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post #1 of 26 (permalink) Old 02-15-2017, 05:56 PM Thread Starter
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Cam indecision

I have read a billion different “help me pick a cam” posts on a million different forums, and yet I find myself posting yet another “help me pick a cam” post of my own. Please bear with me—here we go.

I am in the process of building a 331 stroker. The shortblock is being assembled by an engine builder (who may also do the cam installation). Here are (some of) the relevant details for cam selection:
Car: 1965 Convertible
Block: 1965 289 (non-roller)
Heads: AFR 185
Intake: Edelbrock Performer RPM (non-Air Gap) & Summit 600 CFM carb
Trans: T-5
Rear: 3.55:1
Tire: 225/60/15 (i.e., limited traction)
Use: Cruising, weekend fun car, “Street performance.” No track or strip. Max fun over max power.
Here are the cams under consideration. They are all Comp Cams, but not for any particular reason. Only because they are plentiful and easy to compare to one another. I’ll gladly consider something else (Lunati, Anderson, Crane, etc., even custom), but I’ve got to narrow my choices at some point.

1. My initial choice based on a ton of Internet reading:
Hydraulic Roller (w/link bar lifters)
XE266HR (35-514-8)
Duration @ 0.050: 216/224
Valve Lift: 0.544/0.555
LSA: 112⁰
RPM Range: 1600 - 5600

Cam: $280
Lifters: $400
Total: $680
The link bar roller setup is expensive, but I’m willing to do it if it is significantly better than the alternatives. Folks seem to like this grind and the next step up, XE274HR.
2. My engine builder’s recommendation:
Hydraulic Flat Tappet
XE262H (31-238-3)
Duration @ 0.050: 218/224
Valve Lift: 0.493/0.5
LSA: 110⁰
RPM Range: 1300 - 5600

Cam & LIfters: $210
Valve Springs: $70
Total: $280
In not so many words, the builder thinks the roller cam/link bar setup is unnecessary and too expensive when considering my application. After all, it is a street car, and it will be traction-limited anyway, so I won’t benefit (much) from the extra HP and RPM of the roller. He has had good luck (happy customers) with the XE262H in similar builds in the past. This cam will require me to replace the valve springs with a lighter version, but it will still be way less expensive than a roller setup. Nearly as much bang for much less buck?
3. 2nd Choice of engine builder (if I insist on roller)
Hydraulic Roller (reduced base circle)
281HR (31-432-8)
Duration @ 0.050: 220/220
Valve Lift: 0.512/0.512
LSA: 110⁰
RPM Range: 2000 - 5500

Cam & LIfters: $472
Dog bone & Spider: $48
Total: $520

I have read a lot of mixed opinions regarding reduced base circle cams. The engine builder acknowledges that they are not as good as a regular roller with link bar lifters, but, again, more than adequate for my application. The benefits of a roller at considerably lower cost.
4. Comp Cams recommendation:
Hydraulic Roller (reduced base circle)
XR276RF-HR (35-424-8)
Duration @ 0.050: 224/230
Valve Lift: 0.513/0.513
LSA: 110⁰
RPM Range: 1800 - 5800

Cam & LIfters: $472
Dog bone & Spider: $48
Total: $520
I filled out the fairly extensive online form at Comp Cams website, and they sent back a brief email about a day later recommending the cam above. They didn’t provide much in the way of an explanation to go along with the recommendation.
So, here are the questions:

1. How would you rank the four cams listed above considering both overall cost and suitability for the stated application?
2. Is there another off the shelf cam (any brand) that seems particularly well suited to my application?
3. What would you consider the ideal cam specs (duration, lift, lsa, etc.) for what I am trying to accomplish?
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post #2 of 26 (permalink) Old 02-15-2017, 06:21 PM
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I am building the exact same engine for the exact same car right now and have been pondering the same question for the last year. The only difference in my set up is that I picked up a roller 5.0 block instead of using the 289. After a ton of research and talking to a bunch of people, I have decided on the 266HR. It still has a decent idle that should pull enough vacuum for power brakes and with the AFRs should make excellent midrange power and pull to about 5800rpm or so, which is as high as I'll ever spin it on the street in my vert.

