Camshaft Selection

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1971 Mustang Sportroof M code
Attached is a spreadsheet that I have been playing with for a while, that is designed to give the user a starting point for selecting their camshaft.

It also provides a starting point for torque convertor stall and carburetor size.

It's also fun to just play around with, to see what happens when the variable are changed.

If anyone sees anything that doesn't look right, or a value that seems unreasonable, please let me know.

EDIT: Spreadsheets updated 9/29/2016 (thanks to jbojo)

EDIT #2: The duration shown in the spreadsheet is for advertised duration, NOT for at 0.050" lift.

Cam Selection-V2.xlsx

Cam Selection-V2.xls

 

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  • Cam Selection-V2.xlsx
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  • Cam Selection-V2.xls
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Last edited by a moderator:
Don I have booked my car in to a garage to have the engine pulled. The car has done 93,000 miles. I know it will depend on how hard its been driven by previous owners as to how good or bad the guts of the engine will be. So i am thinking to replace the guts of the engine with like for like. I wont know if it needs a rebore or oversized pistons till the engine is stripped out.

I also want to replace all nuts and bolts when the engine goes back in.

Do you sell what i need? Or can you get what i need for me?

 
Attached is a spreadsheet that I have been playing with for a while, that is designed to give the user a starting point for selecting their camshaft.

It also provides a starting point for torque convertor stall and carburetor size.

It's also fun to just play around with, to see what happens when the variable are changed.

If anyone sees anything that doesn't look right, or a value that seems unreasonable, please let me know.
Nice, I tried both and the second one gives me an error for torque converter stall. Is there a difference between the two?

BTW the numbers for my motor matched up with the output of your 1st xls. I guess I got it right with the cam selection and torque converter.

 
Don I have booked my car in to a garage to have the engine pulled. The car has done 93,000 miles. I know it will depend on how hard its been driven by previous owners as to how good or bad the guts of the engine will be. So i am thinking to replace the guts of the engine with like for like. I won't know if it needs a rebore or oversized pistons till the engine is stripped out.

I also want to replace all nuts and bolts when the engine goes back in.

Do you sell what i need? Or can you get what i need for me?
Sorry, wrong Don. You'll have to contact Don at OMS (Ohio Mustang Supply).

 
Nice, I tried both and the second one gives me an error for torque converter stall. Is there a difference between the two?
Thanks much John, I found two errors, one at the lower end and one at the upper end of torque converter ranges and updated the spreadsheets. I used xlxs to put it together, and then converted to xls. If you still find the same error, let me know what parameters you were using when you got the error, and I will dig into it.

BTW the numbers for my motor matched up with the output of your 1st xls. I guess I got it right with the cam selection and torque converter.
More like I got it right :)

 
Don,

this is what I see when I use the 1st and second links for the xls in your original post. This could be on my end but I am not sure. Wonder if others see the same thing.

006.jpg

007.jpg

 
Don,

this is what I see when I use the 1st and second links for the xls in your original post. This could be on my end but I am not sure. Wonder if others see the same thing.
They both come up correctly on my computer, which is why I posted both versions so that one of them, at least, should work for everyone.

Thanks for taking the time, John.

 
I tried it and it would appear to be pretty close if the duration recommended is advertised duration.
Thanks Jeff, good point, I should have made that clear in the description. I'll do that for the next version.

Yes, that is for advertised duration.

 
Quick question on this. Am I correct in assuming this is more geared toward flat tappet than Hydraulic roller?

Here is why I ask. I have attached the sheet calculation as well.

After numerous phone calls to several different cam manufacturers and a local engine builder that is familiar with Clevelands I came up with the following custom grind for a full roller set up from Comp Cams....

73' 351C 2v stock bottom end. Aussie 2V CC heads, long tube headers, Holley street dominator single plane intake, 750 CFM carb, pertronix III, 3.70 trac lok, 5 Speed manual.

608/612 Lift

225/232 Duration

112 LSA

Obviously the duration is considerably less than the spread sheet but the lift, if I understand correctly, makes up for this. The custom grind they quoted me includes matched valve springs lifters, etc. Does this seem right? According to comp cams guy he assured me that this would still make vacuum at idle and make power from the 2000 - 6500 range (not that I plan on spinning the car up to 6500 often).

Any thoughts would be appreciated.

cam.JPG

 
I believe the durations they gave you are at 0.050" lift, not advertised or total duration. For instance, Comp Cam's hydraulic roller retrofit that has an advertised duration of 290° has a duration of 230° at 0.050" lift.

 
I believe the durations they gave you are at 0.050" lift, not advertised or total duration. For instance, Comp Cam's hydraulic roller retrofit that has an advertised duration of 290° has a duration of 230° at 0.050" lift.
::thumb:: Quick call to Comp Cams and you hit the nail on the head! Thanks for clearing that up. I swear, cams are like voodoo magic.

 
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