I have a 360 engine stock, just been rebuilt, in a 76 ford truck.
If I have the deck milled. It has flat top pistons with 4 reliefs.
How much should I mill the deck? Should I go to Zero? And what
will I have to do to make the intake work? I want about 9.5:1 compression ratio. I want to run pump gas. Thanks, Duane.

 

I'd say build it to a 390. The increased cubic inches will give higher compression, and more hp / torque. All you need are 390 crank, rods, and pistons. Aftermarket flat top pistons help too.

 

Dberg, if you have a 360, getting a zero deck is almost impossible. That is one of the reasons that the 360 isn't nearly the performer a 390 is. the extra stroke of the 390 helps a bunch, but the 360 also suffers from way too much deck clearance. You are correct, a zero deck is ideal. But the 360, with 1.75 tall pistons, 1.75 throw, and 6.540 long rods, only has an assembled height of 10.04. This in a block that is usually 10.17 tall. That gives you a deck clearance of .130- too big. Ideally, you want .030 to .060 clearance at the top. Even if you milled .100 off the tops of the decks ( which is double the .050 I consider the max ) , you still have the pistons .030 down the hole, which, with the .041 thick gaskets most guys use, will leave you with .071, too much. Truthfully, decking is one of the first things that should happen to a block, and then, only if you need it- like to correct warpage or damage. If you do deck the block, the whole engine will have to be dissaembled to do it. And after decking the block, the intake manifold won't fit correctly, as you have already imagined. Some folks like to mill the intake to correct this, but I would consider that the wrong approach. If you are already shaving the block, you can shave some material off from the top of the block on the at the front and the back. and you can shave some material from the intake face OF THE HEADS, rather than the intake itself. But afterawhile the dizzy won't fit right anymore either. So heavy milling really adds to the complexity of your build- and all of that machining is exspensive. It might be cheaper to switch your crank and rods for 390 pieces and get closer to zero that way. Is your engine already assembled ? What brand and what part # pistons do you have ? Is is much easier to get close to zero in the 390, and you get the extra stroke to boot. Have you run this engine yet ? DF

 

DF, What if you went with a 7 inch rod and a short compression height piston to get zero deck? The long rod would give a 2:1 Rod/Stroke ratio. The long rod and zero deck should give good detonation resistance. Any thoughts on how high a compression ratio you could go with this combo? Power output guesses?

 

Good idea, but where are you going to get the 7" rod?