Inliners International Forums General Discussion Hi Performance Cam number and head milling

Hello to all I have been lurking a while but never posted here. I picked up a chevy 250 cam a while back and I was wondering if anyone knows the specs on it. I have done an internet search and yeilded nothing. It is a Crane cam and the grind number is HMV-272-2-NC. I have found other grind numbers for 272 cams but not an exact match. My second question is does anyone know about how much to mill of of a 72 250 head to get somewhere around 9 to 1 compression on a 250 with .020 over flat top 307 pistons. I will be running with an Offy manifold and long tube Hooker headers in a 72 Nova with a 4 speed. I have had this car since I was 14 (now 33) and have been storing it sinse 1990. Thanks for any input on this great board!!

For the cam, I would call Crane cams.

With 307 flat top pistons w/four valve reliefs. I believe it should bump up your compression roughly one full point over stock,(going .030 over) which stock compression is 8.5 to 1 yes ,,no? That's off the top of my head.
That is also useing a steel shim gasket. Like .025 thickness??

Head gaskets vary in thickness..038 some Felpros,Corteco close to the same.

So it should be about 9.5 to 1.
It all depends on you combustion chamber size(how many cc's it is)
How far down the hole your piston sits @ TDC.
Head gasket thickness and so on.

How fast do you want it to be?
HP???

That sounds like the newer Power max which replaced the Other HMV 272-2 which is a 530/560 gross lift Dur.@.05 216/228 .000valve lash hot in/ex with a 112 degree lobe separation RPM band
2000-5000 cruise rpm 2600-3000 8.75 to 10.5 -1
So this would have a good idle daily usage.

Thanks for the input! I bought the cam for five bucks because the guy couldn't figure out why it was so long. I have not tore the engine apart yet to check the head but I have at least 12 engines to chose from if I don't like that one. I am just wanting a driver at this point so I am guessing about 200 horsepower or so. Nothing fancy.So I guess it sounds like I will not have to mill the head to get what I want. Twisted, What are your thoughts on lumps at this level? or should I just do a good valve job with a back cut on the valves. I will be doing all of my own machine work with the exception of the cylinder boaring. The reason I ask is I can never leave anything alone and will almmost certainly try to get more out of it after a while. Thanks!

Point Blank They won't hurt!! there is a gain even with the stock valves.

You need to look up the head casting number to get an idea of what size the chamber is.
Or measure it yourself or have it measured so you know for sure.