Cam advice

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Dec 10, 2017
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My Car
1973 Mach 1 "Q Code"
So it is about time for me to start building the engine for my 73 Mach 1, I ordered the Ford Cleveland book to do some reading but wanted to ask the question here as well.  Below is what my current set up is and what I plan to put in, below is a pic that I found on here a few weeks ago that another member was asking about.  I am wondering if these cam specs will be good for what I am planning with the car. 

1972 351C H-Code

8-inch rear end 2.75 or 3.00 ratio (no tag on pumpkin, did the rotate wheel process a couple months ago)  I have a line on a possible 9 inch from a 73 that I think is 3.25 - 3.50 gears and if I can snag that up, will change out the rear end

FMX transmission with stock TC ( I think, not really sure because I don't see any markings on it)

Dual exhaust, probably on stock manifolds (haven’t decided on headers yet, may have a set coming soon though)

Will probably be bored out to .30 over

Street/highway use, probably never hit the track

Would like a smooth idle and acceleration (will probably punch it off the line a few times but don't plan on always smoking the tires) 

Will be using the stock heads, but will be replacing the stock valves to the one-piece type as I have heard the original were two-piece

Flat top pistons

Carb will be 600-650 CFM (haven’t gotten to that point yet)

Stock crank, it looks good and shouldn’t need any machining (will verify with the machine shop though)

I do plan to use ARP nuts and bolts as well

The block will be going to the machine shop in the next week or so for cleaning, checking for any cracks, and if necessary boring out the cylinders

I believe at stock the H code was about 8.6:1 for compression. I would like to bring the compression ratio up and still have a balanced, good idle and performance. I will also be using pump gas, so I think I will have to have the hardened seats installed in the heads or use the lead fuel additive, is that correct?

Thanks for any and all assistance.


I ran that exact cam in what was essentially a freshened up 70 M-code 4V engine with headers and an 800CFM Holley DP. It had good street manners and would pull well from a fairly low RPM. Idle had a slight chop to it when cold that would smooth out a bit when fully warmed up. I ran it in several cars, from a 71 sportsroof with a 4 speed, to a 70 Torino GT sportsroof with a C-6 auto. It's a good cam, but it does have a built in rev-limiter, as it shuts off like a switch at 5600, and it's a well documented problem with that grind.

For your purposes, it should be just fine. It may not like the stock converter, but for how you describe it's use, it should be good.

Your plan sounds good, but I do offer a bit of advice. Have the block zero-decked, or as my builder is doing, .005" in the hole. Racetec makes a fantastic forged flattop piston. Have the whole assembly balanced and use a new damper, PowerBond is being recommended by many. ARP rod bolts are crucial, as is an ARP oil pump driveshaft. Consider an extra capacity oil pan. A top quality timing set is a must, such as those from Rollmaster, or at the least, Cloyes. This will give you a solid foundation if you decide to build more power later on, without having to worry about the shortblock.


To me the best way to choose a camshaft that will perform well on pump gas is to adjust your DYNAMIC compression ratio to achieve 

8.0 to 8.2 maximum.

you cannot pick a camshaft as of yet because you have no idea what your finished mechanical compression ratio will be.

72 degrees overlap is not going to yield you a very stable idle.

IMHO 62 degrees overlap would be a more suitable to good idle and low rpm performance.

get that mechanical compression ratio down pat and also gear ratio and tire size and you will get a lot more help from this site. 


This is the type of advice I am looking for, thank you all for your replies and the excel sheets. @hemi, until I look at the excel sheet Don posted, which converter would you recommend?