Thread: 1st lumpy idle build, and cards I've been dealt

Tweet

Welcome to here! Lots of sharp guys I've learned a lot from... My first guess would be too lean... That cam should idle fine at 800 in gear... Looser converter will help. If mix is right but still won't run could try advanced key way will give more low end at expense of top end (I think I got that right!). What is the compression?

Others will have better advice...

-Chris

Welcome - this is a great site and I think you'll find us fairly outspoken on everything from cars to "you name it"..

I think you have way too much cam for this application. The 882 head is not going to work. It is a low compression, open chamber head. The 270 degree duration and higher lift is too much for the heads. It will be difficult to drive occasionally, much less a daily driver.

Their web site offers the following description:
“Magnum™ Cam
These cams are very aggressive, designed for performance oriented vehicles where they will see little street use. Stock components are generally incompatible Changes are needed in rear end gear ratios, headers and the torque converter.

270H Magnum™ is a great cam for high performance driving in street machines. The 270H has a rough idle in small blocks and a noticeable idle in big blocks. This is the largest cam you can use with a stock torque converter. The 270H will not affect power accessories, but should be used with headers and a 4 BBL. carburetor. This is the perfect cam for cruising.”

You may be able to use the stock converter - but the 882 heads are your problem.

Just my two cents - others will chime in.

Good Luck,
Glenn

Motor needs minimum 9.5:1 static compression ratio to work with this cam. Agree with Denny, 2000-2500 converter. Ditch the Performer intake. Use RPM or Stealth. Agree with Glenn, there are better heads out there.
http://www.barrygrant.com/demon/default.aspx?page=28

http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html
http://www.4secondsflat.com/Spark_plug_reading.html
http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

Originally Posted by glennsexton

270H Magnum™ . The 270H has a rough idle in small blocks and a noticeable idle in big blocks. This is the largest cam you can use with a stock torque converter. The 270H will not affect power accessories, but should be used with headers and a 4 BBL. carburetor. This is the perfect cam for cruising.[/I]”

If it can be used with a stock converter then this cam should idle in gear fine, and I think they are talking the performance aspect of when power turns on, not if it will idle. I think you have other issues, fuel, spark or vacuum. Check for Vacuum leaks, and ensure your PCV valve is working. Dead miss on one cylinder is mechanical or ignition, find dead cylinder and do compression test to see if cylinder is OK. I wouldn't blame the heads up front until everything else is checked out. Heads may not be optimum for combo, but people have been overcamming smog heads for years and the cars still run, there just dogs.