Assuming the 36-68 number on the camshaft is the timing event, then that would make that a 284° duration camshaft.  A micrometer check of the lobes would give a lobe lift value which could be converted to a valve lift value by multiplying by the rocker arm ratio.

Those pop up pistons will work with the ‘471’ casting heads and be pump gas compatible.  The '471' heads are still big valved but have combustion chambers in the 82cc range.  On the other hand, those pistons can likely have the tops machined off and be used with your existing ‘G’ heads and also be pump gas compatible.  This would require a rebalance of the rotating assembly though.  You would need to cc the heads to confirm their combustion chamber sizes so that an accurate compression ratio determination can be made.  69cc was the nominal value for the ‘G’ heads but they can be larger than this before any milling has been performed.  Based on the code date on the pictured head, it’s an unposted head which means checking the measuring pads on the exhaust sides of the heads and see how much they have been milled.  Unmilled heads will be 1.000” at the pads give or take a few thousandts.  The factory did not recommend milling beyond 0.010” on the unposted heads but supplemental posts can be added to the heads to improve head gasket sealing when the compression ratio is raised.

Lorena, Texas (South of Waco)

  Ted,Thanks for chimeing in.I was hopeing maybe the 113s would work or like you said maybe trim the domes.I have a set of 113s.Although it would be nice to use the ported heads that it came with.On the heads measured I am reading 1.001 on the pad.I have checked most of my heads I have laying around and most measure in 1.007 range or slightly less.I am not sure if this is because they are Canadian pieces?Or is that a common stock height.
    How does a guy go about figuring out the cc of domes?Upside down in a beaker and try to measure liquid displaced?It would be nice to figure out dome size.I see the Mummert pistons are 10cc domes,I don't know if I'd want to shave whole dome off but if I could get them to a similar size maybe.
    Roughly how much comp is lost with composite head gaskets?This engine had steel gaskets in it.There is a 7 liter Galaxie running doubled gaskets in it to reduce some compression.Are there thicker gaskets available for Ys?I warped a head on a 5.9 cummins once and that was what we did to return to spec after heads were planed(.050 gasket).I don't like the double gasket idea but is there a similar option?
     I'd like to try and use everything that came with engine to maybe preserve it as it was,and possibly keep rebuild cost minimal if possible.
Thanks Dave

OldMics
You had better luck than me,I could hardly find anything other than Potvin ground they're cams.Checked the barn,Hamb,here too.Searched everyplace I could think of.
I did come to conclusion it was built a long time ago!

I was in town today so I took the girl in with me,didn't know that a cam profile machine existed...

   Ted,can chambers on the G heads be relieved enough drop a bit of compression and increase the flow.It has stock size valves still installed.I was wondering if opening up chamber by unshrouding for say 2.02,1.60 combo and some relieving of flat side around exhaust valve,perimeter of intake seat faceing outwards and possibly around spark plug side all the way across.Could I shave enough cc`s to make a substantial difference and improve flow of chamber?The piston domes need to be measured due to the fact they have a hollow spot under dome and cannot be cut clean off.
    Thanks Dave

While I am sure that report was done in good faith - there are some things that I would question.

Did you actually watch the test proceedure being done? Which lobes did he actually take measurements from?

Oldmics

He was pretty busy did it in a little bit of a hurry.But for free,it is very close I would think but not exact.Close enough to figure out its mostly ridicullously huge.And he charged nothing to look quick.
Dave

The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked.It would be real close,he saved the info for future.

Exact specs aren't that important.  If that's in the ballpark, then It's too big for street use.  That engine probably won't even start to run until 2500-3000rpm.



Lawrenceville, GA

Well the old saying is...one in hand is better than 4 in the bush.Funds are not high right now,so we'll see.Likely put it in for now.Don't have the money to buy another one.