First off, I dont know much about engines at all. But after hearing a bad knocking noise coming from my eninge, my mechanic told me that one of the crankshaft bearings is spinning and im going to need a rebuild. I have an 88 with a 5.7L.
Is there any way to make my engine more powerful without paying too much more than i would when rebuilding with factory parts?

 

The parts you'll need to replace aren't really the parts that make the power. You could put a different cam in, power comes from the heads.

 

im also going to be replacing the heads because the mechanic said its not much more and theyre worth replacing...

 

Well, it's considerably more money actually, maybe close to a $1000.
You can just port the current heads a bit. The cam would probably be your best bang/buck right now. $250 or so.

 

if its a crank bearing and not a rod bearing-line honing cost big dough

but I have no idea how anyone could tell the diff in bearing knocks

you may need a crank too.

so before you start spending money on performance upgrades I would get that motor out(hint-do not drive it anymore) and take a look at the goodies inside

 

Align honing doesn't cost that much.

If it is a bearing, the chances are about 95-5 that its a rod bearing rather than a main bearing. You could call either of them "crank" bearings.

 

ok, i guess ill get a short block rebuilt(without the heads). But ill get them ported. I hear that will cost $400-$600. What should i tell them i want when i tell them i want a different cam?

 

In my opinion porting stock heads is only worth it if you do it yourself. I can't speak from personal experience on home porting because I've never been able to bring myself to go through all the time and effort to still fall short of the flow #'s an out of the box aftermarket head will give. If money is limited and you have the time to do it I can't argue with the bang for the buck that porting stock heads will give. But to run any sort of performance cam you also need to get screw-in studs and open up the valve spring pockets for performance springs.

 

Yea, you really have to port you heads at home or else it's not worth it.
I spent:

$60 - 1/4 300W die grinder, single speed
$30 - parts to build speed controller (ceiling fan ****, electrical outlet box)
$60 - assortment of carbide burrs from www.carbidebur.com
$20 - sandpaper rolls and arbor from mcmastercarr.com

Then I just ported them up real nice. I'm still using 1.25" OD springs, and didn't have to modify the heads for my valve lift. You can always just touch your guide bosses with your angle grinder.

Look at a cam like the compxe264HR or thereabouts.

 

I guess ill get a long block rebuild with new heads and all. Its gonna cost about $2800. If i got a better cam, would i need to get performance springs or will a cam by itself be ok?