Cam and piston question: is

I have a nice running 1976 440 from a motor home to use as a base for my build. It is still together, and I have been acquiring parts for it’s ultimate rebuild.
What I have so far:
A N.O.S. Sig Erson grind of the magnum cam
MOPAR electronic ignition
440 Source aluminum heads
Holley Sniper E.F.I

I will get headers and duals. I would like to run a Edelbrock Performer not RPM, or a Holley Street Dominator. Perhaps a vintage CH4B? I have a Ramcharger air set up.
The car is a ‘70 Coronet, 727 automatic, 3.23 rear.
I’m not looking at the king of the hill, fastest car in town, just a good driver. My question(s) are this: is there a more appropriate cam, and if so, how so? And what about pistons? I was thinking forged flat tops. My understanding is that I can run somewhat higher compression with aluminum heads

I would recommend 10:1 CR and you should call a couple of cam manufacturers for their recommendations. You can save some dollars by using a cast or hypereutectic piston if no racing/nitrous is in your future. A flat tappet hydraulic cam (much less expensive than a roller) will be fine provided the correct oil is used.
Mike

I would not run a magnum cam in a low compression motor- and today not even in a high compression motor
It's 50 years old
When that motor was new Cordobas had to have lots of heat shield to protect you from Heat- IT runs HOT
It has no low end torque, you have to use lots of throttle to get your vehicle to move- that fuel that is not power is HEAT
Motorhomes and Busses using that motor had short lives-
WE built a special piston for the San Jose CA Bus Company and developed a special cam with the late Bill Jenks at Potvin/ Moon cams
That piston design is now sold by Keith Black
That magnum cam has really long closing ramps which kills the dynamic compression you need with the low compression motor
(to keep the lifters quiet for warranty purposes during the warranty period- later morphed into exhaust gas dilution for smog)
It has sorta long opening ramps giving excess overlap even with the wide lobe centers -opens the intake early
It does not have much lift (area under the curve for flow) for it's duration
What to do
Piston change to the KB's with the quench dome and a short cam will cut your EGT by 800 degrees
no piston change just do a short Lunati Voodoo or the Short Howards showing a (15) footnote in the on line catalog the (15) foot note shows it was designed for a Chrysler and is not a universal (designed for a sbc) cam
The absolute best cam is a custom motorhome grind from Mike Jones depending on the cost and delivery time considerations
all of these cams are mid 250 degree duration @.006 and around 204 @.060 however "intensity" How quick are the ramps makes .050 sor of useless except for installing/ degreeing the cam and a rough cut you want something that shuts the intake around 55 degrees ABDC at .006 (Comp cams has NOTHING nor does ERSON)
The Jones cam has more duration above .200 than the other grinds and in fact is 50% bigger than the Mopar Performance 260 above .275
The Mopar 260 is shorter than the magnum but would also be a better choice with more gear
with 323 stick with the 248 MP but as you can see the ones suggested are more modern
NEW SPRINGS, viton valve stem seals (the two center exhausts run hot) stock rockers will work fine
roller rockers require pushrods and the special B3 rocker shaft relocation kit to work right- read the tech on the B3 website till you understand it
You do not have a truck/ bus application so I'm not showing the MOON Cam

The Sniper EFI works best with a single plane manifold(call their Tech for yourself), the Holley Street Dominator works well.
We built lots of 440's using the ICON 9953 Forged 4032 Alloy Pistons(Cheap) and Stealth Heads(from OOTB to Ported/Prepped), using a range of different Flat Tappet Hydraulic Cams all of which get Run/Tuned/Dyno'd before they are allowed to leave.
Unless you are Porting/Prepping/Altering the Stealth Heads significantly, we have seen no "magic" in Camshafts of similar size lobe profiles on the Dyno for given diameters, ie: .842"/.874"/or .904" and especially around smaller Cams like the magnum where insufficient room exists for great gains specific to a combination.

IMO,
there is good merit in the O.P.'s KISS formula approach, where we typically see 415+hp/500+ Ft/lbs using the 9953's under Stealth's using F.T. Hyd Cams of similar size to the Erson with NO EGT issues.
That said, we see closer to 450 hp/510 Trq just stuffing the no-brainer XE274H CompCam under OOTB Stealths using 9953 Pistons ?
Either way,
The biggest problem you will encounter will be hooking the rear tires even with the 3.23's.

piston IC9553 is great for a 11:1 build with closed chamber aluminum heads

IC 9553 and 9947 are worthless with stock or Edelbrock open chamber heads
FYI found this error in the United Engine catalog

Link to IC9953 shows at the top

Centered pin. Piston IC9947 will be .090" below deck. DIFFERENT PISTON Comp. Ht. IN: 1.991
BVVC calculating CR

Data for SIC9953

2.067 compression height similar to 6-pack piston

692/190 weight- compare to stock for balance

72-11.5, 80-10.6, 90-9.7 compression ratios

WE have extensive dino pulls on short big cams
makes a big difference in torque you can use about 10 degree shorter cam giving you about 5 degrees earlier intake close for dynamic compression

Crown cc: +5.6cc

OOTB stealths/rpm/sidewinder's, zero deck short block - flat tops with 4-6cc reliefs, holley SD - if going TBI. 1 7/8 headers, 230ish @ 50 hyd cam. 11" converter, 3.23's. Great combo, no point in reinventing the wheel on a build like this - IMO.