You will find a number of happy 266HR users on VMF.
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post #3 of 26 (permalink) Old 02-15-2017, 07:01 PM
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I am basically at a similar spot and thinking I am going to use an Explorer 5.0 as a starting point. Aside from that, Ill add something to cloud the water...

In regards to roller v flat tappet: A roller has less parasitic drag compared to flat tappet, I know that this doesn't pan out to much HP on a dyno and it can't compare directly due to different profiles, but... How much of the reduced parasitic drag translates to cruising fuel economy? Before I get bashed for "why consider a stroker/muscle car/ fill in the blank for economy" it is part of the modify for improvement reasoning even if it doesn't make perfect dollars and sense. I mean, can a 331 roller eek out another 2mpg cruising over a similarly spec'ed non-roller? or 10 years from now when we are paying EURO type pricing for "petrol" will we kick ourselves for not spending up the extra $$. Shoulda, coulda, woulda.

Chris W
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post #4 of 26 (permalink) Old 02-15-2017, 07:08 PM
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A short while back I was looking at cams. I have a GT40P in my 66. I was looking to swap out the stock Explorer cam for something a little more aggressive. I was going to put a E303 cam in that was given to me but somehow got wet, rusted pretty badly. There are other cam companies out there besides Comp Cams. I never even looked at them. I spoke with Howards Cams. There you actually talk to someone who's listening and talking with you and not reading off a scripted flow chart. I would highly recommend talking to a tech for a cam, even if you call Comp Cams. I wouldn't be surprised they recommend a tighter LSA such as 110* This will give you a stronger low to mid range torque where you need it. I've seen a couple custom ground specs. They tend to have a lot of lift, like .570"+ lift and around 220* duration. Even if your heads stop flowing at .500" that extra lift means the valves will be open at that .500" range longer and fill the cylinders better while keeping the duration mild.

I've read a fair amount on flat tappet vs roller in the past more out of curiosity then anything else. I've read that unless you go over about 280* advertised duration, a flat tappet has the advantage. A flat tappet they say is acceleration unlimited but velocity limited and a roller is velocity unlimited but acceleration limited.

They say you're better off with a milder cam then you thought. Maybe that's true. I ended up with a used Mustang 5.0 cam, It idles smoothly and has a lot of torque right where I drive. Very happy with it. if you go with flat tappet, there is a lot more oil being sold today with the zinc levels you need then a few years ago.
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post #5 of 26 (permalink) Old 02-15-2017, 07:23 PM
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I will give you real numbers and not some fluff. Both of these are 347's, 10.25:1 compression, #1 has a 216 duration hyd roller, about the same lift and GT40 tubular intake and was a torque monster at 470torque with great idle qualities. The 218 was another 347 with just 2 more degrees and a Holley systemax intake, the 218 duration cam is not done being tuned yet, should have a video later tonight. Point is your 331 will make a little less torque but you can see that you will be happy with both. Don't think about it too much but I would go standard base circle and the link bar lifters if I were you.
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File Type: jpg 218.jpg (88.9 KB, 29 views)
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post #6 of 26 (permalink) Old 02-15-2017, 07:29 PM
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There is no way I would remove the valve springs that come stock on the new AFR renegade heads so I could run a flat tappet cam. You are better off using the link bar lifters and run a hydraulic roller cam. For OTS cams my choice is Anderson. The B-31 may be a good choice for you even though it is listed as a blower cam it will work great naturally aspirated with a carb. I run the b-41 in my driver with my budget 331 N/A that dynoed 435HP and 415TQ Idles well with great runability and rips high 11's in the 1/4mile. This would be my choice on link bar lifters
Morel Hydraulic Roller Link Bar Lifters

Last edited by cmefly; 02-15-2017 at 07:39 PM.
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post #7 of 26 (permalink) Old 02-15-2017, 07:36 PM
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I'm always a bit baffled by the people that build these rather stout engines. They all have the same disclaimer "Use: Cruising, weekend fun car, “Street performance.” No track or strip. Max fun over max power."
I have but a mere 289 with a Edelbrock performer plus clone cam T-5 3.40 TL.I Daily it mid April to Mid October And hit a couple autox's And opening weekend at Watkins.
My engine is all you need for your intended use.I on the other hand could use a few more RPM
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post #8 of 26 (permalink) Old 02-15-2017, 07:45 PM
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If you don't want to change the valve springs to be compatible with a flat tappet cam, in which case my choice would be the engine builders first pick of the XE262H or even an XE256H, then my pick would be link-bar lifters and a '90-93 5.0HO cam with 1.7:1 rockers on the exhaust side.

