No, it won't. (Not factory anyway.)
You will have to modify the existing slant 6 mounts to fit it in there, which to me would be a big hassle.
I would just leave your slant 6 k member in there for now and when you convert to the V8 down the road, just put in the V8 k member on the engine and put it all in place from the bottom like they did at the factory. It's surprisingly easy to do, check out my build thread for some pics of how it's done and to see the differences between the k members.
It takes no more than 1/2 hour to do and won't scratch up your inner fenders or trans. tunnel trying to put it in through the top.
Just my 2 cents.
Tom.
