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Discussion Starter #1
Hey guys, I'm looking for advice on this. I bought my 75 back in 2014 and decided to put junkyard vortec heads and a new cam in it, I went through the break in for the cam and everything ran fine for about 200ish miles. then I started having trouble getting it to run and everytime I would adjust my carb to get it to run, the next day I would have to adjust the carb again to get it to run so I got a new one and it ran but had an erratic idle so I resealed the intake and put the fitech 400 on it and that went away. Then around maybe 300? Miles it started shooting coolant from the radiator cap but only when I was driving around and not at idle or if I revved it, so I replaced the cap twice with no luck. I burped it a couple times and it still wont stop. And everything I've read says it's a head gasket so i pulled the passenger side head and found orange stuff almost like calcium buildup all over the inside of the intake and head but the coolant came out clean. It wasnt there when I pulled the old heads.

My biggest questions are what is this orange stuff and can it be cleaned out of the block? Is it worth getting the heads surfaced or should I just replace them? And do you guys think this could be a bad motor or mostly caused by my lack of experience and having only put 300 miles on it in 5 years?

The first pic is where I think air could have been getting into the cooling system but I'm not sure
 

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Ok a few questions? Did you or anyone that you know of ever over heat the engine? Did you do anything to the heads before you installed them? Those questions being asked the first thing I would do is go back and look at the head gaskets. Lay them on the block and make sure all the holes that should be covered Are and the ones that shouldn’t aren’t. Then find someone with a precision straight edge and check and make sure the heads are flat. I have had issues in the past with head gaskets no being correct especially when mixing old with new.
After you check that then we will look further.
 

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Doesn't look like anything but some coolant junk/rust. Old radiators that have had water in them gunk up. That's why they have coolant flushes. Even new coolant breaks down and gunks up. Do a coolant system flush, they sell kits, until the water is clean! Then drain again and refill. Or if you don't feel comfortable take it to a garage and have a flush done.
 

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That looks normal to me.

Was the engine overheating? Usually you'll see evidence of steam cleaning in the chambers and corrosion in the exhaust port if coolant is coming in.

Kev
 

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Discussion Starter #5
I dont know if the previous owner ever over heated it but I know the last time it blew coolant it shot up to 260 but I shut it off and it was still hotna couple hours later. The heads I had cleaned up and the shop i took them too told me they were flat so i didn't have them surfaced. I laid the gasket back on the engine and all the holes were open the only ones I'm curious about are the coolant holes at the top of the block, they are like quarter size on the engine but the gaskets have tiny holes, is this right? Pic 1 and 2 show them.

There is one coolant hole on the heads that is blocked by the intake could that be a problem? It does looks like coolant was pushed past the intake gasket on the head side of it.

I already have a new radiator and water pump so I'll get the block cleaned out and the chamber dont look too clean but I'm not 100% sure what it would look like from steam cleaning but there is no corrosion in the exhaust ports.

I will take the heads to a shop and have them looked at, I found a crack today around a bolt hole.
 

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Looks like mismatched parts to me from the pictures you posted, but you are so zoomed in it's hard to tell. Give infor on what your engine setup is and a complete picture of it too.
 

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Can you take a picture of the deck on the block? You may also want to check the deck surface to make sure its flat?
 

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Can you take a picture of the deck on the block? You may also want to check the deck surface to make sure its flat?

ANYTIME i build a motor i deck the block and shave the heads
I also have a machine shop at my disposal for free.
I trade out a/c work to the owner for all my engine building needs
 

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Discussion Starter #11
From what you guys are saying it sounds like my rush to get it running and skipping getting the surfaces leveled caused the issue. The one head is cracked around a bolt hole so I'll have to replace it. I'll have the engine cleaned and decked before I rebuild it and I'll have the new heads surfaced as well.

The only think I'm uncertain with is the head gaskets. Do they all have just the two small holes for coolant? Or are some the same size as the coolant passages? Thebones I'm talking about are the two little holes at the top surrounded by buildup in the second pic.

Thank you guys for your help, I wont skip steps next time.
 

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