You wouldn't happen to know what this means do ya?

http://img39.imageshack.us/img39/7634/zin8.jpg

Keep finding these Crane stamps all over both heads. This end also has a couple numbers.

not sure on those numbers but I did finally get to check the pistions in mine. yours are the L2399 which is a .095 tall dome, mine are the L2349 which is a .265 tall dome. that is why mine is so high compression with the closed chamber heads. both are a closed chamber style piston so it was not uncommon for people to sway the open for closed to bump up the compression easily.

Hey M/T your book wouldn’t give some other spec’s would it? Like was these motors Roller motors? With floating piston pins? It all just keeps me thinking I’m on to something here. Someone either knew what they were doing or they were just insane.
Took the heads apart today and I don’t think this was a “just slap those heads on there” thing. For off the shelf they picked the right head with the 2.19/1.88 valves and the porting and polishing they have done to all the runners is perfect and the whole chamber is as smooth as glass. Bronze guides. Nylon seals. Shims under the intake springs … wow.
On a sad note the crank is cracked and I had to have the block cut 60 over so new pistons are also in the works. I think I have everything or it’s on the way or it’s at a machine shop. Sooner or later it will all be here and then the fun can begin.

They were flat tappet .I'm not even sure there was a hydraulic roller lifter back then. I belive all the GM rectangle Port heads had 2.19/1.88 valves back then. Not sure on the floating pistons

I'd be sure to have the blocks sonic checked for wall thickness. Older marine blocks have been known to rot out . Had a fresh .060 over 454 split a cylinder wall on me first time out. It was paper thin where it split. Can you just go .030 over?

I've rebuild my share of boat motors and this one is the cleanest I’ve ever seen by far. It came from the great lakes area so it was only run in fresh water and may have been closed cooled being it had a tiny bit of antifreeze in it. Flip the block over on the stand and not even dust came out of it. Even the aluminum intake shows little signs of use.
Also the 427 tall block has thicker cylinder walls and I’ve read that some folks take them .100+ with no worries. I wouldn’t do that to a boat motor but this boat sees little water anyway. It’s not like you are day tripping with it or anything.
Block has already been tested and such and has been cut 60 over. Just waiting on the pistons for the final hone.

why go .060 over,.030 should have been fine.just fyi,.070 over is it for that block in a marine application.

Your measurement was very close, the connecting rod is actually 6.405" c to c.

I wouldn’t worry too much about the 60 over. There is enough block there to cut it a couple more times. Also as I said before the water jackets in the block don’t even have surface rust and are in perfect condition. Also the tall block has thicker cylinder walls to start with. Not to mention that I always flush after every use. You can’t use aluminum around here if you don’t.
After a talk with Bob it seems that we were starting to figure out this motor but we were looking in the wrong decade. Apparently it’s a 1970 (pretty sure on the year) Kiekhaefer 482. A very bad, bad motor. 10.33 compression, 4.25 stroke (welded up 3521 crank and reground to 4.25 stroke), rods custom made by Kiekhaefer (6.405), 4291 heads (intentionally chosen closed port head) redone ported and polished by Crane (the cam people), Aluminum intake also ported and polished by Crane, LS6 pistons, 10qt aluminum finned oil pan. All that was missing was the aluminum finned valve covers.
Bob thinks I should put it back together and then hermetically seal it in a glass box for display. I love this historical stuff and a 1969/70 Kiekhaefer 482 race motor will be a great addition to my 1959 Biese 4pt Hydro Drag boat and as much as I would like to have them both sealed in a glass box I’m more Williamsburg then Gettysburg when it comes to history. Williamsburg’s motto, “Where history comes to life”.

I also found this >> http://www.offshoreonly.com/forums/a.../t-148313.html

I have a old set of 461 small block heads with similar markings on them. I was told by an old school engine builder that back in the day Crane would take new GM castings , port them, install upgraded valves and springs then sell them as "Crane heads" since there where no aftermarket castings back then.

Figured they would be over 10:1 . What was that engine rated at power wise? My guess around 500hp? Will you be dynoing it after the rebuild ?