I was wondering how difficult it is to rebuild the lower engine? I am swapping out the engine in my ssei with another l67 that only has 30,000 miles on it, and I'm not paying any core charge on it. So I was wondering how much work/money would be involved in rebuilding the old engine. This would be a project that would span several months due to time/finacial restraints, but after fixing the lower engine I would like to add a few things to it for performance and throw it back in the car. What do you guys think it would cost and how much work would be involved?

I'd think miminum rebuild kit would be around $500

Add in sending the crank out to be checked/turned.
Send the block out for cleaning/boring
Send the heads out for valves/guides etc

A good chunk of work

Some specialty tools like a ring compressor, seal puller...etc..

Could get expensive.. and takes plenty of time to do it right.

But having the feeling of owning a second engine and modding it would be PRICELESS!

Well, a crank kit will cost you about $200 depending on who you get it from. Or, a good shop will regrind your old crank for about $125, and then the new bearings will set you back another $90. If the engine has spun a bearing or has a rod knock, you are going to need to tear it down and clean or have the block and heads cleaned to make sure there are no little bits of bearing material floating around and plugging up your oil system. If you have them cleaned, figure at least another $75. So you will need to remove the heads, and will need new head gaskets $50 and bolts $35. A conversion gasket set for $35 will get you the seals and gaskets you need for the lower end, and you will probably need another $50 in top-end gaskets to replace what you removed in getting to the heads. You will probably want to replace the water pump while you have the engine on the stand $30 and will need new coolant $16, oil and filter $15, and shop supplies $20.

So far, that'* $525+. It is really hard to know where to stop replacing things, and how far to go to keep these projects economical. Once you have invested several hundred dollars, when you find any other worn parts, you will probably feel obliged to replace them. It can get to be pretty expensive just for the parts. These prices are current from: https://www.rockauto.com I have added a few dollars to the parts for shipping (just an estimate), so it might be more or less to ship to you. That'* why we just buy good used engines from salvage yards. It is way more cost effective.

If I were doing it, I would allow a week to get it done. All this presumes that you have the necessary tools, facilities, shop manuals, and skill to make your investment pay off.

I would agree, except, my guess is that it WILL get expensive.