i have an 87 camaro with a carbaurated 305. i already switched the carbuarator to a holley. what i need to know is what else does the computer control, and would it be best to use the computer and old distribitor and coil, or get an HEI distributor and coil and MSD box, and not use the computer?

 

If this is primarily a street driven car, the best carb is the original computer controlled unit. If you have a manual transmission and drag race regularly, then a mechanical secondary carb may be an acceptable alternative. If the Holley you installed is a vacuum secondary type, you did yourself no favors, and probably a good bit of harm (at least to your wallet).

The computer controls the mixture ratio of the carb and the timing of the distributor. It also locks up the torque converter if auto transmission, controls the opening of the EGR valve, and directs the A.I.R. flow to either the exhaust manifolds or converter as required.

The computer needs input from the carb throttle position sensor, distributor pick-up, manifold pressure sensor, barometric pressure sensor, O2 sensor, and coolant temperature sensor. If it is missing any of these inputs, it will not do the other functions properly and will go into open loop "limp home" mode. If you did not replace the distributor with a vacuum/mechanical advance type unit, you are not getting proper ignition timing. There is a little bit of advance built into the ignition module, but it won't be enough for regular driving, although you can get by with it in drag racing if you set the high RPM advance where it should be.

If in proper working order, the computer controlled carb is not holding back any stock 305 out there. The stock exhaust is the #1 culprit, with air cleaner and cam coming in a close second and third. You have to be modified to the point of making unstreetable power before the carb becomes the limiting factor, and even then it could be argued that you haven't reached that point.

 

the original carb had problems and it wouldn't run. we rebuilt it a couple of times and it kept leaking gas and stuff, then we tried a couple of different ones from a junk yard and couldn't get it to run at all, so i bought a holley carb and put on it. and i already removed the EGR valve and AIR system. so basically you're saying that i should just do away with the computer since its not working right or hardly doing anything anyways?

 

While it is true that your computer isn't doing anything now (nor hurting anything), what I'm saying is you gave up on the CC carb way too soon. By the time you get the Holley combination running right, you will have spent more than you would have sending the CC carb off for a professional rebuild, or what you would spend on a professionally rebuilt replacement (assuming you buy new parts to get the Holley set-up running). Gas mileage will be worse, and you will not be emissions-legal (might not be an issue for you now, but very well could be in the future).

Is your Holley carb VS?

 

it runs fine with the holley carb now. i bought it used for like $100 and it was freshly rebuilt, and it has ran fine ever since.
also since it won't be driven very often, other then to race, i'm not that worried about gas mileage. emissions are not an issue here, besides i already removed the EGR valve, AIR system and catalytic converter.
you seem to just want to talk about the carbuerator but its already on there and runs fine, i really just need to know about the computer.

 

The computer is now brain-dead. You can leave it there, or remove it. The gage signals don't go through it. Since, as you say, it "runs fine", you should already have a fairly good idea that the computer isn't hurting or helping anything.

It never hurts to include information about how the vehicle is going to be used, what your goals are, what restrictions you have to meet, etc. The subject line is still a bit confusing, I'll have to admit. What questions do you really have about "305 to 350"?

 

sorry about the confusion and stuff, but i basically need to know if i should leave the computer to control the ignition or replace it.

 

The computer is not controlling the ignition. The only advance you are getting is the "limp-home" advance built into the module itself (advances a little bit with higher RPM).

If this is primarily a strip car, and you aren't too concerned about street manners, you can adjust the timing to 34-36 degrees advance at high RPMs and let it go at that. You may get some starter kick-back. You can add an MSD box that has start mode retard if you like (Digital 6)

The best route would be to get a proper mechanical/vacuum advance distributor.

 

vacuum advanced distributor and eletric out of tank fuel pump thats what i did any way and then i gutted the computer and the harness

 

dont forget the advanced curve kit for distributor