Hey there everyone, going from the LG4 to a 350 with a non CC carb, and electrical stuff I need to worry about?

 

Why would you want to do that?

You want worse gas mileage?

You want to spend a bunch of money to get the same or less performance?

Why would you want to do that?

Fix/improve the air cleaner flow, beef up the ignition module, coil, & wires, tune it with rods & hanger; leave the CC stuff alone.

Unless you don't intend to drive it.

 

Because I have one for free and the motor will not be fed well underneath the stock carb. Thanks for the criticism though.

 

Say I was to go with the stock qjet would it be able to supply a?
355 4 Bolt with
Comp Cams XE268
Vortec Heads
Weiand Stealth Intake
Hooker Cat-Back
Edelbrock TES Heads

If so would I still need to run EGR or no? Because if possible I would like to aviod it. Also assuming I was going to go the Manual 750 what would need to be done? Finally if the stock doesn't work flow enough what would be recommended as a replacement?

 

Think of it as "insight", not criticism.

Unless you have a MIGHTY healthy 350, the CC system will feed it just fine. If you haven't yet, take a look at the mag articles on the board by Steve Green (have "Stroke in the Desert" in the titles). He fed a healthy 383 with the CC equipment. Unless you're building something more radical than that, and it isn't intended for regular driving, you're performance-level at best and dollars behind with any other system.

That's all I was intending to convey.

Having a "free" carb isn't the end of your expendentures. It's been covered several times on the carb and tech boards, but you need to use a non-CC distributor as well. For what it would cost to convert to non-CC (assuming you buy new parts), you could get an aftermarket manifold for the CC q-jet and out-perform the non-CC carb on a stock manifold. "Free" parts are typically used, which means they usually require rebuilding, so add that to the cost of conversion (at least, no worse than a wash if you rebuild your CC carb).

Whichever way you go, the ignition should be upgraded, so that's a wash and I'm not including it in the comparison between CC and non-CC costs.

If you only want to know what you have to do to do what you want to do, get a vacuum/mechanical distributor and (if automatic tranny) figure out a way to lock up the torque converter clutch.

If you want ideas on how to make your combo perform its best, ask questions on this board and consider the responses you get. There are a lot of graduates of the School of Hard Knocks that frequent this site.

 

I see you re-posted while I was typing.

The CC system would work fine with that combo. The Vortec heads would require a special manifold, but that's the case with either carb. The EGR would require plumbing exhaust up to the intake manifold, but that isn't too big of a deal. I'm not a great fan of Vortec heads, but that's another topic.

The q-jet has the potential to out-flow a 750 Holley.

 

Thanks guys! So then here is my question to you guys, I have this 350 sitting in my car with the low profile weiand stealth intake with the spreadbore/squarebore intake and no carb on top and the stock carb sitting on the work bench what would you do if you were me?

 

 

Okay, I got carried away with my tone there. Sure, you can "drive" a non-CC system. But, for the bucks spent, the CC system is a good choice if it's working okay right now (i.e., hasn't been butchered).

All to often, we fall into the trap of "dump the computer", when it really can be made to work quite well. If emissions testing and inspection is a reality, and it is for a bunch of us (around 50% of the people who responded to my poll last month), you don't have much choice, anyway. For a daily driver, I maintain CC is a better choice than mechanical open-loop.

Back to Fade's last question: The Stealth doesn't have EGR capability, so the computer will have to be "fooled" into thinking one is there - not too big a deal, just keep the solenoid connected to the harness and keep it out of the way. You'll still need an O2 sensor (and the other sensors on the firewall) so the computer can do its thing.

Or, you can go ahead and put the Holley on with a vacuum/mechanical distributor and go "old school" with it. Either get a TCC lockup kit, or rig up a switch to let it work for the cruise times.

 

So if I was going to go with the Mechanical Carb what would I need to do with the wiring and ECM that the car is using right now to cure any error codes or nasty little surprises that may come along?

 

Error codes will be a constant. You "cure" that by taking the bulb out of the SES light.

Wiring you bundle up and tuck out of the way (or you can unwrap it and cut off what isn't being used, then rewrap it).

The ECM will be brain-dead. You can leave that extra 8 ounces of weight were it is, or take it out.

"Nasty surprises" are part of the learning process. You've avoided most of them by coming to this board, but it's almost impossible to foresee what's going to happen after you get started on this process (like what that carb is going to do when it first sees fuel pressure). If you've done any work on cars at all, though, this won't be that difficult. If you don't know how to change spark plugs, though, you're in for a long haul (that isn't intended to be a slam, so don't take it that way).

Can't say I'd recommend it still, though. But, that's just my personal bias.

You've never said what kind of tranny you have. If auto, you'll need a very "loose" converter, or the mechanical secondary carb is going to be one of those "nasty surprises".

 

The tranny is a 700R4 but I was going to run the Painless Lock-Up kit with it so I wouldn't be so loose. What do you mean by the fuel pressure, should I change fuel pumps or leave the stock one on?

 

Nah, just saying with a used carb, the first time you go to start it may result in a fuel shower. A rebuild before install will help reduce the chance of that. You'll be fine with a standard mechanical fuel pump.

What I meant about the tranny is, mechanical secondaries and auto trannies aren't the best combo, especially for a street car. This is a WOT from a standing start situation. Strip-only cars with 5000 rpm stall converters do fine with them because the engine can handle the sudden air supply because the converter lets the engine spin up. Manual tranny cars can also tolerate the mechanical secondaries.

Generally speaking, a street car with a tolerable converter should use a vacuum secondary (not directly mechanical) carb. Holley and Demon vacuum secondary, Edelbrock Performer and Carter, and q-jets all fall into that classification.