help quick!! cylinder head problems....

[4x4orbust]

so this weekend i decided to pull the old manifolds off and replace them with headers.    turns out this was a bad decision...

1:    i couldn't get the passenger side exhaust manifold off, and broke off a couple bolts while trying to remove them.   no problem, drill them out and re-tap, right??  not so easy.   as i was drilling out one of the bolts, antifreeze started pouring out the hole.   are these heads no good now?   

2:  i recently found that my block is from a 70's car/truck, and i just so happen to have a 73 gmc with good heads at my disposal, can i swap the heads from the 73?   

3:   is there any way to tell if the current heads (the leaking ones) have had any work done to them?   the drivers side head is still good on the truck, but the passenger is the problem,  so i was hoping to be able to just swap the passenger side head with the one off my 73.

this truck has been nothing but problems since i started working on it,  so i should have known this wasnt going to be as easy as swapping on some headers.....
thanks for the help

[VileZambonie]

I stopped reading after you drilled into the cylinder head and coolant poured out.... time for new heads

[4x4orbust]

ha ha, it was kinda winded.  i already took the engine apart to put new heads on it, got it down to the cylinders now (one side only).   gonna take the heads off the 73 tomorrow.
as it sits now...

[4x4orbust]

well, i ended up pulling the heads off the 73, to find cracked valves.  went to advanced to find out how much new ones would be, and met a guy there that said he had some heads at his shop,  went down and looked at them and they were reman'd with little use.  nabbed the passenger side for only $50.  Installed it and put the motor back together and she fired right up. 

one question though,  i put everything back on just like it came off, but the motor seems to be lacking in some power.  as i was backing it into it's spot, it wouldn't climb over the 6" lip, even when floored.
  before the teardown, it idled nice at about 6-700 rpm's.   after i put it back togerther  i had to adjust the idle screw in about 1.5 turns to make it idle at 7-800 rpms..  could it be that the timing is off a little?   not sure what the timing is set at right now.  any helps

[355shortbed]

just my 2 cents but i always like to use cylinder heads in sets, i would have bought both remans and installed them together.. one head can be different than another in say..port shape , chamber size, valve size..so on and so on

[4x4orbust]

i did bring my old head with me, we matched the old one with the reman'd one, they were the same.  (they are both stock heads)  he referenced numbers from both in a book he had and they showed to match.

[VileZambonie]

yeah check your timing

[bigblue09]

how many miles are on that motor?

[4x4orbust]

not many,  i was told by the P.O. that it only has about 5-10k miles on it since the rebuild/bore (.030 over).  when i removed the head i could still see remnants of the crossthatching on the cylinder walls,  so definately a low mile motor.     the tranny and transfer case were done at the same time.  i'm going to be checking the timing this afternoon.  it may just be the 3.08 gears that make it feel like a dog, jus tseems to be lacking some serious power to me.