Cam selection

[dm62409]

Using the master lobe profile catalog thats available online from comp cams is very helpful using the dur @ .050 and .200 figures you can get an idea how quick the lobe ramp is, and the tappet lift at t.d.c. figures at either 106 or 110 Lobe separation angles is helpful in estimating available piston to valve clearance. Good stuff here if you want to spend some time researching lobe profiles and moving separation angles that would benefit your application.

 

[427John]

Why not go to the bottom of the page and then build an engine big enough to handle it?

 

[La Hot Rods]

The last cam I selected for a different brand engine, I went to the comp catalog and and picked the one that said for 10.0 compression great torque in a heavy car with 3500 plus stall.

 

[Gus68]

I emailed comp cams. I'm curious bout what they say. And yes, I understand about over cam-ing an engine. I just did not think this was it. I had a very similar cam in a sb 406 with camel backs that ran hard. Low 12s and a few high 11s. That car was about as heavy and geared the same. Now i know the 333s arent the best heads but they gotta flow simmilar to a set of sb camelbacks. And i know a 409 is a different breed than a small block. But an engine is an engine right? And with 10 to 1 comp. And light pistons, it should rev right?

 

[Don Jacks]

Up to 6,000,no problem,6,500 things start getting shaky,7,000 up,you'd better have good rods,and your valvetrain had better be "dead nuts" if you expect it to live.I'll freely admit that ,like in politics ,I'm on the conservative side.This is based on driving cars to the track,racing the heck out of them,driving them home,and then to and from work for an average of 6 years and 70,0000 miles before freshening up for a quarter of a century.It's your car,your motor,do it your way.You asked for advice.One thing that I found,and maybe it's me,but when the guy at Comp.Lunati,Crane specified a grind for my use,one step smaller worked best for me.

 

[Gus68]

What cam did you go with Don? What do you have for heads? Are you similar to my motor? Hopefully comp will get back to me this week and I'll let you guys know and hopefully get your guys input

 

[Don Jacks]

On my engine,a 380[4.155 bore,3.5 stroke,6.385 rod,KB Icon pistons],I went with a Comp unit that has 267 in.,280ex[224 at .050 in.230 ex.at .050],lift in the .530's with 1.7 rockers,and Rhodes Vmax[adjustable] lifters.The heads are ported 817's with 2.19 intakes,and 1.72 exhausts.The intake will be an Edelbrock Performer RPM,carb,750 Speed Demon.Hp will be in the 430 plus range by 5,500,torque in the 460 range by 4,000.The compression will be in the 10.25 range,and yes headers.

 

[Gus68]

Well I know this is an old post. But I said I e mailed comp and I would let you guys know what they said. Well I actually e mailed them twice and I am STILL waiting for there response! Needless to say, I gave up on them , and, do to the AMAZING service, I probably won't buy a comp cam now.BUT that doesn't mean I can't go somewhere else. So here I am. Still searching and reading about cams.

 

[Don Jacks]

Call Mitch at Lunati[not email,pick up the phone].He just did a hyd.roller for a W for me.

 

[dm62409]

Call Mitch at Lunati[not email,pick up the phone].He just did a hyd.roller for a W for me.

What Don said, pick up the phone and talk directly to the tech line guys, tell them what you want. Comp Cam did two roller cams for the W's for me a few months ago. Good service, beautiful work, no problems.

 

[303Radar]

Follow this link to the Bullet Cams site:
http://www.bulletcams.com/RecForm/index.html

Fill out their form. They got back to me the same day.

Their recommendation is here:
http://www.348-409.com/forum/threads/got-a-cam-recommendation-dont-know-what-to-think-of-it.26601/

 

[Skip FIx]

Bullet also has the old Ultadyne lobes by Harold Brookshire. My 470-'09 has one of their rollers in it, several of my Pontiac motors have their HFT. Their HFT 280/288 is a decent choice for what you are doing. Buddy has one in a low compression 455 and in that bigger motor just a little healthier sounding than a stock cam.

 

[Gus68]

Ok. So I know it's been a while. But I said I would let you guys know what comp says. Well I FINALLY got threw to them. I told them my car heads bla bla bla... And my intended use. I did NOT tell them what cams I have been looking at. They recommended the 48-601-5 . Ha! That's the one I was eyeballing in the first place! I was surprised.

 

[Don Jacks]

If you buy that Thumper and like it,you'll be number 2.Good luck.

 

[Ishiftem]

Yeah, it seems they tell the customer what they want to hear to get the sale. If company A recommends a little larger can than company B, most will buy from company A when in reality a little smaller cam the either company would be a better choice.

 

[IMBVSUR?]

I have seen the big cam thing mostly with Harleys. They would say, my buddy has this cam, I want that. Doesn't matter they have low compression, or stock heads and carb or throttle body, doesn't matter that they ride between 1500 and 3800 rpm 99% of the time. No, they want that cam that is BIG, that has lots of overlap, that doesn't even come on till about 3500 plus rpm. That's real usable to them. Sometimes, you just have to say, Ok, your bike, your money, your decision. Remember that .

 

[Gus68]

Nope. I went into the conversation fresh. I didn't tell him my thoughts on a cam or what I have been looking at. I told em bout my car and the motor and my plans for the car. When they recommended that cam I asked em the questions that you guys brought up. Supposedly, according to him, it should work out well.

 

[La Hot Rods]

So what have the other cam manufacturers suggested?

 

[scott hall]

I have seen the big cam thing mostly with Harleys. They would say, my buddy has this cam, I want that. Doesn't matter they have low compression, or stock heads and carb or throttle body, doesn't matter that they ride between 1500 and 3800 rpm 99% of the time. No, they want that cam that is BIG, that has lots of overlap, that doesn't even come on till about 3500 plus rpm. That's real usable to them. Sometimes, you just have to say, Ok, your bike, your money, your decision. Remember that .

You hit the nail on the head. A lot of them fellers are just this bar to that bar. Want the noise but don’t want to spend the extra to make them work or listen to somebody that does it all the time.

 

[Phil Reed]

Minus-minus!!!!!!!!!!!
My best friend bought a new 72 Sportster with the 61ci engine. Within a year, it was a 77ci engine and the minus-minus cams. NOTHING hauled like that bike!!!!!!!! And he had cylinders for 83"!!!!!!!!!!!!!