Camshaft selection for a 200

[Fairmont200]

Hello, I have a 78 fairmont with a 200 , automatic . 56k miles I am looking to do a cam and headers, which cam is a good choice for a automatic ? I would like to hear a lopey idle . Any direct bolt in with no piston to valve issues of course , any suggestions would be great

 

[jahearne]

Welcome!

http://www.classicinlines.com/SelectCam.asp

is the best place to start. Many have had good luck with the dual pattern cams. Our inlines are non interference motors, so you won't hit the piston; however, you may want to keep an eye out for coil bind on the springs.

 

[falcon fanatic]

Hi there,
I have the 264/274-12* cam and I have to say it is not ideal for a car with an automatic and a stock torque converter as the idle vacuum is kind of low. Were I to select a cam for a mild performance engine build again I'd probably go with a 264/264-10*.

just my $.02.

Cheer,
James

 

[rocklord]

Be careful about overcamming an engine with an automatic. My brother wanted a lopey idle, and wound up overcamming his 302 Mustang with 3.55 gears; had to go with a high stall converter to make it drivable. Finally switched to a 4spd.

Talk with Mike and see what he says. Also listen to the guys here who've been there, done that.

Good luck.

 

[CZLN6]

Howdy Fairmont:

And welcome to The Forum!!! Yes, it is that good.

Upgrading the cam on a '78 200 is a real good idea, considering the low end and emissions bias of the stock cam. But, know that a longer duration performance cam will lesson cylinder pressure and that a '78 200 is already down on compression ratio. Add to that the typical high rear end gear of that generation fairmont and low end grunt will be disappointing. So long as you almost certainly have to remove the head to install the cam, I suggest that you plan to raise the CR, by milling the head. Getting the CR up to, at least 9:1 will be a plus on several fronts. While the head is off you could take advantage of several other upgrades- a three angle performance valve job, back-cutting the intake valves and installing the port divider that will come with the header (I think).

If your lucky enough to have a Carter YF carb rather than the later Holley #1946 you will have several options to bolt on a larger capacity one barrel carb also. Either an RBS from a 250 or a YF from a 300 ci six will increase cfm from 185 to 210 range. Other than the header, you will have a very nice, stock appearing engine package with a lot more punch.

And, finally, getting a rear end ratio in the 3.25:1 will also be a big help.

Piston to valve clearance will not be an issue. What is your location? Elevation?

Again, welcome and keep us posted on your progress.

Adios, David

 

[rocklord]

If he has to take the head off, why not do a 2Bbl direct mount instead of keeping with a 1Bbl?

Other than that, I agree with everything else Dave said.

 

[MPGmustang]

Howdy and Welcome relax you found the best place to be.

I've done some exstensive research in this area, If I were to do it again, I'd go for a torque motor, it's what gets you off the line.

I've been looking at 256/256 .480 with 108* the .480 lift is only be with 1.6 rocker ratio, this is the best of both worlds (on paper)

256 is not aggressive towards HP, but torque, the higher lift will help overall the spectrum, and the 108* helps in HP, then go for a 9.5 CR and you have a mean little six that is decent off the line and a great low rpm torque cruise monster.

if you want little more HP, then by far the 264/264 108* .450 (with 1.5 rocker ratio) is a GREAT cam. but IIRC any cam with 108* won't cut it for you on vacuum. maybe goting for a 112* (112 lowers HP but rasies tq and vacuum) aim for a 9.5 CR

Good Luck
Richard

 

[Fairmont200]

Thanks for so many quick responses, I will be looking into doing springs and a mill as I have a machine shop that we work with at our shop. This is the first inline that I have done , any sound files for the cams? As I said of course performance is first but I would like to hear the cam also (lopey) . I am not concerned with vacuum as i have manual brakes, but I do have a automatic . Figuring tthe differences of the stock head gasket to aftermarket .25. I was going to have the head milled for the correction , but to raise the compression to 9.1 how much more should be milled?

 

[CZLN6]

Howdy Back:

Q- Figuring tthe differences of the stock head gasket to aftermarket .25.

A- Make that .025" and I'll agree. Darn those pesky decimals. Stock OEM steel shim is .025" compressed. Aftermarkets composites range from .045" for Victor to .055 for Fel Pro. Both seal a bunch better than the OEM.

Q- I was going to have the head milled for the correction, but to raise the compression to 9.1 how much more should be milled?

A- Approximately .050". Roughly .010" for every 2 ccs less. The goal will be to measure the chamber volumes at or close to 50 -52 ccs to be close to 9:1 Static or mechanical compression ratio. Remember, a performance cam will help to lessen cylinder pressure and lessen the likely hood of pre-ignition. So will polishing the combustion chambers.

Keep it coming.

Adois, David

 

[Fairmont200]

Ok so initially the head should be milled.025 and then cc'd . after the cc is recorded then it should be milled .010 for every 2 ccs until we reach 52ccs. Sorry if i am being redundant but I just want to make sure I understand. And as far as the camshaft I was thinking something like a clay smith 274 with a 110 lobe separation. Any manufactures that you would recommend? It seems from what I have been reading that camshaft will also give me the exhaust lope that I will be looking for also.

