I read that the stock '69 250-6 cam makes a good power upgrade for a 200-6.
Has anyone done this and did the 200-6 make more power?
Has anyone done this and did the 200-6 make more power?
Stock 250-6 cam in a 200-6
- Thread starter mcknight77
- Start date
The stock cam specs are posted here..
Small Six Specs - 144/170/200/250ci -- FordSix Tech Section
If I'm reading it correctly, it looks like the specs are almost exactly the same, so I'd say that a stock cam swap wouldn't be worth the money if your original 200 cam is still in working order.
Small Six Specs - 144/170/200/250ci -- FordSix Tech Section
If I'm reading it correctly, it looks like the specs are almost exactly the same, so I'd say that a stock cam swap wouldn't be worth the money if your original 200 cam is still in working order.
Howdy McKnight:
The specs on a '65-.66 200 cam were 252/256 (i/e) duration with .348" of lift at the valves. The later 250 cam is rated at 256 duration with .368" lift at the valves. Later 200 cams were rated at 256 durations with .372" lift but are extremely advanced- not what you want for performance.
The 250 cam can be used in a 200- the notable physical difference is the scalloped shaft needed on a 250 to clear the rod throws. The small increases in duration and lift will likely not be noticeable in real application. The problem with stock OEM cams is the lazy profile- ideal for less wear and valve train stress, but severely lacking in performance when compared to a performance profile. While a stock cam and a performance cam will both be rated at 256 degrees of duration the performance cam will have a more aggressive profile and spend more degrees at maximum lift than an OEM cam. That and increased lift of about .400" lift will be noticeable for performance and still be as civilized as a stock cam. The cost of install will be identical, the variable being the cost of the cam.
What is your goal with this thought?
Hope that helps. Let us know.
Adios, David
The specs on a '65-.66 200 cam were 252/256 (i/e) duration with .348" of lift at the valves. The later 250 cam is rated at 256 duration with .368" lift at the valves. Later 200 cams were rated at 256 durations with .372" lift but are extremely advanced- not what you want for performance.
The 250 cam can be used in a 200- the notable physical difference is the scalloped shaft needed on a 250 to clear the rod throws. The small increases in duration and lift will likely not be noticeable in real application. The problem with stock OEM cams is the lazy profile- ideal for less wear and valve train stress, but severely lacking in performance when compared to a performance profile. While a stock cam and a performance cam will both be rated at 256 degrees of duration the performance cam will have a more aggressive profile and spend more degrees at maximum lift than an OEM cam. That and increased lift of about .400" lift will be noticeable for performance and still be as civilized as a stock cam. The cost of install will be identical, the variable being the cost of the cam.
What is your goal with this thought?
Hope that helps. Let us know.
Adios, David
CZLN6":3npkvsmn said:
I have a '65 Mustang Coupe. 5-speed. I drive it almost every day to work; round trip 52 miles, mostly interstate. I'm very happy with its performance as it is now. However, I'm having an E0 260-6 head modified for a 2v carb. Thought while I had the head was off to change the cam. It will not be a high performance oriented modification. I just want a bit more power because I will install A/C before summer. And, I want to get rid of the 1100 carb and LOM distributor. Compression will remain at the factory 8.7, 9.0 at the max. That dictates a cam with not more than about 210* duration.
What I don't want is a finicky weekend performance car. I have other cars for that.
Just thought the 250 factory cam would keep the mild manners the car has now, but give me the bump in power.
Howdy Back:
Ah, that helps. Yes, replacing the cam while the head is off is a great idea and good timing. You will have to do more disassembly to remove the radiator to get to the cam timing cover. Getting the lifters out through the top is a little bit of a hassle but doable.
Do you already have a set of adjustable rocker arms on the engine?
When you say, "a duration of 210" I'm assuming you are referring to the at .050" lift spec? If so, IIWIYS I'd be looming for a cam like the Comp 252H which has 206 duration @ .050" and lift of .425". Clifford and Schneider also have cams in this range. With a new performance cam you will have no need to upgrade to higher lift rocker arms. Any of these cams will give you a fairly broad power range. If you will add a back cut to the intake valves, that will further enhance low lift flow. As long as you are doing the 250 head back cutting is a no brainer. It will add only a few dollars to the head prep.
I would suggest that you replace the cam timing gears and chain and with a double roller type chain. With your use the double roller chain is less prone to stretch which in time will retard cam timing.
What is your elevation in western Idaho? If it is above 4,000 ft elevation you will do fine with a CR of 9:1 on regular gas. The heat of summer may require an occasional tank of 91 octane. The cam specs will bleed off some of the cylinder pressure making pre-ignition less likely.
I like the sound of your project. Keep us posted on your plan and your progress.
Adios, David
Ah, that helps. Yes, replacing the cam while the head is off is a great idea and good timing. You will have to do more disassembly to remove the radiator to get to the cam timing cover. Getting the lifters out through the top is a little bit of a hassle but doable.
Do you already have a set of adjustable rocker arms on the engine?
When you say, "a duration of 210" I'm assuming you are referring to the at .050" lift spec? If so, IIWIYS I'd be looming for a cam like the Comp 252H which has 206 duration @ .050" and lift of .425". Clifford and Schneider also have cams in this range. With a new performance cam you will have no need to upgrade to higher lift rocker arms. Any of these cams will give you a fairly broad power range. If you will add a back cut to the intake valves, that will further enhance low lift flow. As long as you are doing the 250 head back cutting is a no brainer. It will add only a few dollars to the head prep.
I would suggest that you replace the cam timing gears and chain and with a double roller type chain. With your use the double roller chain is less prone to stretch which in time will retard cam timing.
What is your elevation in western Idaho? If it is above 4,000 ft elevation you will do fine with a CR of 9:1 on regular gas. The heat of summer may require an occasional tank of 91 octane. The cam specs will bleed off some of the cylinder pressure making pre-ignition less likely.
I like the sound of your project. Keep us posted on your plan and your progress.
Adios, David
CZLN6":3iusqvfz said:
We're just 2800 ft. elevation over here in the banana belt so I'm going to mill the head for 8.7-1. It runs great now on 85 octane non-ethanol. Back cutting the intake valves, 1.5 exhaust valves, spring upgrade are in the plan along with roller chain and gears. I ran a 252H in my Chevy 292-6 for many years and was very happy with it. Those long duration cams and low compression don't do well together. Thanks for the help.
Jim
