Another old motor swap - BBC LS6 to LM7

[Ole Greenie]

Okay....So I have discussed this with a few of you all and decided to go ahead and do the swap to an LS motor. I’m replacing the BBC LS6 that has been in it for a quite a while. Sold it for a pretty penny which has more than subsidized this swap.

My choice was a 2002 LM7 5.3L. Yea, yea, I know. Why not go with more cubes? Right? Well, this motor came with everything and I didn’t have to pay for shipping or hunt one locally. It has about 90K on it so it is still pretty fresh. It has way more miles than the LS6 but probably has much less wear. I got it from a buddy who was looking for a big block to replace a tired 350 in his super nice 86' Silverado.

I have a couple goodies for it though like a new cam, valve springs and of course a tune W/O cats. I'm going to use the 2.5" exhaust so it should breathe after I install a wider TB. It should top out at just over 400HP/TQ which is plenty...though these 67-72 trucks are heavier than I thought they are. Anyone know the approximate weight? Should be saving over 200 lbs. of motor weight though.

So here are a few pictures so far. It is going into my 70 CST.









And one of the empty engine bay:


Lastly,

Although I have been exhaustively perusing the swap section, all builds are a bit different. I'm hooking this thing to a BTO Stage III 700R4 with a 3.73 LSD gear set. Are there any nuances I need to keep in mind for instrument cluster? What about mounting the PCM? Is there a favorable location?

Updating will be slow at times so please bear with me.

Take Care and God Bless all!