Is it possible to run a 440 with 11.1 pistons and iron open chambered heads on pump gas?

Any ideas what cam to use to bleed off some of the compression to help?

How good is your pump gas I ran 12.2 to 1 on the street with 906 heads on 94 sunoco @ 33/34 deg total timing was fine.
But I had a 4000 stall. Where the motor loads is part of the equation as RPM's go up octane requirements lower. (gas burns a constant speed and events speed up) richer mixtures also burn slower than lean!

800 double pumper.

The cam was an ultrayne 263/271 duration @ .050 108 lsa installed at 104.5

At the track I needed a 50/50 mix of 110 and 94 to get best runs @ 39 deg total timing (NO VACCUUM ADVANCE)

the vacuum advance even on the proper ported vacuum can cause drivability issues at light cruise on a higher compression motor with lower octane fuels.

tell us more about what you have we are not clairvoyant.

I'm thinking a minimum of 4000 stall and 248 @ .050 duration! Hydraulic or solid in your plans??

I'm running 11.2:1 but with Aluminum heads. I did have an 11:1 closed chamber 440 that ran well on pump gas (93), I did however have and still do a meth/water injection kit. As far as bleeding off compression I guess you could always drop a 484 cam in it..lol I wouldn't worry too much about it. Keep you timing under 36* and you should be fine.

google "atkins cycle engine". It was originally in a MRM build decades ago & they used very high compression & a special cam to bleed off enough psi to run regular gas with a phenomenal increase in gas mileage in a chebby truck (dont remember if it was a SB or BB but iirc it was BB). The trade off was a loss of mid/high range power. Something about the cam timing events that gave the benefit of high squeeze but lowered the actual CR so as not to ping & that sounds conflicting but that's what the deal was so yeah check it out & go from there. I'd like to do a 318 mileage build with it

I would feel better using a closed chamber head and building quench in the eng. If your budget would let you an alumimum head would be good to use as the closed chamber will bump comp a little. But I would rather run a bit more comp with quench then less without quench. As was stated if you do it the way you want you might have a lower rpm dog if you use to much cam for what you have. Ron

I run 12.5 with Stealths in my 440.It did have reworked 516s.I can run on pump gas allday.Only time I have any problems is under a real hard load.At the track I run 112 octane.Its driven quite a bit in the summer.A lot depend on the cam and timing also.Mine has 36 degrees all in at about 2200 RPM..If I backed it off I probally would get no clatter.Rocky

This engine isn't togeather yet so knowing the actual compression is up in the air yet but the pistons are .030 over and have a good size dome on them and they are older TRW's I was told by another local Mopar fellow that they were 11.1's, so that is all I have to go on at the moment.
This engine is stock stroke with this .030 over bore so it isn't anything fancy.

A friend of mine bought the complete low milage rotating assembly that is ready to bolt in and he wanted to use them instead of buying new lower compression stuff.

Pump gas around here is 93 octane and he is wanting to use a small hyd cam in the .484 range with a small stall around 2200-2500 range along with 3.23-3.55 gears.

This is going to be a street only engine and I originally thought maybe he could use a wide LSA cam with alot of duration to make it more livable.

If it means anything he is wanting to use a 6 pack setup he has on it as well which should be fun dialing in.

if that's a mopar 484 cam it will not like that low stall and gear. I always thought the TRW's came in stock, six-pack (10.5:1) and the domes were like 12.5:1 The six-pack pistons are flat tops w/ the notches.
6-packs aren't hard to tune, if I can do it anybody can.

I'd bet with a fel pro head gasket and no (or very little)head milling he will be at 11 to 11.5 to 1.
The dome is not that big after you take into consideration the piston height is about .050 down the hole and the valve trough.

I ran those pistons in my 440 906 head motor for one season with a .039 fel pro head gasket and .065 milled off the heads with a big hydraulic cam (the mopar .528 320 duration (272 @ .050??)) and a 4000 stall. Could only run about 33/34 total timing without some race fuel mixed in.

with a small cam and that way tight converter he is looking at ping a mopar 484 (degreed in properly) with a 3500 stall (no less than 3000) he may sneak by with 32 degree total timing!

That compression is going to want a cam and then the cam will want a converter!!!

Has he thought about edelbrock heads will make it more fuel friendly and more pop to boot.

If its a dome like on the 2295 TRW/Sealed Power pistons, 90 cc 906's, .040" gasket, and 0.050" in the hole, you will be closer to 10:1.

There are a few tricks you can do with the heads to lower your compression ratio, and since your engine isn't together these can be done easier. First, use tulip valves in both the intake and exhaust. Second, un-shroud the combustion chambers around both valves out to where the head gasket fire ring is. Third, polish the combustion chambers. You can even, un-shroud where the valves open into the cylinder, again use a used head gasket as a template (to locate where the fire ring is after it's compressed) and go no farther into the cylinder than where the top ring rides. (pic). When assembling the engine use the thickest head gasket you can find.

Thanks everyone for the information. I will pass all this along to him so he can plan this build out before actually bolting everything togeather.