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post #9 of 26 (permalink) Old 02-15-2017, 07:48 PM
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Quote:
Originally Posted by Tobias_Aldrete View Post
I will give you real numbers and not some fluff. Both of these are 347's, 10.25:1 compression, #1 has a 216 duration hyd roller, about the same lift and GT40 tubular intake and was a torque monster at 470torque with great idle qualities. The 218 was another 347 with just 2 more degrees and a Holley systemax intake, the 218 duration cam is not done being tuned yet, should have a video later tonight. Point is your 331 will make a little less torque but you can see that you will be happy with both. Don't think about it too much but I would go standard base circle and the link bar lifters if I were you.

Can you post some more details on engine #1? The torque figures on that are ridiculously good.
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post #10 of 26 (permalink) Old 02-15-2017, 09:00 PM
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Quote:
Originally Posted by Woodchuck View Post
If you don't want to change the valve springs to be compatible with a flat tappet cam, in which case my choice would be the engine builders first pick of the XE262H or even an XE256H, then my pick would be link-bar lifters and a '90-93 5.0HO cam with 1.7:1 rockers on the exhaust side.
I just wanted to add a little note to Bart's comment on the stock HO cam. The specs for the 85 to mid 89 are .444" lift on both I&E, 210* on both I&E with 115* LSA. The mid 89 to 95 HO cam is the same except the intake has 10* more duration at 220* while the exhaust still has 210*. In my P motor I'm running the later 5.0 with 1.72 Crane roller rockers. It's a very good combination. Not saying it runs better if the intake had the standard 1.6, I haven't tried but as is, runs very well! It could very well run better if I swapped to 1.6 on the intake with the 1.7 on the exhaust.

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post #11 of 26 (permalink) Old 02-15-2017, 09:28 PM
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Quote:
Originally Posted by Woodchuck View Post
If you don't want to change the valve springs to be compatible with a flat tappet cam, in which case my choice would be the engine builders first pick of the XE262H or even an XE256H, then my pick would be link-bar lifters and a '90-93 5.0HO cam with 1.7:1 rockers on the exhaust side.
My $0.02 would be to recommend the XE262H for a great budget build that has a good sound, plenty of torque, and extremely streetable. I have one in a 351W, and am very happy with it. The only thing I would add is that even though they give a higher RPM range, in my car it seems to stop making power around 4800-5000, which matches dyno sheets I have seen on it with similar builds. I would also think you can keep the valve springs that come with your heads, but I would call comp cams to verify.
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post #12 of 26 (permalink) Old 02-15-2017, 09:41 PM
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I have been researching doing a stroker build myself and came across this article about flat tappet vs roller cams...one of the better ones I have seen. Thought I would share since you sound like you are trying to decide between the two. It would be awesome to see a dyno sheet with the same build comparing a roller cam to a flat tappet...there is probably one out there somewhere...

Are roller cams better than flat tappet cams?

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post #13 of 26 (permalink) Old 02-15-2017, 10:26 PM
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OP, any of those four cams will work just fine for your application. you can go with the slightly larger cams if you wish since you have more displacement than what the cams were originally designed for.

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post #14 of 26 (permalink) Old 02-15-2017, 10:52 PM
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I'm just glad I didn't see a Thumpr in the options list I would've had to string phrases together with expletives and words like Noooo! and run!
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post #15 of 26 (permalink) Old 02-15-2017, 11:30 PM Thread Starter
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Thanks for all of the feedback. I'm torn. There are pros and cons each way. I think I am convinced roller is worth the extra expense over flat tappet, and the reduced base circle retro rollers seem a bit gimmicky, so I am back to my original choice (XE266HR or something similar).

Decision constipation is tough. I'll let you know how it works out.
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