 

[rbohm]

8) teh very first thing you want to do when choosing a cam is to decide on what you want from the car, i mean really want not just what sounds good, and what rpm range the engine will spend 80% of its time in. for instance, if you are building a better daily driver, then you want the engine to perform in the 1000-4500 rpm range, and since you have the automatic, you also want a smooth idle and good off the line torque. as a daily driver this car MUST be dependable, especially if your significant other will drive the car.

i can tell you from experience that the stock 200 in the fairmont does quite well as a daily driver, and really only needs about 15-20 more hp to be really good. to that end consider a set of high ratio rocker arms before a cam swap. that will give you more lift with out a big increase in duration and its attendant issues. do make sure that you dont run into coil bind though.

if after dropping on the high ratio rockers, you still feel you dont have enough cam, then step up to one of the smaller cams available from classicinlines with a lobe separation angle of 110-112 degrees. the nice thing is you can keep the high ratio rockers as well. at the same time bump the compression up to 9:1 or so.

i also agree with getting rid of the salt flats gearing and stepping up to a 3.27 rear gear, or at least a 3.08. these will be MUCH better than the stock 2.49 gears.

 

[Fairmont200]

I use the car 3-7 miles a day , sometimes go for a 15 mile cruise, so I'm not too concerned about fuel mileage or being able to go on long trips with it, as for my wife,lol she won't be caught dead in it lol so I don't have to worry about her driving it . We have two other new cars and one supercharged mustang so this is just another toy for me. I was really looking to do something different instead of putting a sbf in it .

 

[CZLN6]

Howdy back Fairmont and All:

I'd recommend selecting you head gasket replacement choice and then plan to have the head milled to match the numbers. Say .050" and another for which every gasket set you choose. With a Victor set that would be a cut of .070". Then cc the chambers. That will get you close, maybe close enough. You didn't give your location. What is the elevation where you live?

Rbohm is giving good advice on the big picture in selecting the cam. IF this is your commuter you'll want a clean runner with good low to mid range power. Your tune and your exhaust will also effect the idle quality and sound.

Check and post your rear end gear ratio.

I would, respectfully, disagree with rbohm on 1.6:1 rocker arms in your case because the 3.3/200 engines got a different cam degreeing bias as compared to earlier OEM cams. Increasing lift would help, but would not solve the cam bias problem. FoMoCo advanced the profile design on these cams to emphasize low end, low emissions and mileage. With the stock gearing and mileage bias is works fairly well, but for any performance above about 3,500 rpms it lacks.

My concerns would be to match the cam to the trans and rear end gear ratio combo, first and then to my typical driving patterns. If you do over cam, you can compensate with a looser torque converter and lower rear end gearing. By the way, what rear gear is in the car? What carb do you have? What carb are you planning for when you're done?

Keep it coming.

Adios, David

 

[JackFish]

Nobody has mentioned getting a double-roller timing chain from Mike and advancing the timing.
So I will!
I did that to what was then a stock motor, and I think it's the best bang for the buck.

 

[rbohm]

I would, respectfully, disagree with rbohm on 1.6:1 rocker arms in your case because the 3.3/200 engines got a different cam degreeing bias as compared to earlier OEM cams. Increasing lift would help, but would not solve the cam bias problem. FoMoCo advanced the profile design on these cams to emphasize low end, low emissions and mileage. With the stock gearing and mileage bias is works fairly well, but for any performance above about 3,500 rpms it lacks.

Adios, David

8) when dealing with factory parts, it isnt so much a cam bias as a port bias. most factory cams are single pattern cams, which generally is less expensive to make than a dual pattern cam. the problem is that with single pattern cams you are ignoring the generally large difference in port flow from the intake to the exhaust. one way to combat this is to use more rocker arm ratio on the exhaust side than the intake side.

 

[Explorer]

Howdy and Welcome relax you found the best place to be.

I've done some exstensive research in this area, If I were to do it again, I'd go for a torque motor, it's what gets you off the line.

I've been looking at 256/256 .480 with 108* the .480 lift is only be with 1.6 rocker ratio, this is the best of both worlds (on paper)

256 is not aggressive towards HP, but torque, the higher lift will help overall the spectrum, and the 108* helps in HP, then go for a 9.5 CR and you have a mean little six that is decent off the line and a great low rpm torque cruise monster.

if you want little more HP, then by far the 264/264 108* .450 (with 1.5 rocker ratio) is a GREAT cam. but IIRC any cam with 108* won't cut it for you on vacuum. maybe goting for a 112* (112 lowers HP but rasies tq and vacuum) aim for a 9.5 CR

Good Luck
Richard

I'm running the Isky 256/256 .488 112 lobe and 9.7:1 comp. It has worked out really well for me. But if you want the lopey idle, thats your decision.