SBF Camshafts

[csxsfm]

Anybody have any experience with either of these two cams: Comp 31-334-4 236@.05 528 lift 110 lobe separation or Isky 381358 236@.05 .512 lift 108 lobe separation?

[shelbydoug]

Yes. I am using the Compcams version.

[csxsfm]

Great.  Guess you like it. I'm looking for good torque from 2500 - 6000 rpm from a sb with 3259 on ported manifold, heads, 11.3 cr with headers.  From your experience would it deliver?

[shelbydoug]

For my application it is fine.

It is in a 347, AFR heads, 1-3/4" JBA headers. 10:1 cr. T/A 2x4 intake.

With only that lift, the cam works fine with the flow characteristics of the heads. They don't need anymore lift. They flow 285cfm @ .500.

So the combination reduces the wear and tear of the valve train. At .550, they flow 295 so going to more lift is pointless for me.


It idles at about 850 and only provides around 14 inches of vacuum.


Yours is closer to a '60s T/A car. Those heads only flowed around 230 cfm race prepped. To compensate they ran a roller lifter cam with around .570 lift. That's probably where you will wind up but yes, it is a good profile to run.

[csxsfm]

You are correct.  Mine is like a vintage Shelby Racing customer motor.  The lift is as far as I want to go.  My days of aggressive parts are over.  Thanks.

[shelbydoug]

You are correct.  Mine is like a vintage Shelby Racing customer motor.  The lift is as far as I want to go.  My days of aggressive parts are over.  Thanks.

Well, the Compcam is by no means a pussycat. It in no way sounds or acts like anything ever put in any street Shelby and in my case is in my '68 GT350 which will never be mistaken for a Lincoln with stripes.

As Robert Conrad once said, "go ahead, knock it off my shoulder" It will run against ANYTHING here short of a blown car, but you know, those cars blow anyway.

[csxsfm]

Is very good mid range torque (2500-5000 rpm) something I could expect?

[shelbydoug]

I would say so, yes,  but it depends entirely on how many cubes you are running. A 289 was never a torque monster.

For the time it was competitive for it's class and it's physical dimensions. Many are now running the original package as a 331 or a 347.


The racers currently like the 331 more because of it's ultimate rpm potential.

For me, I find the 347 is better simply because of the additional down low torque. It has a 7,000 rpm plus capability. I suppose the 331 is closer to 8,000?

Anyway you look at this though you are mixing and matching parts and as such the results are going to vary.


I like the 2x4 Holley combination as raced in Trans-am competition rather then the single 4 3259. It's just a matter of personal preference.


The cam we are talking about is more of a hot street cam v. a full competition profile. It has some compromises but overall is a good, strong performer.

[csxsfm]

289 ci, 2000 lbs car, 6000 rpm or less, autocross/street.

[shelbydoug]

289 ci, 2000 lbs car, 6000 rpm or less, autocross/street.

Compcams says it's a 289 cam. Try it. See if you like it.

Back "in the day", you always had to try the cam. They were constantly getting swapped out because people would be disappointed in them.

I look at it the same way I do "Webers". It/they aren't going to turn your 289 into a 427. I think there in lies the issue.

[csxsfm]

"Back in the day" when racing I experienced some of the cam disappointment.  Just trying to avoid it now that I'm older and lazy.  Thanks for your comments.

[shelbydoug]

"Back in the day" when racing I experienced some of the cam disappointment.  Just trying to avoid it now that I'm older and lazy.  Thanks for your comments.

There is PROBABLY a hydraulic roller lifter profile that will give you more torque and be smoother but I don't know what it is for the 289.

They definitely exist for the 427-8s and the 351c's but basically are 6,000+ rpm cams.

Randy Gillis recommended this cam to me and I would in turn recommend it to you. In a 2,000 pound car it will be an "animal".   

Best!

[crossboss]

Anybody have any experience with either of these two cams: Comp 31-334-4 236@.05 528 lift 110 lobe separation or Isky 381358 236@.05 .512 lift 108 lobe separation?

Both of those cam grinds are older tech (yet, very good). Personally, I would go with a modern hyd roller grind. Yes, I know Randy recommended the Comp cam. He is the master. I had him grind a cam for my 1970 Boss 302 T/A car way back in 1987. IF I were to do it again today, a hyd roller grind would be my only choice in any engine I build these days. Just my worthless two cents...

[Royce Peterson]

Anybody have any experience with either of these two cams: Comp 31-334-4 236@.05 528 lift 110 lobe separation or Isky 381358 236@.05 .512 lift 108 lobe separation?

I think either of these will be a lot of cam if you are limited to 289 CI. I took the same Comp Cams cam out of a '66 GT350 because the customer didn't like the lack of low end torque. I installed a Comp Cams 260H which he was happy with. It was more like 212 degrees at .050" and .498" lift. You can save yourself a lot of grief by adding cubes.

[shelbydoug]

Anybody have any experience with either of these two cams: Comp 31-334-4 236@.05 528 lift 110 lobe separation or Isky 381358 236@.05 .512 lift 108 lobe separation?

I think either of these will be a lot of cam if you are limited to 289 CI. I took the same Comp Cams cam out of a '66 GT350 because the customer didn't like the lack of low end torque. I installed a Comp Cams 260H which he was happy with. It was more like 212 degrees at .050" and .498" lift. You can save yourself a lot of grief by adding cubes.

In a 2,000 pound car with a manual transmission it will be fine BUT picking a cam profile for someone else is like fixing someone up on a blind date.

It's something to avoid.

Largely people are searching for something that does not exist. They can't find it on their own as a result so they ask someone else.