Visit The Dirt Forum for More Information

Author Topic:   Cam choice for small block chevy
o5racer
Dirt Freak

Total posts: 402
posted September 11, 2005 08:53 PM  
I was thinking of trying a different cam for next year. Track is a 5/16 dirt medium banking. 3400 pound streetstock.
Heres what I have now. 11-1 360, .060 over 3.48 stroke, 6 inch eagle rods, speedpro H140CL flat tops. Heads are fully ported 492 cammelbacks. 2.02/1.6, Intake flows 212 at .550 exhaust flows 175 at .550. The intake and exhaust will flow a little more at .600 and .700 but but its a very small gain. 218 at .700 on the intake and 182 on the exhaust at .700. edlebrock 2101 intake(untouched by rules) with a vac secondary 600 carb. 1 5/8-1 3/4 stepped shoenfeld headers. Currently running a 7.48 final turning 6300 to 6400 depending on the track with a glide and a hollow converter.
Current cam is a midwest #1. .504 lift I/E, 256@.050 intake 264@.050 exhaust. 105 lobe seperation. lash at .026. I am running 1.6 rockers so the lift comes out to .537.
I have ran this cam for several years with good results. Would have finished 3rd overall but the tranny broke on the parade lap on the last night so i ended up fourth. For the most part the power is good but as always I could use more and was wondering if a different grind would work better for my combo. I read somewhere about long rod motors running better with more lobe seperation. Would going to something similar in lift and duration but with 106 or 108 work better than the 105 im at now? Would it be better to have more lift on the on the intake or exhaust? Alot of the cams I have been looking at had more on the exhaust but a couple had more on the intake.
Thanks
Nick

CLBaker25
Dirt Maniac

Total posts: 193
posted September 12, 2005 08:36 AM  
We got a cam from camcraft cams and are very happy with it. It makes a ton of power with a limited carb. I would give them a call and see what they think.

nine finger
Dirt Forum Racer

Total posts: 76
posted September 12, 2005 10:55 AM  
flow numbers on head are off should be better than that. find a new porter.

racer17j
Dirt Forum Champ
Total posts: 5390
posted September 12, 2005 03:04 PM  
The heads are going over to sioux city this winter to see if they can do more with them so they may improve slightly.
How does the lobe seperation affect things?
Thanks
Nick

chickenlittle
Dirt Full Roller

Total posts: 64
posted September 12, 2005 07:10 PM  
Lobe separation will increase lowend torque and power. It will usually decrease the topend some. Depends a lot on the duration that you run with it. Also will help the idle if it is wider. You can use a LCA as wide as 108 with good results. You can go with a shorter duration too. Will help pull off the corners if you can get traction. The longer duration with short LCA gives good top end but kills low and mid range power and torque. If you can't keep the revs up you are better off running less cam with a wider LCA. Especially with the limited carburation and heavy car.

[This message has been edited by chickenlittle (edited September 12, 2005).]

nine finger
Dirt Forum Racer

Total posts: 76
posted September 12, 2005 07:30 PM  
your combination overall looks pretty good. where does the motor need help? off the corner or just more power everywhere.you are probably being out run by motors with more compression and better heads. try 1.94/1.5 valves i know this does not sound right but those big valves in those heads really shroud the incoming air. have the heads been angle milled they need it to raise compression. dont look for a cam yet, you have other stuff to work on first. will check back in a couple days.

ryan
Dirt Forum Champ
Total posts: 776
posted September 13, 2005 08:50 PM  
Nick stay away from the #8 at our track anyways it blows. He's at 11 to 1 now and thats the limit at our track as far as the heads go he can run worked over double humps or stock bowties. Spend some dough get some lighter weight internals and spin it hard. You don't think the boys ahead of you turn 6300 do you? If you got some cash check out this site..... http://www.castheads.com/disguise_work.php

DJR22
Dirt Maniac

Total posts: 111
posted September 13, 2005 11:13 PM  
I can't say I've ever thought of that one...but I'm not too sure the joys of winning are worth that much to most people. Still interesting though.

------------------
-stand on it-

o5racer
Dirt Freak

Total posts: 402
posted September 14, 2005 08:15 PM  
Ryan, it wouldnt suprise me if one of the cars that finished ahead of me had them on. Probably a few in the latemodels to. Ill stick with my old 492s though. Now I just need to get that 38# crower in my garage in useable shape. For now though Im just trying to get as much info on cams as I can to I can make up my mind. I was thinking about something in the 248-252 range around .560-.580 or so. I havent made up my mind on the seperation though. If I go with a split pattern cam should it favor the intake or the exhaust? I have seen several grinds that go either way. Thanks for all the replys. Keep em coming.
Nick

nine finger
Dirt Forum Racer

Total posts: 76
posted September 15, 2005 04:03 AM  
05 it depends on how the motor is built. on a restricted two barrel you would have to run more intake, but it is rare.it all has to work together to do what you need it to do. now where do you need moore power. off the corner down the straight or top end.

o5racer
Dirt Freak

Total posts: 402
posted September 15, 2005 06:58 PM  
As for where I need more power I would say pretty much all around but mainly low and mid. I do have a 4 barrel on now and as far as I know we will still be able to run them next year. Im thinking about either 106 or 108 but I am not sure.
Nick

nine finger
Dirt Forum Racer

Total posts: 76
posted September 15, 2005 09:24 PM  
if you need more off the corner you can roll your cam up four or five degrees. assuming that it is not already done.the difference of one or two degrees lsa is nothing to worry about yet.comp cams have a tight lash series of solid cams you need to look at.keep intake duration in the 244-248 range exhaust 252-254 range. dont worry about lift its more of the result of how the cam is ground than it is an indication of how its gonna run.as alwayse advance the cam four to six degrees.

ryan
Dirt Forum Champ
Total posts: 776
posted September 15, 2005 10:07 PM  
You could try the cam I'm running from Shaller (530/550)ultradyne copy. I like it but its a little more pricey than your midwest. More than likey the cam the guy ahead of you in points has. Your ported double humps at .550 flow what bowties flow at .500 stock.

[This message has been edited by ryan (edited September 15, 2005).]

racerman707
Dirt Freak

Total posts: 374
posted September 16, 2005 05:55 AM  
Are you sure it's the cam you need help on and not the carb? I had my carb worked on and couldn't believe the difference off the corners and pulls HARD down the straights.

tlkdlw
Dirt Full Roller

Total posts: 42
posted September 23, 2005 12:35 AM  
252in/261ex Duration @.050 540 lift
106 lobe sep. advance to 99 This is a excellant
mid and top but the advance gives great low end tork good from 3000 to 7200 RPM

bamadirt
Dirt Newbie

Total posts: 2
posted September 23, 2005 02:09 PM  
05....this is what we do..for a cam....call
one of the mager cam grinders (like comp cams)....and do as they say....LOL

Back to the Archives