You stated in your OP that the engine has about $3k in it. At that cost I would assume that the pistons have been replaced with something with higher compression. That being said you should try to identify the pistons. Any chance you can get the receipts?

First issue. The heads you are looking at are cast iron. If bolted on to an engine with higher compression, there is the possibility of detonation. The chance is lessened with flat top pistons but if it happens you are forced to buy expensive gas. Aluminum heads really help on this problem.

Second, be very careful when buying rebuilt heads. Some shops will "shave" the deck too far to get them straight or raise the compression. If too much is removed you can have problems with intake mounting or valve clearance. Ask the rebuilder how much was taken off. Whatever head you choose to buy, check the valve clearance when installing.

Third, you did not mention if the engine has an aftermarket cam. If the cam has a higher lift than OEM or higher ratio rockers are installed the heads may not support this combination. Also, the ad says "guides replaced as needed" I would request all guides replaced and trimmed for extra lift. (Another question for the rebuilder)

Not trying to rain on your parade here. Just don't want to see any money (or engine) go to waste.

 

alright thanks for the advice, i'll be looking into that tonight for sure!

 

alright, so i had a few friends of mine looking over the engine im going to build and they all seem to think that the pistons in it are either 10:1 or 10.5:1 flat tops, if this is correct, should i go with the 64cc chambered heads so my compression isnt too high, or will the 58cc chambered heads be fine? thanks

 

Did they say why they thought they were 10 or 10.5 ratio? That's a tough call to make by just looking at a piston, even for a experienced engine guy. I'd want to take the numbers off the pistons (if they are marked) and check the actual ratio before just guessing by "looks".
Once you've done the rebuild or engine work, it's tough to go back.

 

i cant remember why they thought this but one of the guys has a ton of experience building engines but another guy did suggest i look up the numbers to make sure, should i be looking inside the piston?, and another thing...the heads that i posted in the beginning, i'm probably going to go with the 194s as of now but i called about the valve springs to make sure they'll be able to handle the lift of an aftermarket cam and it turns our they're stock springs, so i was looking around and found a valve spring kit from summit which can handle a max lift of .550'', it includes the retainers, locks, seals, and obviously the springs, i was wondering if anyone would happen to have an idea as to how much a shop would charge to have the valves replaced? thanks!

 

It's not tough to change valve components if you get a spring compressor. You can rent them cheap, or maybe your friend who does a lot of engine work could loan you his?
Most machine shops will charge an hour shop rate to change the parts out, but if your heads need guides, or other work that would be extra. An hour can be anywhere from $50-$90 per hr.

 

alright thanks a lot for the info, i appreciate the help!

 

Why not just contact the seller and see how much he'd charge for a valve spring upgrade,shouldn't be any big deal for a guy that's doing heads all the time and he can likely get parts for less than you can if he doesn't already have a set in stock.

 

i'm on it right now....just messaged the seller about that, after looking around i thought why not see if they can just swap out the springs themselves, but how do i know if they really did switch them?

 

When you're buying over the internet you never know what you're going to get. It's all up to the seller to either do it right, or cut corners, or even outright lie. Need to check their feedback, and steer clear if they don't have lots of positive feedback.
As for being able to determine if they did it after you receive the heads; you can have the spring pressure checked on a spot check locally, or you can look at them. Almost everyone uses double springs for any high performance head, but a few aftermarket head builders do use a single spring especially designed to do the same. Ask the seller what springs he uses when you ask if he can upgrade them.