Thread: Larger engine tames a cam???

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......not sure how to word this, but; I've read where more cubic inches will 'tame' a cam down. In other words if you use the same cam in a 413 small block it will be smaller then if you put this same cam in a 350 small block {all else being equal}.... So lets say a cam is listed as being for a 265 to 400 cu. in small block, has X amount lift, X amount duration & requires a 2800 stall converter. This cam will be 'smaller' in a 400 than in a 350 in so far as lift & durration goes, correct??? BUT does this also mean that the requried stall will be less if this cam is in a 400 verus a 350??? {all else being equal}..... Thank You Bill

Not sure about the stall, but the Isky 30/30 I had in a 400sbc was much tamer than when it was in a 265sbc.

The cam will perform milder in a bigger motor because of the engines ability to move more air...the converter will give a higher stall because the bigger motor is producing more torque. Hope this helps.

Bob
97 LSC
67 Caliente

this is how I look at it.

If you have a .480" intake lift camshaft in, say a 265, it will be radical because thats a lot of lift for a small amount of cubes. But if you took that same .480" lift cam and put it in a 406 small block that .480" is nothing. If you have ever taken a look at some big block cams, the lift on them can be way radical. I've seen street driven big blocks with .600"-.750" lift.

So I guess if you look at the lift on the camshaft, more cubes would let you have more lift, because when you increase the size of the motor, you also increase the size of everything else. Make sense?

rfox is right.To put it in plain talk a bigger motor has a bigger cylinder bore and usually bigger valves.A cam that causes a 283 to breathe deep,due to lift,duration and valve opening and closing points,won't fill the 454 equally or the same volumetric efficiency won't be met due to the larger motor's bore & valve size.Of course there are many variables to deal with when talking about optimum cam timing for any given motor but it's all about what the cam will do to 'effeciently' fill the chambers.

the longer the stroke the more it takes away from the cam,...the shorter the more it gives..........

Exhaust will 'tame' a cam too. I once bought a 400 that sounded awesome in a car with small tube headers and exhaust. When I put it in my car, the same exact engine sounded like a tractor

Be careful when choosing a high stall converter for a street driven car.

Too high a stall, too high the diff gears and the thing will never lock up in normal driving, even at highway speeds.

No lock-up means extra heat generated by the trans - and it can get out of hand to the point where trans damage occurs.

Gas mileage takes a nose dive as well.

....Thanks everyone .... In fact I ordered my cam the other day. I went against pretty much everyones advice & got a smaller cam than suggested {Comp Cams & AFR {I have there heads} said to go bigger, plus a few individuals}. I was just too worried that my stall wouldn't be high enough & I didn't want to have to replace it. It stalls between 2200 & 2600 according to the manufacturer {Calif Performance Trans, owned by Art Carr, who owned Art Carr 15 years ago, before he sold it}. The cam I got was Comp Cams #XE-274H-10, part # 12-660-47, Extreme Energy, 4/7 swap, 230/236 @ 1/2" duration, 274/286 total duration, lift with my 1.6 rockers is .523/.523, cam calls for a 2500+ stall. It's a 413 small block with AFR 195 heads. 750 double pumper. The place that's rebuilding the carb {The Carb Shop in Ontario, Ca.} did say that I picked a good cam as did my engine builder {except he said NOT to go with split duration, but I did}. Anyway, Comp Cams said to go with a 240/246 that required a 2800+ stall, they said with a 413 it'd be good. AFR said to go even a little bit bigger..... I plugged dozens of cams & combo's into my Desk Top Dyno & the one I picked looked best to me. The bigger ones lost a BUNCH of TQ at lower RPM's. I DON'T want that! The last cam that this motor had was either a 222{or 224} / 232{or 234} at 1/2" although the TOTAL duration was 50 more than what it was at 1/2" where as this cam is not. I don't understand this! {old motor put out 499 Tq. @ 4000 & 438 HP @ 5200}. Anyway, so I know that my car will be ok with this converter as it was fine in the previous car with a smaller cam {or was it smaller??? being that TOTAL duration on the intake was about the same.....} I'm going to re post and ask this...... Bill

ps, oh the headers that I have for this car {'32 Ford} are 1 5/8" primaries so they are small. Old car had 1 3/4" primaries.....

