hi i just bought a 74 440 rebuilt with steel crank .stock rod .complete flat top pistons, the heads are rebuilt 906 .stock,was bored .030 over my piston to top of block is .118 .i am looking at a crane power max cam with 450 to 480 lift or edle brock idle to 5500 .i will be putting a 2400 stall converter ini now have stock hp exhaust manifolds may put headers on .it has edelbrock idle to 5500 intake with 1 750 carb.could any one give me a idea on hp compression.and tourque .it will be a street car  

If the pistons are .118 thous. in the hole your comp. will be around 8.0/1 to 8.5/1. This will not make for a high horsepower engine, especially with the open chamber 906 heads.
Be sure the 906 heads have hardened valve seats, other wise the exhaust seats are going to crack and lead to problems.
Horsepower guess? Good question, but with a 450 lift cam and the low compression, I wouldn't expect more than 325HP.  

The doc is right, 325-maybe 350 at the outside. It's going be a let down thinking you've got a Crane cam, Edelbrock intake and so on to find you're engine does not really make any more power than a good completely stock re-build. The right way is to replace the pistons, but you no doubt feel locked into the finished short-block. I come up with 8.22 c.r. w/ no valve notches and the usual Fel-Pro gasket. Crane calls for 8.75 to 10.5 w/this stick. For a 440 this thing will have a soggy bottom end. There is a partial cure that will help a lot though. You can easily take .060" off the heads to get the comp. back up there. Take .050" though to leave room for a few rebuild surfacing jobs if you want to keep these heads long term. This will get your chambers down to around 77 cc's, giving you about 8.9-1. Be sure the shop takes .0123" for each .010" off the deck to maintain intake port and bolt alignment-about .0615" for a .050" shave. Also, rather than the 4.41"x.039" Fel-Pros, you can run the MP 4.44"x.020" gaskets, which should get you up to around 9.25-1. Together, this will make a big, worthwhile difference. Many don't like the MP steel shim gaskets, but they are what the factory used, and with freshly machined deck and cyl. head surfaces you should be fine. Coat the gaskets with Hylomar and torque them down carefully in steps and be glad you have made the best of a non-ideal situation. The rest you can make up for by messing with the advance curve. While the heads are apart for the surfacing, you might consider a bowl-porting job using the MP templates. If you tackle it with a die grinder yourself-be the air and fit the templates in carefully as you go creating as smooth and gently radiused forms as you can. Or have a good shop do it-but you might want to compare their cost to a set of Edelbrocks at that point if you want to go this far. If you have a good hand though and can DIY, the porting and compression should be worth at least 60hp and some good bottom end torque over just bolting it all together as is. This should help a bunch in giving you the strong 440 that you envisioned.  

I actually did exactly the same thing with my old 440.  My pistons were .080 thousands in the hole and were flat tops. I took .60 off the 452 open chamber heads & ported & polished the heads with 2.14/1.81 valves. I also installed thin steel gaskets, all this added to a huge increase in horsepower.
With a 292/509 cam my B-body 440 street car ran 11.90's at 114 mph in the quarter mile.
So as you can see, machining the heads surface to increase comp. really does work.  

I did that with my 906s too and it really woke the car up. I was using the old Crane .504x.528 Commander and it was sure a lot happier around 10-1 than 9-1. I would suggest going with the headers too and 2-1/2" min. exh. system. If you are using the Performer intake instead of the Performer Rpm, at least top it with a spacer for a little more plenum volume to help you up top.  

thanks for the info i am looking at replacing the pistons with keith black dome pistons . i am looking at compession in the high tens ,how much more hp will i getwith these pistons  

Your horsepower will depend on many factors, however upping the compression 2 to 3 full points you can expect a solid 60/75 hp gain.
With the increased compression you will need a strong cam, intake, carb, heads and headers.
It is quite easy to build a 500+ hp 440 today with bolt on parts.
With a 10.5 comp. the 292/509 is a great cam.
750 or 850 d.p. holley.
Torqer or Performer RPM intake.
1 7/8  headers
Ported and polished 906 or 452 heads with 2.14 intake valves and 1.81 exhaust.
With the 850 my 440 with the above combo made 525 H.P.  

Good deal, glad you're willing to tear 'er down. Definitely go up on the cam like above or something comparable if you are giving it the compression it needs. The Crane you were considering is very mild even in a 383-the 440's appetite will make it seem that much smaller. Plus with the higher comp. and small cam, it will be harder to run any kind of decent ignition advance because of the high cylinder pressure at low rpm. The ported heads really are worthwhile too.