FE Block, Comp Cam 270 Magnum, Issues

[moose425 16]

Does anyone have experience running a comp cams 270 magnum cam in an FE block (mine is 390)?  Where there any vacuum issues with carb, brake booster, etc?  Did it have excessive lope at idle?  My engine basically stock except for holley 650, edlebrock heads, headers.  Toploader 4 speed.  Thanks for any help!!

[barnett468 418]

I would not use that cam unless you port the bejesus out of the exhaust port . People use those single pattern cams because they read on the internet or something that they were great . It will have a mild lope.

[moose425 16]

Is there a cam you would recommend?  What about a comp cams XE262?  Right now, I am basically running a stock cam.  Thanks.

[barnett468 418]

it would help to have a lot more info like gear ratio, compression, exhaust, intake, vehicle type and your goal but an xe262h is a good stock type replacement . it will have good bottom and lower mid range power and good throttle response and will fall on its face around 4500 rpm.

[moose425 16]

I have a toploader with a wide ratio gear set, my rear end is 3.25 to 1, compression is stock 9.5 to 1, exhaust and intake are Edlebrock aluminum heads,  hooker headers, flowmaster pipes, holley 650 carb, car is a 1969 Mustang GT.  I hardly ever tach this car above 4000 rpm.  Would like a little better throttle response in the lower end and some lope in the exhaust at idle.  Presently I don't have any lope.  Will the XE262H satisfy my needs?  Thanks for your help!!

[Rsmach1 71]

Keep in mind, the more lope there is, the less low end performance, not to mention lower vacuum for power brakes. I'd look at something like this http://www.lunatipower.com/Product.aspx?id=1673&gid=287

 

Or this max http://www.lunatipower.com/Product.aspx?id=1674&gid=287

But this one will effect power brakes to some extent.

[barnett468 418]

oh man, you are killin me . that thing needs a fairly big cam and 3.43 gears.

 

its a tough call what would be best for your particular app . the most important thing is power so in your case, a comp or lunati 256 cam might be best.

 

you have eddy rpm heads?

 

what intake?

[Rsmach1 71]

One more question, are you using adjustable or non adjustable valvetrain?

[barnett468 418]

.

oops, two more questions . what is your rocker ratio?

[moose425 16]

my rockers are adjustable, and the ratio is stock which I think is 1.69 to 1.  Also, if I go with a cam that has more lift than stock, do I need to be concerned about the additional strain on my valve train and spring fatigue?  Thanks to all. 

[Rsmach1 71]

If stock it will be 1.73, Ford adjustable 1.76.

[moose425 16]

You are correct, I just checked my book.  My rockers are adjustable with a ration of 1.76 to 1.  Thanks.

[Rsmach1 71]

If you change to a bigger cam you might need new springs. Are you running Ford original or aftermarket rockers. If so whos?

[barnett468 418]

my rockers are adjustable, and the ratio is stock which I think is 1.69 to 1.  Also, if I go with a cam that has more lift than stock, do I need to be concerned about the additional strain on my valve train and spring fatigue?  Thanks to all.

you can run up to .600 lift on the eddy rpm heads with a non roller cam.

[Rsmach1 71]

So what is the car used for, cruising, weekend warrior, any trips to the strip?

[albarnett_99 13]

You might want to post your question on the Network 54 Ford FE Forum and pick up Barry Robotnik's book on FEs. The FE Forum has a bunch of extremely knowledgeable FE gurus who regularly share advice and dyno results from various builds from low budget stock to high dollar racing stuff.

 

Or consider reaching out to Jay Bown, Barry Robotnik, or Brett Lykins for advice. These guys have built many different FE combinations and always share their knowledge.

[SM69Mach 68]

I ran the 270H cam in my stock 390 for a few thousand miles with no issues.  It was slightly bigger than stock, had a good idle to it, but not too aggressive.  I had plenty of vacuum for power brakes.  I wouldn't say it was a power house by any means, but it did wake the car up some.  There are definitely better cams, especially since you are running Alum heads already.  I would definitely look on the FE forums for more info.  I have seen the 282S (solid cam) recommend quite a bit but I did not want a solid cam in my street only car. 

 

My suggestion would be to convert to a roller cam if at all possible.  I had a 280H cam tear itself up recently and had to the pull the motor out and apart and just made the conversion.  All of the guys listed above will give you good recommendation on what to use.   

 

Also, what shafts and rocker stands do you have?  Are they upgraded or stock?  Depending on what cam you go with, you might want look at the upgraded shafts and/or stands from Precision Oil Pumps.  http://stores.precisionoilpumps.com/

[Max Power 74]

I ran a 280h cam years ago in the 390 in my Eliminator with stock GT heads and it worked pretty nice, from memory.

