Hello Board:Is it possible to have a lumpy cam in a 8.1 comp motor without a lot of problems? I have a stock 403ci olds thats going into my 33 olds,would really love to hear that sound that only a lumpy cam can bring.Maybe I'am just dreaming. Anyway. Thanks In Advance Oldeman
Ran a 300H Monarch years ago in a 9 to 1 SBF - cool sound - absolutly NO bottom end. Compression helps with the low RPM torque. Lumpy cam blows off a lot of compression at low RPM so with 8 to 1 there will not be much there and might be tough to drive. I love lumpy cams though.
Well, yes, you can. But that's about the only thing you'll have is a lumpy sounding motor. In order to work well, a motor needs to have components that compliment each other. Compression, induction, valvetrain, exhaust, ignition, etc need to have some semblance of "matching" in order for a motor to do more than just make a lumpy sound. But if that's all you're after, go for it.
The rest of the drivetrain is probably more important than the compression ratio, when it comes to cam selection. Look at the RPM range of the cam you want to run, and decide if you're willing to run the torque converter and rearend gear necessary. Also think about if the induction/heads/exhuast will work well at that rpm range. If you put a long duration cam in an otherwise stock car, you lose the bottom end torque, but you also strangle the top end performance, so you have a really bad performing ride.
Somebody I knew told a cam grinder that he wanted a cam with a wild idle. He said he wasn't all that concerned about power or RPM, but he wanted the nasty sound. The cam grinder said, "Oh, just like everybody else." Has anybody tried one of Comp Cams' "Thumpr" grinds? According to their ads, they are exactly what you're asking for -- a wild idle with reasonable performance and driveability.
Look in the circle track grinds. There are cam grinds suited for classes with a compression limit. If I remember right they close the exhaust sooner, and increase cylinder pressure by keeping a little exhaust in the cylinder. Squirrel is right. The convertor and gears are a must, or a manual trans.
Lumpy is nice, if you have the rest of the engine to support it...otherwise just get one of the fancy rev limiters that drop different cylinder at a time, and turn it way down when your parked.
Try a comp cams XE274H. I have had the best luck with the Extreme Energy series cams. As long as you have good ring seal and a tight valve job, to keep the compression in the cylinder, you'll be fine. By the way wasn't Lumpy a dude on Leave It To Beaver??? >>>>.
From reading your question it looks like all you want is that "Lumpy powerful" sound. That comes from lots of overlap and a motor with low compression will not sound "Powerful" at all, more like mushy and like its miss firing. Nothing sound better than the pop of a high compression motor with a big cam, but I don't think you'll get that.
Install a manual choke and run it 3/4's shut TA/DA >>>>. And by the way Lumpy's last name was Rutherford >>>>.
What reduces low speed power: late intake valve closing What makes that rilly kewl idle: high overlap Not the same thing When does leaving exhaust gas in increase pressure: never
In the 50's, when Ya was stuck with Dad's car,cus your rod was broke,to make the run to da car hop drive-in hangout on fridays or sat. nite ,ta see your bud's and make that car sound like it had a sleeper mill hinding under the hood,we took off the air cleaner so it made lots of carb sound and pulled the choke out tell it sounded lumpy,fooled some
Thanks Guys:I think that I maybe knew better but wishful thinking you know.SOooo 403 will be coming apart for a bet of a bore,decking.highing comp. piston And that Lumpy cam.I really can't afford any of this,but lumpy cams RULE.Thanks again Guys. oldeman
All I could hear was wind noise and some latin guy playing maracas in the background... I gotta get new speakers.
Yeah and Lumpy had a cool 40 Ford in Grey Suede in one episode! Got arrested in it when Beav thought they were burglars. (was on TV Land a couple weeks ago)
My high school buddy did this to his dad's olds 455 and dropped the air cleaner wing nut down the carb. It went down the intake and stuck the valve open - busted
These are the cams I was talking about from Speedway. http://www.speedwaymotors.com/p/6615,113_Vacuum-Rule-Hydraulic-and-Solid-SandB-Chevy-Camshafts.html If you hit the link click on the application chart under the picture of the cam. These cams are designed to run with lower compression ratios. Wide seperation angles and note they are installing them advanced. Closes the exhaust valve earlier.....
Probably not what you're looking for (and NOT cheap) but with the compression that low an Isky 5 cycle and a blower would 'sound' cool.
send it out and have it reground....Clay Smith does it. Had a buddie have his 276 (HEMI) reground and it sounds bitchin w/ 7.5-1 compression.....
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