Actually the exhaust valve that is in those heads (1800runsnew) and in the Merc black engines ( 454/502 Mag) is a 2 piece valve. It is welded in the middle of the stem. It has a stainless stem and an Inconel head. Next time you have one out of the head, put a magnet to it. Inconel is not magnetic and the stainless is. If you run the magnet up the stem starting at the head, all of a sudden it will stick to the stem.
Eddie

I had no idea. Once again Eddie teaches me something new I thought they just ran GM SS valves in black engines and use inconel in Merc Racing stuff.

I found it purely accidental. Those valves are susceptable to breaking at the weld, so I started looking at one to try to figure out what it is made from and why they broke in the same spot. I had a magnet on the workbench one day and it stuck to the valve stem. I was playing around a little later and realized it wouldn't stick to the head. Then I figured out that it is a two piece. It is crazy that you can not tell where it is welded without the magnet. There is absolutely no line what so ever. Whoever does it does a fantastic job. It is actually a good money saver. If they could figure out how to make it stronger, it would be a great alternative to the expensive, heavy Inconel valves. There is no need to have an Inconel stem....only the head. I'm sure they save a small fortune on the valves by doing it this way since the Inconel is over twice the cost of the SS.
Eddie

Make sure you change the bypass valve in your oil filter head or you'll be looking at trouble. Just some FYI

You better call on the price, everyone else is getting $6,700 to $6,900 for the exact same engine assuming this is a true Merc engine.

I did call, 5795. check out the site..www.1800runsnew.com its the same that everybody sells GM BASE MARINE 502

Can u tell me more about this?? It the oiling system routed differently or what?? thanks. I wish there was a How too for 454 to 502 swaps, i thought everything was just a swap over.

If you are running a gen 5 or 6 there are two bypass valves installed in the engine block one for the filter bypass and the other one is for the gm factory remote oil cooler witch is up inside the block where the threads for the remote adapter would bolt up to the block remove the one in the middle. where the adapter is and the one offset needs to be changed to a 30 psi or plugged so all the oil will go throught the filter and cooler.
Dont run the engine untill you have the right bypass valve or you will be removing the engine due to you buring it up like a lot of other guys have done. I spent a lot of research on my set up with the right bypass valve install I'm only running a filter on the block and I'm motioring the oil temp then going from there run a good filter like napa 1061 wix do not run fram they are junk.
Do a search here on bypass valves if you would like to talk to me about the whole set up give me a call @ 734 383-0730 ask for Dale

Back to the valves.
I just took a valve out of a head and the magnet only stuck on the TIP. Do you need a super strong magnet? I just used a telescopic one used to things you drop in hard to get places.

Yes I did check out the website. The prices seems to good to be true. I am in the market for two.

They are the best gm performance parts you can buy. I have one I would gladly send you pic's of the engine in parts whats your e-mail?