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73-87 Chevy _ GMC Trucks => Performance => Topic started by: mwood150 on April 17, 2009, 02:45:06 pm

Title: 85 c10, 305 to 350. Need ECM mods?
Post by: mwood150 on April 17, 2009, 02:45:06 pm

I have the carbuerated CCC system with MC solenoid.  Previous owner replaced the stock 305 with a 350 goodwrench engine.  He left all the electronics the same.  The truck runs good, but seems very tame.  I was wondering if there was something I should do with the ECM and Sensors to make it better suited for a 350?  If it matters - all I want is decent power, and I use it primarily for towing a boat. 


-Mark

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: Russ130 on April 17, 2009, 02:56:57 pm

Unfortunately some 350's are very tame and offer no more power than their 305 conterparts. You could try and swap out the ECM for one out of a 350 equipped 3/4 ton truck. The 3/4 ton would almost certainly have better performance than a 1/2 ton's. I have also heard you can get the chip reprogrammed but I am not positive about that. Just a couple thoughts for you.

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: mwood150 on April 20, 2009, 07:50:31 am

So then there is a difference in how the 305 ecm and 350 ecm is programmed, but no difference in the sensors?  Please someone tell me where I can get a chip or a good deal on a 350 ecm.

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: VileZambonie on April 20, 2009, 11:19:51 pm

Don't waste your time. If you want to wake it up cheap get a new ignition system and replace your carb. A decent exhaust system will help too.

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: mwood150 on April 21, 2009, 01:43:32 pm

In other words, do away with the computer stuff alltogether?

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: mwood150 on April 21, 2009, 01:50:13 pm

If I was to do that, what is a good carb that will bolt up to the stock manifold?  I know, most people say this is personal pref, but I dont have personal pref right now.. So whats an all around good performer?  Remember, I need to tow, its not a daily driver.

Thanks!

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: Captkaos on April 21, 2009, 02:25:15 pm

I would ditch the CCC and put a normal Q-jet on there, it will bolt up to the current setup, minus the control.  I would ditch the ESC distributor also.

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: VileZambonie on April 21, 2009, 04:53:22 pm

Are you good at tuning carbs? The easiest to tune is the edelbrock (carter AFB). The Q-jet can be dialed in nicely also but requires more disassembly.

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: Stewart G Griffin on April 21, 2009, 08:07:43 pm

Also, what rear diff gear do you have;  That could make a big difference.  As far as tame, i was able to turn a 16.8 1/4 mile time last summer with the crate 350(completely stock) and that was with 2.56 rear and cheap off-brand tires(which spun a little).  We also have to remember the 3800-4000 curb weight.  This was also,as i now suspect, with the engine in sick form (pls see my other pitiful post entitled "new problem" for more info).

Title: Re: 85 c10, 305 to 350. Need ECM mods?
Post by: mwood150 on April 22, 2009, 12:06:18 pm

My rear diff was 3.08.  It could not tow at all whatsoever.  I put in a 3.73, and things are much improved.  I was just wondering about the computer because that would be an easy upgrade for me if it would make a difference.  The guy that had the truck before me spent a good amount getting the carb rebuilt and tuned, so I kinda hate to ditch it right now.  As soon as it starts crapping out I will probably go the computerless route.