i gotta 73 f100 4x4 with a 390,4 speed,4.11 gears,stock motor and i was looking at a bigger cam its the comp cam cl33-224-3, duration at 050 is 218 intake and 218 exhaust. advertised duration is 268 intake and 268 exhaust. valve lift is valve lift is .494 intake and .494 exhaust. the lobe seperation is 110 degrees

 

Any idea of what the static compression is to start with? The wrong lobe separation can drop your ratio lower than you expect.

Chris

 

i have no idea what the compression is

 

Maybe you can find some info from the cast numbers. I am not an FE guy, But start with the heads, Find out what the CC options were, Most motors, and again i know nothing of 390's) have the same pistons and the heads were changed for different compression ratios.
start plugging in some number and see what you get.

Ford "FE" engine specifications

http://www.summitracing.com/expertad...ion-calculator

here is something from a AMC 360 i built

 

If the only thing you change is the cam, you will most likely not be pleased with the outcome.

The cam itself is reasonable for a mild motor, but should have a better intake and exhaust system than stock, and be sure to install new valve springs designed for the cam.

At a minimum, I would start with a true dual exhaust system, with a cross over pipe. Headers are always a good improvement over stock FE manifolds. Follow the exhaust with a decent 4 barrel intake and a carb no larger than 600 cfm. With the intake off is the time to install the cam and kit. I would also look at replacing the timing chain and gears since you will have them off for the cam swap.
If you still have a little left in the budget and ignition upgrade is always a good idea. Most any electronic conversion that does away with point should be fine for the above combination.

You asked for opinions and these are mine. My opinions are based on over 45 years working on FE engines.

A couple things to remember.

A good running engine is a combination of all it's parts. Throw an odd or mismatched part in the mix and it is a pretty safe bet you won't be pleased with the outcome.
When dealing with a stock or near stock engine less is usually more. By this I mean if choosing between items, go for the smaller. That is, the cam with less duration, the carb with less cfm, the intake with the lower rpm range.

You will hear a lot of differing opinions and probably many that disagree with my opinions. That's OK.
I will say I have never had a customer dissatisfied with the performance of their FE when I followed my own advice.

Hope you find this helpful.
Good luck.

Roger Carter

 

i am getting headers and i plan on doing intake and carb. would that camshaft work?

 

No question it would work. Different question, is it best and will make you happy? If you are running a stock or stock style rebuilt engine with low compression + intake and exhaust improvements I believe 1 size smaller (~262 intake duration) would work better. More torque and performance at common operating RPM and a touch better fuel economy. Take this as what it is worth. I'm by no means an FE expert.

 

i think either the 268h or 270h would be good cams if you have a high compression 390 over 9.5 to 1, 4 barrel carb and hedders when i bought my hiboy with a 390 the owner couldnt remember which cam he put in it but knew it was a 268h or 270h well i found the cam card in the glove box like a year after i bought it and it was a 270h but if your 390 is stock i hear the 252h or 260h are better cam choices

 

Are you even open to the suggestion of a custom cam? They are not just for race motors, they will out perform an OTS cam in all aspects when set up properly. Better idle, better drivability, more power and better fuel economy. JMO.

 

I don't think I would get a custom cam. How do I know if I have high or low compressoin?

 

Here you go,,, took one google search, not sure if it is you motor. It came from this website.
https://www.ford-trucks.com/forums/1...cs-needed.html

compression 8.6 to 1
bore 4.05
stroke 3.78
bore spacing 4.63
crank nodular iron
journal diameters main 2.749
rod 2.438
deck height 10.17
deck height clearence .010
connecting rod length 6.49
intake valve 2.04
exhaust 1.55- 1.56
stem diameter .371
hydraulic lifters
1.73 rockerarm ratio
shaft non adj
not externally balanced

none the less,, if your motor is tired, it is putting out less compression and too much duration will make it even less. But in short,,, Yes the cam will work/run. It might not yield the results you think after the time and money.

When i was a kid, I ran a 400 pontiac, very small cam, no stall conv, 354 gears, buick turbo 350. I had a little bit of head work done and the 3800 lb car would run 13.50 all day long with street tires. I ran against so many guy with big gears, big cams, and all they did was make noise.

 

A '73 4x4 did not come with a 390 from the factory.

If the engine in the OP's post is in fact a 390 it is anyone's guess what the compression is. Originally it could be anywhere from the low 8" to mid 10's to 1. 40 years of modifications could have cheange it as well.
If the engine is a 360, that could have been available from the factory, the compression is in the 8.0-8.5 to 1 range, barring any changes or modifications.

As others have said, compression will have a direct bearing on how your engine reacts to any cam. As I said in my previous post, when faced with a choice on a basically stock engine, go smaller. I believe the cam you have chosen would work in conjunction with the other pieces I listed. I know that you would be pleased with a 260 type cam.

Montana4x4xford, shy of confirming the dimensions needed to work the spreadsheet provided by Chris989 there is no way to accurately determine the compression of the engine in your truck. There are methods to give a best guess, but even then it is still a best guess.


RC

 

You need to figure out the C/R before anyone can give you a definitive answer/recommendation.

Is this an early 390/late 390? truck 390/car 390? any additional info would at least give us some ballpark specs to work with.

A low compression/stock 390 would best be suited with a 260H, if it's a higher compression/mildly built 390 a 268H or 270H would be a better cam selection.