I'm looking to replace the 16 valves on my L68 heads on my '68. What I'm looking for is the sizes I need and maybe where to buy them. I've seen advertisements on ebay for 427 valves but not sure if they are the correct ones I need. Any help would be great. Thanks

 

For the small amount of money it would cost to have a reputable engine/machine shop check out and rebuild those heads, why would you want to DIY? If you have to ask the sizes of the valves for those heads, your knowledge about heads seems to be somewhat 'limited'. Why not let a pro...with the right equipment, gauges, and experience...do the work for you?

 

thanks for the reply but i like doing it myself. i don't know about much about the older engines. i know mostly about the ls late models. this is my first go around with removing the heads on this car and found the exhaust valve to be burnt a little and want to replace them. if i wanted a shop do the work i would have asked where to go in my area.

 

You can't just replace the valves.The seats have to be ground. If the valves are shot more than likely you need guides, especially on a big block. Your guides in the head need to be drilled out, new bronze guides pressed in and sized to the stem diameter plus clearance. The seats need to be ground to the centerline of the guides, valves need to be lapped to the seats. The spring pressures will need to be checked and springs reset up with new shims because your installed height changed because you have new valves. All this takes specialized tools and knowedge I would bet you don't have. Find a reputable machine shop in your area and have your heads rebuilt. I like to do it myself also and I have worked in a machine shop doing this work. I do have the knowledge but don't have the thousands of dollars of tools required to do this myself and I hire it done.

 

A picture might be worth 1,000 words here - you "don't know much about the older engines" but you "found the exhaust valve to be burnt a little"?

I expect the valves are fine...but if you start just replacing stuff, you're going to make scrap.

 

You folks are cramping this guy's DIY style.

OVAL PORT - Valve size 2.06" intake, 1.72" exhaust; 3/8" stem.

Manley Street Flo stainless valves with the undercut stems are my suggestion.

#10714-8 intake valve

#10717-8 exhaust valve

Good luck with the head work.

 

As far as I know the guides aren"t drilled out and pressed in. don't you heat the head up and push them out. and then set the new ones? Thats how I remember it done. and then you let them cool? All I was looking for was sizes. already had a friend check out the guides and said they were fine. The only reason why I want to replace them is because there was a little bit of carbon built up. Do they need to be replaced, mostlikely not. But since the heads were already off I thought that I would replace them.

Thanks for the help 69 Chevy!!!!!

 

There's no need to replace valves with "a little bit of carbon [build] up"...and they're certainly not "burnt" with a little carbon. You can easily remove them, get rid of the carbon and put them back in.

If there's any mismatch between the seats and the new valves, you're going to make scrap. At the very least you need to lap the valves just to see what the pattern is.

But, clearly you're going to do what you want regardless - so good luck.

 

Stock chevy heads have integral valve guides. The iron head is the guide material. There are oversized stem valves available and you can size the existing or bore them out and install bronze liners and size them. If your working with 1968 big block heads the guides will need to be addressed if your taking it apart. Big blocks sideload the valves and the giudes are always worn beyond acceptable tolerance on a stock 40+ year old head

 

69Chevy. The heads are off. Now is the time to at least have them checked out to make sure they are OK. The people giving you advice are who I at least trust a tremendous amount. If it wasn't for Billa I would have never gotten through my engine rebuild. He is very practical too. You can find my painful torturous learning curve here on the forum. My 383 engine runs and sounds wonderful, hopefully I will drive the damn car this year and really see what I got. I had my correct heads rebuilt for about $1400 I believe. Not cheap but a really good shop did it. I went to the next size valves. I could have spent the money on new AFR 195 heads and gotten 80 more HP. but I wanted to use the correct camel hump heads, just cheating on the valve sizes.
I still don't claim to know much about engine rebuilds,but you have to know where your at with these engine builds or you will be disappointed. You don't need to spend 10K but there is money that needs to be spent.
Anyway, your no different then the rest of us. Your going to do what your going to do and that is the hobby. If it was easy we wouldn't stay interested. No matter what you do your on the path to the answer, just sometimes the path is longer than it could have been. The forum will support you so don't hesitate to ask and you will learn who's opinions should be weighted more. Have fun and good luck, we all need it!