Cam selection help

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Mopar85

Mopar85

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I have a 440 with 30 over pistons stock 906 heads, 4000 stall, 3.73 gears and back tires are 31 18 15 back tires. pistions are trw L2266 flat tops. I plan on buying a set of 440source stealth heads in july but want to drive the car now so i need help selecting a cam and speedometer gear for transmission.
 
ANOTHER GD MARINE! LOL! YEA BOY!!!!!!!! Missed ya gettin on board. Welcome. I know your area a bit. Uncle was a lifer.

906 heads.... cough cough...LOL, just JK!
Do you know the overall compresion ratio?

A driver cam now? Hummm, tuff choice considering the stall converter you have now. Normaly I chime in on a cam, but I'm gonna have to say, I'm not sure where to go with this and I will wait for a more exp. guy to come along.

Maybe something in the 236 - 240 @ 050 duration (Intake) and a modest lift.
 
Depends on what kinda stall. Some of the higher end ones drive real good.
 
With that much stall....

MP.590 LIFT SOLID CAM

Now mill the heads and get comp up to a real 10.5 'at least', around 10.8-11.1 ideally.

850 will work good, so will a 950.
 
The way carb selection was taught to me was to multiply the displacement (CID) by the anticipated RPM is likley to turn to. It is important to be realistic when making the RPM estimation. Start by estimating peak power and add 500 for over-speed.so
CID x RPM = ? then divide by 2

that tells you how much air per minute your car uses at peak performance

then to turn that into cubic feet divide by 1728

so a 440 bored 30 over =448
448x7000=3136000 /2=1568000 /1728= 907.407 cfm
is this correct?

so the cam that peaks at 6500 add 200 and that puts me at a little over an 850 cfm
 
I was thinking of a cam like that with the heads you wanna get but thought the stockers wouldn't be handling such a cam considering the work needed for the springs and the stock ort. (If such is the case)

I do carb by CID X's 2, 50 more for strip, 50 more for a manual trans.
For a street car, CID X's 2 maybe minus 50 cfm for a tame or stock build with Hwy. gears.

It's a lame mans way that works well.

440 X's 2 is 880 plus some more CFM for a serious street stripper for me would be a 900 cfm carb at a min. to start with. 950 perfurred. A 1,000 if your going nutz.
 
That works rumble, its in the ball park if not on the diamond=close enough.

Mopar85,That formula is based on what volumetric efficiency?

If you had 100%+ the idea is that you could run less to make the same power.

Like I said....850 will work, 950 will too and maybe better being that it has the venturi of a 750 then the air flow of 950...in other words...it would most likely have better low speed characteristics [air speed/mixing] than the 850.
thats in general, you are runninf 4k stall...so concern about low speed is out the window...not to say it still wouldnt help power, cause it flows more air and through a smaller venturi which should mix things up even better.

nothing to go buy a new carb over, unless you are rich/trying to set a world record.
 
I built a similar package back in the early 90s... I used the Comp Magnum 292H in it and it was excellent. I think I'd say run that, and when you get the better heads and have some higher static compression, then you can upgrade to a larger cam.
 
Some stealth heads are in my immediate future. after july 4th i am selling my honda accord and buying some 440source stealth heads to go with their rockers unless i can find an awesome deal on some victor heads now that 440source has offset rockers for a decent price.
Nothing like selling a gas saver to fix up a gas hog right before i move to California
 
IMO,
No point changing Cams twice, just concentrate on increasing the C.R. later when applying the Aluminum Stealths with some Milling, etc.
especially, with your Tire & gear Combination ?
You are best to pack it all before 6K rpm.

XS282S Comp installed up @ 105-106.
244/252 @ .050", .520"/.540", 110 lsa

Gonna be within 5-10HP of ANYTHING on your Combination NOW with your 906 Irons,
or,
later with the Aluminum Stealths.
 
My calculations on compression with stealth heads with 80 cc chambers +7 cc pistons 4.35 bore 3.75 stroke and felpro. 039 head gasket puts me at 10.46 to 1 compression. What compression can I go to to still use pump gas? I was told 10.5?
 
Are you blueprinting the block or just rebuilding it? Chances are, without blueprinting, you won't be at zero deck. It doesnt sound liek a big deal, and with open chambers it's not. But with the closed chambers you want it at zero. As far as compression goes... IMO the maximum dynamic limit with aluminum heads, a quench of .035-.040, and flat tops is 8.75:1. That will allow pump 89 (w/10% ethanol), at sea level, assuming tuning and machining is done properly. AS far as staticratio, which is what you asked about, that could be 9.5:1 with a smaller cam, or 11.8:1 with a larger one.
I recommended the smaller Comp because IMO it makes better mid range torque and will carrythe rpms well with 906s and do it on mild springs. Otherwise you're going to be spending to cut spring seats and guides down on the 906s to get the right springs on them. Now if you are going to get the Stealths, then I'd replace the springs with the matching Comp springs and run the cam you first mentioned. Just make sure the pistons are at zero deck.
 
The 2266s if i remember are a basic forged replacement for the earlier 440s, they sit around .080" below deck, with a .039" gasket & 90cc chambers, you won't even be close to 10.1, it'll be less then 9.1, so with an 80cc head, you'll be around 9.4 if that, You should have used the TRW 2355s, there the 6 pack pistons & sit around .018" below, with a .039" gasket & 90cc head, the compressions around 9.7, with 80cc, you'll be around 10.3 or so, that would more ideal with aluminum heads, don't know how far in this build you are, you may want to re-think your piston choice if going with aluminum heads & larger cam.

There showing less then 9.7 with 88cc
http://www.jegs.com/i/Sealed+Power/844/L2355F30/10002/-1

Look how low the compression is with an 88cc head.
http://www.jegs.com/i/Sealed+Power/844/L2266F60/10002/-1
 
Mopar85 said:
My calculations on compression with stealth heads with 80 cc chambers +7 cc pistons 4.35 bore 3.75 stroke and felpro. 039 head gasket puts me at 10.46 to 1 compression. What compression can I go to to still use pump gas? I was told 10.5?
Click to expand...

Were did you come up with +7 cc on the 2266s?
 
Mopar85 said:
I found it on a couple websites and they said 7. Is this correct?
Click to expand...

The correct piston volume is that which is measured, not that which is read about. Because of all of the production variances, no two pistons will cc exactly the same, so you need to measure to be accurate.
 
If its a street motor I would go by there numbers. Given the newer technology and tooling advancement.. **** you can make a production Use the manufacturer numbers as a guide it ill be darn close.
 
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