More cubes make a cam more driveable, simply because a larger engine can lose more low-end torque and still have lots left. I had a 283 that'd barely run below 3000 rpm, put the same cam,heads, intake in a 400 and it purred like a kitten full of cream.
For a street cam, less is more. You'll spend more time cruising and less cursing if your cam is a little tamer than the experts recommend. In your Deuce, more power than you'll have there will just spin the tires a few rpm faster, who'll notice?

That sounds like a very healthy combination to me, and a really good engine for street performance. Are you going to have it run on the dyno before you put it in the car? I have a similar combination in my '32 and I am very happy with it.

Originally Posted by R Pope

More cubes make a cam more driveable, simply because a larger engine can lose more low-end torque and still have lots left. I had a 283 that'd barely run below 3000 rpm, put the same cam,heads, intake in a 400 and it purred like a kitten full of cream.
For a street cam, less is more. You'll spend more time cruising and less cursing if your cam is a little tamer than the experts recommend. In your Deuce, more power than you'll have there will just spin the tires a few rpm faster, who'll notice?

......ah ha, ok now the 'a larger engine will tolerate more cam' thing is making more sense. Going by the principle of "a larger engine can lose more low-end torque and still have lots left", the cam I choice is perfect.... After I posted this last night I went back to my Desk Top Dyno & rechecked the graphs {also checked them against when member S12493H did my engine on his Desk Top, before I had mine} & with the bigger cam it put out 517 Hp @ 6000 & 502 Tq @ 4500 & at 2000 RPM the TQ was 425, and Tq was around 475 till 3500. With the smaller cam, Tq was 475 @ 2000 {50 MORE then with bigger cam}, from 2500 through 5000 it was NEVER below 500 Ft Lbs. {so at least 25 more here}. And max Tq was at 4000 RPM {don't remember exactly, but something like 520}. The only thing it lost was 12 HP at 6000, in fact max HP was @ 5500..... This is BETTER as I will run 12 in wide slicks {legal ones} so more TQ is a good thing ..... THANKS a bunch, Bill

Originally Posted by rumrumm

That sounds like a very healthy combination to me, and a really good engine for street performance. Are you going to have it run on the dyno before you put it in the car? I have a similar combination in my '32 and I am very happy with it.

.....Yes it's going to be Dyno'ed. I feel more confortable having it all broken in and Dyno'ed before being shipped back to Kansas. Plus if something is wrong with the re build it'll probably let go on the dyno, sort of 'rebuild insurance' if you will...... Plus the last time this motor was built it put out 40 more HP from the first to last Dyno run..... Oh Rumrumm what stall do you have in your '32??? Thanks ;0 Bill

Originally Posted by billlsbird

.....Yes it's going to be Dyno'ed. I feel more confortable having it all broken in and Dyno'ed before being shipped back to Kansas. Plus if something is wrong with the re build it'll probably let go on the dyno, sort of 'rebuild insurance' if you will...... Plus the last time this motor was built it put out 40 more HP from the first to last Dyno run..... Oh Rumrumm what stall do you have in your '32??? Thanks ;0 Bill

I am running a B&M Holeshot 2400 stall in a 700 R4. My 383 has a CompCams Magnum 280 hydraulic (.480/230 @ .050). I wanted to run the XE-274 but it made my DCR too high for pump gas. With AFR 190 heads it dynoed at 450 hp and 468 ft. lbs. of torque. I am very happy with the combination.

.... Rumrumm, Ut oh, an I in trouble??? Quote; " I wanted to run the XE-274 but it made my DCR to high.". Can a small cam change like that change your compression ratio THAT much??? Or is the XE-274 NOT that small of a cam??? But wait, isn't the XE-274 a bigger cam & doesn't a bigger cam lower your compression ratio??? I have the AFR 74 cc heads, what CC are your heads??? Please tell me they are the 68 CC heads!!!
Well you've also got a TQ monster in your '32! In fact, I think I saw pretty much that same combo on the AFR dyno page of their web site? I was going to run the 280 Mag. & then I changed my mind. Everyone except my engine builder recommened a split duration cam. He said that AFR heads flowed so good on the exhaust side that I'd lose TQ with a split duration cam but even AFR disagreed with him. So this REALLY confussed me also....
It looks like are TQ converters are close in stall so I should be good on that one at least..... Thanks for all your help.... Bill