IIRC the LA and magnum are slight different on balance but there are ways to mix match them.

if you have LA engine the fly should be ok and fit in the bell. just figure out the disc size and spline count then use the hydro clutch pressure plate/TO bearing.

I used a 88 v6 flywheel on my 91 LA pre-mag roller 318 when I went to a 92-93 2x NV4500 in my 85 stepside. I used a 92-93 d350 11" clutch disc 19 spline. a course 10 spline is 4x4 (so a 11" 10 spline disc should fit)

FYI..what I found was mopar hydro bell for a NV4500 is just that. it only fits the NV4500 and has a 19 spline input shaft. larger input bearing retainer than the 435 4 speeds

so check input retainer size and see whats on there GM or MOPAR and check bell housing hole size.

the 88 v6 hydro bell fits the v6/LA/magnum engine and has duel bolt pattern for the a535/883/883OD 4 speed & the 435 4 speed (but does not fit the NV4500)



the NV4500 has trans mount 2 inches further back than a 70s-80s 2x chassis.

this may be helpful on yours as it is divorced xfer. I was able to turn the trans mount 180* do some trimming on it and the edge of cross member to clear the rear of trans and use the stock xmember & bolt location on the 85 2x chassis to bolt it all in. the NV4500 used a 727 slip yoke and I shortened the shaft to fit.

if I put mine back in I will fab up a xmember for clearance issues that the stock one has.

the 92-93 trucks had a different xmemeber as it was kinda L shaped and bolted on out side of frame rail on one side IIRC..

the 2x chassis had some changes from 88-93 gearing up for magnum engine change over.

cant bolt a BB engine in a 2x chassis after 87 due to chassis changes.

BUT maybe the trick I used to keep my stock xmember & location will work for you or I suggest fab one up.