[barnett468 418]

I hardly ever tach this car above 4000 rpm.  Would like a little better throttle response in the lower end and some lope in the exhaust at idle.  Presently I don't have any lope.  Will the XE262H satisfy my needs?  Thanks for your help!!

I have built countless FE engines, and although some of the guys mentioned are definitely extremely knowledgeable, your goal is so incredibly modest that going to them for help would be like consulting NASA to find out what the best rubber band would be to use on your balsa wood airplane . There are also enough people on this site that have experience with FE's that you will get the info you need, although much of it has already been posted.

 

As far as a single pattern cam goes, it will work better with the Eddy heads than it will with the stock ones . I didn't know you had Eddy's when I made my orig post.

 

The Comp 256 cam will have slightly more lope than the Lunati 256 cam, however, neither cam will produce a very noticeable lope.

 

If you aren't on a stringent budget, you could have a custom cam made . If you do that, I would have Chris Straub make it . A flat tappet hydraulic one is $275.00.

 

http://www.straubtechnologies.com/

 

 

My rockers are adjustable with a ration of 1.76 to 1. Thanks.

With that ratio, you will have slightly more lift than the cam mfg's state and the valves will open slightly faster than they would with the lower ratio rockers, both of these things are good in your particular case.

 

It would also help to know exactly what cam you currently have.

.

[moose425 16]

I'm not sure what cam is in my car now; but it idles as though it is stock.  My intake is Edlebrock Aluminum.  The tech guys at comp cams are really recommending an xe262 cam.  I found the following video which is an engine similar to mine with the XE262 cam. http://camshaftsounds.com/cam-video/390-fe-comp-xe262h-218224-050-110lsa-75-f-100/ 

 

The xe262 cam is supposed to hold a good vacuum, and the lope in the video exhaust is what I am after.  From what I can gather, overlap (both intake and exhaust valves open at the same time) produces the lope in the exhaust.  The xe262 cam has 1° of overlap, and it seems to be what I am after. Does anyone have any experience with the comp xe262 cam in an FE block?  Any known issues?  To keep from having to read my inputs above, I have a 1969 Mustang GT, 390 CI FE block, toploader wide ratio four speed, 3:25 to 1 rear end, holley 650 dp carb, edlebrock aluminum intake and heads, 1.76 to 1 adjustable stock rockers on stock shafts (springs came with Edlebrock heads), stock 9.5 to 1 pistons, engine has been balanced and blueprinted, 0 decked.  No boring or stroking.  Thanks for all the help from everyone.  

 

 

[barnett468 418]

nice car, cute house.

 

The xe262 has way more than 1 degree of overlap if you use the advertised duration numbers . i have used that cam in 390 fe engines before and it is he first cam i suggested based on your criteria but the xe256h will fit your rpm range better . you will give up a little low end power with the xe262h . if you have a custom cam made, you will get closer overall to what you want because you have a request that can not be filled by an off the shelf cam.

 

Also, if you bought your engine or car with those parts on it, i would be incredibly surprised if the installed a stock type cam . that would simply defy every bit of engine building logic.

 

The point is, you may get a cam that performs less to your satisfaction because we don't know what you currently have.

 

.

[moose425 16]

The guy I bought the car from years ago told me he went "down cam" to basically stock because he did not like the lope in the exhaust that was in the car when he bought it.  I can only assume it is close to stock right now. He did not give me any paperwork on the cam replacement he did.    

[barnett468 418]

The guy I bought the car from years ago told me he went "down cam" to basically stock because he did not like the lope in the exhaust that was in the car when he bought it.  I can only assume it is close to stock right now. He did not give me any paperwork on the cam replacement he did.

Well, it only takes a couple days to get a cam, and it is possible that we or the cam mfg can identify your current cam by the numbers on it, therefore, one option is to tear it down and determine what it is before you order a cam . This being said, my guess" is that it won't change the cam suggestions by much if at all due to your particular requests.

 

One thing that hasn't been mentioned is lifters . I would run Crane anti pump lifters or Crower cam oiler lifters.

[moose425 16]

I think I will do as you suggest, wait until I get the current cam out before buying a replacement.  Thanks for mentioning lifters, I was just planning on buying a cam and lifter set (from Comp, etc).  Are the comp cams lifters problematic?  Should I avoid them if I go with a comp cam.  Thanks again for all your help.    

[SM69Mach 68]

Go roller if you can.  Will have to measure for new pushrods, but none of the worry that comes along with the hydraulic flat tappets.