Another What Cam Should I Use Post

The 9" will drive you nuts, too heavy, even a 8" isn't light weight. I'd use a spicer 35 out of a Jeep charokee, but I'm not sure of the width. I realize the 9" is cheaper and has the right bolt pattern, but they use them in trucks for a reason.
 
3.55 may be a bit tall depending on your OD ratio. Tire circumferance needs to be figured in also. You probably want about 2000 to 2200 rpm at 70 mph.
The L100 is too much cam for your application.
 
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Depending on which s10 you have assuming a .70 OD and running 3.55 gears at 60 mph you will only be turning 1760 rpm. well below optimum torque.
MPH x gear ratio X 366 divided by tire height x OD ratio.
We have a 5 speed with .80 OD which turns 2080 at 60 which is almost too slow , but flatheads have good torque.
 
I had a T-5 with a .70 O.D. ratio and a 3:54 rear in my '36, it was only ok on the interstate above 60mph. If I were to do it again I'd use a 3:70-3:78 depending on your rear style. I used the stock banjo with open drive conversion. JMO
 
I just went through the same thought process as you. Came to a different conclusion----but I wanted a different effect.

Your car will probably weigh about 3400 lbs. and you only have 239 " to drive it. If you don't want a real "hot lick", don't get too much cam. A 3/4 grind is probably what you want.

On the subject of rear axle-----the 9" Ford is a heavy rear both from weight and the amount of power it requires to drive it. Put a torgue wrench on a 9" sometime, you will be surprised how many foot lbs. is required to turn it. And the ring gear is heavy. A 8" is better but still more than is really necessary. Would you consider the original rear with 3.78 gears converted to open drive?
 
If the cost isn't a factor, check out what Hot Rod Works can do with your original 40 rear. You maintain the original look too. www.hotwodworks.com
WMS to WMS on a 40 Ford is 59 1/2 in. which happens to be the same width as a Ford 8.8 rear.
 
Well now that we've got your attention about the rear end, we can go back to the cam. The L-100 is alittle much for your application . A 239 engine puts out about 80 hp in real life and adding carbs and heads don't do much for low end torque. One of the reasons LONG cams work is because we put them in light cars or big engines. A 276 isn't considered big by some people, but for the street engine it's a practical limit. Now with that much displacement you can get 8.5 CR even with a high lift cam. ALL this increases torque and the L-100 does things we didn't expect and that is run well at low speed in a medium weight car. I have quite a few running in cars over 3000 lbs and the performance below 2000 RPM is surprising. But the big surprise is the mileage in a properly tuned engine. However in your case I'd stick with the stock cam.
 
I've had good luck with the 77b. I had a 50 merc with a 60 over,heads and 3x2 with progresive linkage. I was amazed at the low-mid range power
 
The 77B is very mild and not much more than stock, Considering the cost of running one it's not very effective. Might just as well keep the stock cam. You might want to consider running a set od 81A heads (39-41) set piston to head Clarence at .040-050" this will raise Cr aprox 1 point.
 
When you get enough cam to "rumpity rump", you might not like how it drives.
The next one up is a 1007B.
 
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