Mikelly Posted November 4, 2001 Share Posted November 4, 2001 Well Isky hasn't contacted me in a while, so I'm gonna be looking elsewhere for a cam. I think I'm leaning towards KEEPing the hydraulic roller setup and just swapping the cam out. I'll be giving competition cams a call in the near future, as I want to swap that cam and go through the bottom end in December. What do you guys think would be a good cam choice (Hydraulic) with a 383 stroker using final compression of 10.1:1, dart aluminum heds with 72cc chambers, 215 cc runners, amd 1.5 roller rockers with hydraulic lifters... I'm currently running Isky cam # 201282294. My motor surges in 6th gear running anything less than 2000RPMs.. Mike Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 4, 2001 Share Posted November 4, 2001 With 215 on the intake side you have air flow to burn. To get a cam big enough to really take advantage of the heads, you will most likely loose a bit of HP in the low end do to bleed off. I think until you build another point or two of compression, any cam change may actually may be a sum total negative in additional power production. My point is, if you get enough cam to compliment the cubes and heads you already have, you might possibly benefit from some additional compression. When you freshen the low end, it there any chance of new pistons in the future? If there is I have a good comparison cam for you. (Currently running in a 1978 280, with 386 cubes.) Quote Link to comment Share on other sites More sharing options...
Guest RON JONES Posted November 4, 2001 Share Posted November 4, 2001 Mike give this Guy a call http://www.camcraftcams.com My Buddy uses this Guy all the time and has great results With his cams.He can hook You up with a cam that is custom ground to the specs you need for Your combo. [ November 04, 2001: Message edited by: RON JONES ] Quote Link to comment Share on other sites More sharing options...
John Scott Posted November 4, 2001 Share Posted November 4, 2001 I've done hours of calling listening etc. Not realy a consistant science, is it. The only way to get a better low end is to get some of that duration out. The down side is you lose the upper end. A wider lobe sep angle will help clean up the idle, but the tighter the angle the sooner harder and more compact the power comes on. Solid designs can run a bigger cam than equiv. hydral. The cam that AFR uses in their advertisement is CC # CSXR288HR-10 236/242, 520/540 on 110 lobe sep. You'd still have a pretty nasty idle due to the 110, but the smaller duration would help. I'd guess the power range to be 2-6000. They claim 500+hp 500+ ft lb. I agree the 215 heads your lift could be a lot more than this profile. Custom grind! Isky and CC finally agree on my cam. Coincidence? Probably. JS [ November 04, 2001: Message edited by: John Scott ] Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted November 5, 2001 Share Posted November 5, 2001 Mike, Are you wanting a cam for racing or hwy cruising? High Lift, Long Duration & narrow LSA all point to a high rpm power band & a peaky power range. I agree w/the aforementioned posts; you'll have to comprimise on the duration & LSA as your current cam is causing the cyl's to bleed off prematurely at lower rpm's..thus your low rpm surging. We all want hwy cruising when its convienent & we want all out racing when its required: but you cant have your cake & eat it too (I hate it when someone tells me this). Your cubes, your cyl.heads & pistons wont allow low rpm curising if your using a cam that compliments the rest of your package: it all boils down to "how fast" you wish your engine to reach peak power. If you want a cam that allows low rpm cruising then you'll have to use a cam w/a wider LSA which will give you a broader power band...but then you're comprimising your cyl.heads ability to breathe: answer-smaller heads...but then your diminishing your high rpm peak power & your ability to get there quicker...but then your: and so on, and so on. A wide LSA, comparable lift & moderate duration equal a decent low rpm power range but a wide power band. Just the opposite will give you a crispier/faster reving engine w/a peaky power band at the cost of low rpm power. Unfortunately if you want both-your gonna have to purchase a set of 4 valve Arao cyl.heads....come on-cough it up! Their only $5k! Kevin, (Yea,Still an Inliner) [ November 04, 2001: Message edited by: Kevin Shasteen ] Quote Link to comment Share on other sites More sharing options...