I don't know where the cc's land these days on Stealth/RPM/Sidewinder heads, but 80 to 84 cc gets 10.5 to 10.2 CR with the 9953s, at zero deck.

justcruisin said:

OOTB stealths/rpm/sidewinder's, zero deck short block - flat tops with 4-6cc reliefs, holley SD - if going TBI. 1 7/8 headers, 230ish @ 50 hyd cam. 11" converter, 3.23's. Great combo, no point in reinventing the wheel on a build like this - IMO.

Click to expand...

Nailed it!!

Unless you are Porting/Prepping/Altering the Stealth Heads significantly, we have seen no "magic" in Camshafts of similar size lobe profiles on the Dyno for given diameters, ie: .842"/.874"/or .904" and especially around smaller Cams like the magnum where insufficient room exists for great gains specific to a combination.

Click to expand...

I agree...... and that’s a good way of spelling it out.

The spec on the RPM is 84cc, last I checked that was true. Probably best to be closer to 10:1 rather than 10.5 with a small cam depending on elevation.

figure out what cc those heads are and do the calculation yourself- you need to have a feel for it
you will need to 0 deck the block with fel pro type gaskets or run the MrGasket .028 gasket
if you do do pistons forget the shot cams I mentioned with 3.23 - maybe still with 2 series gears and not an A body weight depending on how you want to drive
You are still looking at Lunati Voodoo or Howard (15)
The smallest comp XE274HL is still to big unless this is a hot rod, cruz the drive in weekend warrior type usage

There’s a lot of great information to digest here, THANK YOU! I’ll spend the next few evenings going over it.

The bigger you go on the cam the more you have to change the converter
each cam size changes the rpm band and bigger cuts off the line torque
lots of folks like big cam and loose converter but go too far and you have to change gears if driving around town- less so if this is an open road build
know yourself

We use the ICON 9953's with the 5/64" Ringpack lots on cost effective street type builds, those ICON (UEM) guys have stepped up their game of late resulting IMO a very nice piston for the budget, and the much lighter weight vrs the L2355 is usually a nice balancing position.
* Most Blocks with just a cleaning/squaring of the decks parallel to the mainline leaves the 9953 about .010 downhole = ~2.4 CC's
* We use the Fel-Pro 1009 Head Gaskets, but again if budgets dictate then the Fel Pro 8519PT's are an option I guess =~10 CC's (.050" Quench)
* Stealth Heads typically show up here between 82 and 83 CC's, rarely much below 82 = ~82 CC's
* The actual "poured" Flycut Volume on the ICON 9953 Pistons = ~7.8 CC's (almost 8)
________________
Clearance Volume 102 CC's (who cares about .2 CC)

We have NOT seen any advantage on the Dyno, going below .045" Quench on a BB Mopar 4.350" Bore using any base Heads, Stealth, Sidewinder/rpm/E-street etc., etc, and for us it's a waste of time now, given, we could get into a very long discussion around "optimum" quench on a BB Mopar relative to Head Dynamics/Bore Size etc., etc.(NOT going there)

We call it 913 CC's Swept Volume for a .030 over 440 Engine, and then use a baseline static ratio of 9.95:1(10:1) for any other of our other decisions from there, ie: Mill the Heads, Tighten up the Block(quench), elevation, etc.
or...
just leave it there for Cams in the low 60's closing ABDC like the Comp Cams XE274H(63* ABDC Intake Closing for sea levels 91 Octane), NOT the XE275HL, which as I said earlier we see around 450hp/500+ trq using a Performer rpm Intake, and up to 475-480 hp on OOTB Stealth's using a Single Plane Intake.

I mean these are "entry" level Engines afterall ? NO Headwork to speak of really, NO Port Matching, Stamped Rockers, yada, yada.... and typically all done rpm-wise in the very low 5,000's(Comp XE274H)
IMO, best budgets for the automatic guys spent ? can be a "Saturday Night Special" type Trq Convertor ?, although they are reported as just "fine" out of the hole using the stock convertor W/3.55's , and have a nice "you know it's there" Idle note.

Good luck whatever you decide, it should be a nice engine.

Great combo
It all has to work together
I 0 deck the blocks to get the quench down to .040 or less
depending on the chamber it can make timing and fuel less critical but as you say will not show up on a dyno- that's not the point
I do not use cams designed for chevies- period
I many not get much more hp- but I do but I do get more torque and throttle response and less exhaust heat and gas mileage
At least in tow vehicles/ trucks/ busses
Headers are another critical item vs stock or HP (or truck manifolds) exhausts- all can be made to work but exhaust lobe is different
Stock converter w/ 3.55s start there before spending money on a converter- you have no idea what you need till you drive it
HP converter with 3.23 or 3.55
Tough choice with 2 series rear ends as a loose converter helps but you have more slippage at cruse rpm lockup really works here
WE found in testing for Chrysler that 60 ft times dropped with one size larger DC cam than Magnum cam with HP converter (1/8 was quicker) so converter choice is critical
The seat degrees on that 274 cam @.006 is not much different than the 268 Mopar degree Magnum cam but the LCA and timing and Intake close is.
cheers

I ran an "entry level Build", similar to what is being talked here in my 440 71 Charger for a number of years, but with an XE275HL and RPM intake, this is how I found it.
Idle was acceptable with a nice lope, 12 - 13" of vacuum @ 850 rpm, 16" at cruise. Ran OK on 91 at sea level (10.2:1) I had an 11" B&M 2400 holeshot converter, it was a little spongy down low at moderate throttle with the 3.23's but stand on it from a stop and it would push the converter to 3200 and blaze the tires for 100 feet. Very civilized to drive around town and had plenty of get up and go on the open road. Fuel mileage was around 13 MPG. At the track it would run 12.8's @ 110 as it sits, every day street tires, no changes. My car is probably at least 150lbs heavier than the OP's.