers. I’m looking for a Edelbrock #7577 intake which fits the Magnum heads. I also will use the 5.9 Magnum exhaust manifolds to start with.
Can’t wait to hear this engine run.

 

[Xcudame]

Do you already have the 46rh transmission? With a torque converter or not? I'd go the 318 magnum flexplate and torque converter if possible to keep things simple. Try finding a good used 73 or 74 electronic distributor for a 340. If not, get the whole electronic conversion kit from Summit or Jegs with the orange ECU. Or a new Cardone distributor for a 73 340 from Rockauto.

 

[Cudapile]

I don’t have the 46RH yet so I can buy any needed parts.

 

[Chryco Psycho]

If you have a wrecker that has a magnum I would use the later serpentine system , 1 or 2 brackets mounts everything & the serpentine belt is superior , using LA parts you have so many parts to locate .