Magnum swap questions installing a 4 speed behind it

Dropped my magnum motor for my 70 satillite off to get the cam snout adaptor from Hughes installed on it so I can make the motor look correct appearance wise. I’ve also decided to go 4 speed behind it As well. I can’t find any one that has installed a 4 speed behind one. I check the pilot hole and it’s
To shallow. So I asked the machine shop to drill it out more and they said they should be able to no problem. There’s a 340 sitting right next to it in the shop to go by as far as depth.

I’m going to grab a timing chain cover off of a 318 I have kicking around and I’ll also use all the alt, power steering and pulleys off it as well. My only question is what will I use for a harmonic balancer now. Should I order a 360 la style harmonic balancer for it? Any recommendations?

5.2 or 5.9? I don't have an answer but this might get some feedback going.

Sorry 5.9

I think you will want to stick with the 5.9 Magnum flywheel and harmonic balancer so as not to affect your engine balance.

no I don't think you can use that.
someone will chime in that is sure, but it is neutrally balanced as I recall and the la 360 one is not.

I copied this when Dog posted awhile back: 5.9 mag (360) external balance is different from a LA 360 external balance amount. 5.9 mag-use OE 5.9 flexplate/neutral converter. 5.9 Mag imbalance is in the flexplate. 360 LA imbalance is in the converter. 5.2 (318) mags are internally balanced as are all LA 318. 5.2/5.9/LA 360 use the same oil pan (sump locations vary of course-need different pickups) but use mag gasket with 5.2 & 5.9 pan & LA gasket with a 360 LA pan (on a mag block I am assuming he meant). this ain't helping you with a stick app & someone had posted something about some 5.9 mags haveing a different balance than other years of 5.9 LA (Dog will (likely) clarify when he comes to).

I might give these guys a call tomorrow about this

Drilling the 5.9 magnum out for the longer input shaft from a b body 4 speed ok?

I’ll look around and see if I can find a magnum flywheel.

Should be fine drilling it, BUT have shop check for any oil passages that may be there, in other words dont go to deep. You could also just shorten the trans input shaft and install the magnum pilot bearing in hub of crank. You must use a magnum balancer.

If you need 130 tooth wheel for 10.5 cluth it was mopar p5249842, carb only not set up for crank sensor, I think mcleod makes one also. P4876056 for a pilot bearing, magnum style.

It was cheaper for me to have the crank balanced and use my old flywheel, I assume they are pulling the crank to drill it, if not I would run away. I disagree on the no big deal to drill it, was a big deal for me to get a billet hemi crank drilled and machined right but they may know something I dont. I would ask some questions. Here are the specs from a 360 magnum.
Piston 470
Pin 134
Rod small 225
Rod big 519
Rings 40
Rod bearing 47.6
Recip weight 869
Rotate weight 566.6
Weight per cylinder 1435.6
Bobweight 2002.2

These figures worked for my stock 360 mag 20 years ago, use at your own risk.

Ok cool so cutting the input shaft down and using the magnum style bearing sounds good to me. I’ll go with a new magnum style balancer posted in the pic above. And now I just need the right magnum flywheel to bolt up behind it. I’ll look on eBay and see if I can find one.

I dont think a truck flywheel will work with an aluminum bellhousing, dont remember exactly why, maybe 143 tooth vs 130, what do you have now 130?

Actually I’m not sure, I thought 143.

Might work for you then.

My aluminum bell was a 130, think 143 hits things in there, and starter wont fit.

Found two on eBay
One is 130 and the other was 143 out of a truck. The 130 was over $500. Really pricey!

They must of made two magnum style flywheels 130 and 143. I guess I should be looking for the 130?
Thanks for all the help

The 130 was never an assembly line piece, mopar did it for the crate motors. Crank sensor will not work so I hope you are using a carb. And yes its $$$.

Yah carb

10.5 “ is the diameter I want correct?

If you have a 1970 and up car aluminium bellhousing yes. Other years may be the same I dont know.

When I converted to a 360 my machine shop drilled my neutral flywheel to 360 specs. So I could use it.

Yes, someone posted 360 magnum drilling specs on here at one point. I think it was John Kunkle, do a search. The figure I have is 12.82 inch oz of imbalance. If you do a google search specs and location of the hole is out there.