Proper cam selection.

[harris4d]

I have acquired a 1978 200ci + C4 Transmission.
Over the next few months I plan on rebuilding the motor, So I'm collecting knowledge and parts prior.

I was thinking about Competition Cams 260/260 as it does get good reviews.
Then I read this viewtopic.php?f=1&t=73930
The subject of Howard's Cams 267/267 - 110 came up but I just can't find much published information on this cam.

So here I am asking for help.
My car 1962 Mercury Comet
It will be a daily driver - nothing radical but I do want as much practical power available.
I will be keeping the stock 1962 7.25" rear end.
Tires 75x60/15
Thinking I'll stick with the 1bbl carbarator.
And of course I'll be using the C4 Transmission.
Thank you, Darryl.

 

[CZLN6]

Howdy Darryl:

I see that you are not actually new, but fairly new so welcome anyway. I love your project. And as usual, I have more questions. What is your goal CR? Do you plan any modifications to the '78 head? On your one barrel carb choice, what carb? I'm guessing the '78 200 has a Carter YF? What exhaust are you planning for? Will you be using the '78 ignition?

But, my thinking is that if you were to maximize your CR, say 9.2 to 9.5, depending on your elevation and selected a cam in the 256 duration with about .400" lift and 110 lobe angle, you would optimize a lower torque and HP curve. That would be consistent with your stated goal as well as the auto transmission and the 3.25:1 rear ratio. This engine would still run out of air and top end, because of the one barrel carb limitations before the rest of the engine is ready to quit. In my mind, it doesn't make sense to kill the bottom end with too much cam given your carb limitations.

PS- you can up the cfm of the YF by finding and using a YF from a 300 pickup engine. 187 to 220 cfm.

That's my story and I'm sticking to it. Good luck and keep us posted.

Adios, David

 

[RichCreations]

As I said, as someone who was just in your shoes, call jerry at Schneider Racing Cams, They are very helpful (you talk to the head guy), and have some really nice grinds for our engines, he knows a hell of a lot more then any of us do about cam selection, and they have good prices (not to mention a nice product). he will ask a bunch of questions, things like gearing, car weight, type of driving, induction, etc. In my case the cam he suggested was "not in the catalog".

That said, their 256H cam might be about right (perhaps with a different LSA, which they will do for free)

(I do not work for, or am affiliated with Schneider, Just a satisfied customer.)

 

[harris4d]

Howdy Darryl:

I see that you are not actually new, but fairly new so welcome anyway. I love your project. And as usual, I have more questions. What is your goal CR? Do you plan any modifications to the '78 head? On your one barrel carb choice, what carb? I'm guessing the '78 200 has a Carter YF? What exhaust are you planning for? Will you be using the '78 ignition?

But, my thinking is that if you were to maximize your CR, say 9.2 to 9.5, depending on your elevation and selected a cam in the 256 duration with about .400" lift and 110 lobe angle, you would optimize a lower torque and HP curve. That would be consistent with your stated goal as well as the auto transmission and the 3.25:1 rear ratio. This engine would still run out of air and top end, because of the one barrel carb limitations before the rest of the engine is ready to quit. In my mind, it doesn't make sense to kill the bottom end with too much cam given your carb limitations.

PS- you can up the cfm of the YF by finding and using a YF from a 300 pickup engine. 187 to 220 cfm.

That's my story and I'm sticking to it. Good luck and keep us posted.

Adios, David

David, thank you for your response..
Yes I do have plans on going through the head and having some milling done. I haven't yet set a goal on the CR but your numbers sound in line.. 9.->9.5..

The current carbarator is a Holly 1946 but dang it has a bunch of trash attached. I would be open to a two barrel carburetor but I have the small intake head and not sure if the adapter would benefit stepping up to a two barrel.

On the exhaust system.. I might - repeat - might want to add air conditioning in the future and from what I understand headers and a/c don't work well together. So I'm thinking stock manifold stepped up to 2" exhaust.

Yes on the 78 ignition.

 

[harris4d]

As I said, as someone who was just in your shoes, call jerry at Schneider Racing Cams, They are very helpful (you talk to the head guy), and have some really nice grinds for our engines, he knows a heck of a lot more then any of us do about cam selection, and they have good prices (not to mention a nice product). he will ask a bunch of questions, things like gearing, car weight, type of driving, induction, etc. In my case the cam he suggested was "not in the catalog".

That said, their 256H cam might be about right (perhaps with a different LSA, which they will do for free)

(I do not work for, or am affiliated with Schneider, Just a satisfied customer.)

Thanks, I googled everything except that name.. Schneider Racing Cams..

 

[harris4d]

I'd like 2 C Darryl's typical driving conditions, elevation, use, RPM range etc (to offer assistance/get an understanding for me, others)
on it's own thread to reduce confusion, apply best practices, etc…

All I know is it's a "200 ci in a '62 comet", just can't imagine a 1998 engine,
sounds like he may need a block castings decoder.

Sorry, I didn't proof read prior to posting.. 1978 not 1998..
This would be a second car.. Recreational daily driver.
I live in Corpus Christi Texas and our four Seasons go pretty much as follows..
Fall.. Late Nov 20th through Dec.
Winter.. January through Feb 18th..
Spring.. Feb 19th through March 20th
Summer.. March 20 through Nov 20th..

Elevation <20 feet above sea level.

RPM range.. Unknown exactly at this time however I would probably be looking more power/torque at lower RPMs and less concerned with achieving 5,000 RPMs.

Thank you, Darryl.

 

[chad]

Thanks for the post.
Sometimes 'cross posts' get a lill confusing, U don't get YOUR full due either.
I deffer to David & RichC as the bronk (current project) is my 1st build (more interest here in tq than HP, too).

Most the guys recommend the DSII system (it came in @ '77 I believe) and when on the rd & done, a recurve to the distrib.
(So U have the lrg log head & possibly DSII).
As David posted - U may want to rework it (head) while the motor is being done/cam change.

 

[CZLN6]

Howdy Back Darryl and all:

A '78 head will have a 1.75" carb opening and the best of FOMoCo intake valves. The adapter and two barrel is still an improvement over a one barrel but it raises other issues such as hood clearance, linkage and plumbing.

A well plumbed 2" exhaust with a Turbo type muffler is a nice upgrade.

If you are staying one barrel, consider a Carter YF. It was the stock carb in '78 on 200s with a manual trans.

Just some thoughts.

Adios, David