BoostForBreakfast

I am in the middle of a teardown of an LM7 I'm freshening up (spun rod bearing) to put into my Audi (with a couple snails hanging off of it). The audi has a small engine compartment and I'm trying to get all the space I can in the front. I'm wanting to kind of build a Longitudinal, iron block "Ls4". My question: Without taking into account the accessory drive, will an LS4 crankshaft physically fit into an LM7 block? I know its accessory drive snout is 10mm shorter than a std 3.622" crank, and the rear is 3mm shorter, But will there be any issue with using LM7 rear main and front seals?


Thank you in advance.

Ill_Born_ss

internally all but the LS7 are the same crankshaft (in dimensions) (materials/manufacturing as in cast, nodular) You will however have to match the reluctor wheel to your computer (24x or 58x)or get the aftermarket electronic adapter. As for flexplate/flywheel you will have to consider the missing difference on the tail.

BoostForBreakfast

Thank you for the verification of that. I figured I might as well pick up an ls4 crank while it's apart, instead of sourcing a new standard crank which I would most likely have to shorten/modify.
And is the reluctor wheel in the same location/alignment as a longitudinal block?

Ill_Born_ss

Yes it is the same. There is/was a couple of guys parting out an LS4 over on gmls4.com in the classified section.

BoostForBreakfast

Thanks for your help

BoostForBreakfast

One more question: I know the LS4 is Gen IV, but are the Rods the same as the Gen IV truck motors (the "better" rods)

Ill_Born_ss

The LS4 rods are powdered metal with full floating wrist pins, they are strong but basic. There are many different rods used in the LS motors and with the exact same dimensions... so to answer, you would have to verify which "better" rods you have.