Motor's been rebuilt - .030 over - with stock heads, intake, carb dizzy; has headers & 2 1/4" pipes, no cat. What's a good bumpstick that'll give some more power but still retain the computer? I don't wanna mess with new intake, carb and distributor or deal with trans right now ($ tight).

isn the computer stuff worthless if your cat is gone?

Not unless you have after cat O2 sensors. But a cam is gonna throw the lame computer crap all outta whack if you put anything worth having in there. Just save up and ditch the computer stuff at the same time as doing the cam. All you need is a vacuum advance distributor and a new carb.

I ran the Edelbrock Performer cam (204/214, .420/.442) on my '81 LG4 305 car, and the computer had no issues with it. Still idled stock, but had lots more on the top end. I managed 15.1@92mph on that engine, with just headers (Tri-Ys) and dual cats.

Todd

Thanks for the replies.

<font face="Arial,Verdana" size="2">Originally posted by badazz81z28:
isn the computer stuff worthless if your cat is gone?</font>
My understanding was that the comp controlled the ignition advance, carb mixture and the torque converter lockup.



[This message has been edited by the_Z_is_hers (edited December 01, 2004).]

The computers used on Qjet cars are pretty dumb - which is good in your case, because really all they actually "look at" is engine temperature, O2 sensor, and timing to determine what it should be doing. Because of this, you can run basically any cam, heads, intake... you want to, because they have no affect on the computer.

A better place to find info on modding a CC Qjet engine might be www.thirdgen.org (http://www.thirdgen.org)

This site is great, but TGO has a whole section of their board just for computer-related questions.

I'm using a crane powermax 2050 in my 81 with stock computer and carb. I can't tell you how it is yet because I havent finished the swap. The cam has a respectable 218/228 @ .050 and .454/.480 lift. It also comes with a CARB e.o. number for california and is supposively smog legal.

The computer will care if you go to far with the cam BUT...... you have to go pretty far. I've run cams with as much as 230* duration (112* LSA) on computer controlled QJet engines without encountering any serious problems.

The Crane PowerMax 2050, like white81 uses, I have also used. It's a good cam for a computer controlled QJet engine that's got a few mods for better breathing (intake, exhaust, maybe some head work). I think it's maybe a tad aggressive for use with a stock stall converter, but it'll work.

If I was doing this on a tight budget I'd probably also look at the Summit house brand cam with 214/224* @ .050 on a 112* LSA. I haven't used it in a computer controlled QJet engine but I bet it would work just super.