Mike C Posted November 5, 2001 Share Posted November 5, 2001 IMO, you are going to have a hard time with a carburetor and the .50 overdrive. To get a big enough cam to pull 6500 rpm, it's going to want to cruise 2500+. The best fix, albeit not cheapest, is fuel injection. Or maybe a set of 4.30 gears? AS far as Comp hydraulic rollers, I like the 286HR, with 230 degrees at .050 and .560 lift or the XR288HR, 236/242 and .510/.520. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 6, 2001 Author Share Posted November 6, 2001 Wait a minute...What do you mean I can't have my cake and eat it to???? What I would really like is to be able to use sixth gear cruising below 2K.. I'm really not sure what to do at this point...I'm gonna call Ron's contact later this week and see what his recommendation is. Might have to go solid or get a different set of heads... Thinking the cost would be about the same. If I go solid I'll try selling my valve train again HERE first... Mike Quote Link to comment Share on other sites More sharing options...
Mike C Posted November 6, 2001 Share Posted November 6, 2001 The solid roller will let you reduce overall duration while keeping your top end. My 280AR solid roller (230@ .050 and .550 gross lift) idles better and pulls 500 rpm higher than the bigger hydraulic rollers. Big carburetors just don't like low engine speeds. One option (I am assuming you have a Holley carb?) is to switch to a modified 750 or 800 Q-jet. They are much better at low and mid atomization, cruising and idle than a Holley. JET sells a stage III Q-jet that would probably help immensely. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 6, 2001 Author Share Posted November 6, 2001 Well Mike that beggs another question... I'm swapping to programmable fuel injection.. You guys think this will help solve that surge issue? Mike Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 6, 2001 Share Posted November 6, 2001 The first Chevy 350 I built years ago surged in 4th gear. I did every thing and nothing helped. It turned out the HEI module was bad. I felt pretty stupid! Hey, it was on a Monday, the dog bit me, I didn't call Kim in Idaho, the wife was a bitch (note "was"), the sun and moon not aligned, it was a blue truck, a, a,a,a,..... Phil what's for lunch? Quote Link to comment Share on other sites More sharing options...
dsommer Posted November 6, 2001 Share Posted November 6, 2001 Mike C Can you tell me more about your cam AR 280 who is the manufacturer of the cam also what is the operational range of the cam. Where can they be purchased? Also what heads are you running the problem I’m running into is finding a set of heads that will accommodate the high lift of a solid roller. I was looking at Edelbrock RPM’s but they would need the springs changed out to run a Comp Cams p/n 12-769-8. Would you recommend a smaller cam for street use? Any way if there is a site out there where I could research the cam AR 280 it would be appreciated. ds Quote Link to comment Share on other sites More sharing options...
Mike C Posted November 7, 2001 Share Posted November 7, 2001 The mechanical roller is a Comp Cams 280 mechanical street roller. It pulls 6500 rpm or so in first gear. It idles at 800 and makes good low speed torque. My only complaint is valvetrain noise, but I am switching from stamped aluminum valve covers to cast aluminum which should reduce noise significantly. ( I HOPE!) I have a set of GM 492 casting heads that have been ported. They have 2.02/1.6 ProFlo undercut stem valves and titanium 10 deg retainers with Crane 11752 gold rockers that clear 1.65 springs. I have 1.45, but they contacted the body of the cheaper Crane rockers. I have had good luck with lash staying very consistent and a set of stud girdles could be added that lock lash in even better. How much money do you want to spend? Dart aluminum or iron heads can be had with 215cc intake ports, 2.05 valves and springs sufficient for mechanical rollers for about $1000. The motor has 9.5:1 flat tops and makes about 425hp at the flywheel and 375 or so at the wheels. It runs 12.7's at 110 with a 2.0 short time and weighs #3500. It was a FAST street car when it was built in '88, but times change. comp cams chevy mechanical roller cams Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 9, 2001 Share Posted November 9, 2001 I am going with a Doug Herbert solid roller that has a .502" lift and a 260 duration(can't remember duration for sure) I have a 1/2 set of 1.6 and 1/2 1.5 so it should work really nice with my Muncie and 3.73 from idle though 6500. Quote Link to comment Share on other sites More sharing options...
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