I'm preparing to replace the 5.0 in my firebird se with a brand new GM 5.7 crate motor. The question I have is will any update need to be made to the existing ecm in the car to accommodate the new slightly larger motor? The new motor will have a Holley 4160 carb. No efi. Thanks in advance. IanB

 

If you're planning to run a carb, what are you retaining the ECM for?

 

What car? What engine is in it now? (which 305, that is... carb? TBI? TPI? what year?) What "crate" engine are you considering?

 

I bought this firebird se back in 1998 from the original owner,it has the stock 305 with a Rochester quadrajette 4 barrel. The motor I'm getting is GM #19433033, 5.7 nearly turn key.

 

I just put the same exact motor in my 84 Z28…your ECM is now just a box with outdated 80s tech in it. I had my trans rebuilt that it will go into overdrive on its own. Question…did you upgrade your fuel tank and pump as well?

 

I'm hoping to keep a mechanical fuel pump on the motor to start,are you happy with the motor you bought?

 

The transmission is a 700 r4

 

Sent pics of the motor to you PM

 

You can't run a Holley carb while keeping the ECM operational...

 

I’m no fuel pump expert but I am guessing that stock 305 pump isn’t up to the task. It wasn’t really an option for me to stay mechanical. Aftermarket mechanical might be an option? I went with an in tank electric pump. Perhaps some of the wiser ones here could provide you some guidance on that.

As far as am I happy with the motor. You bet, absolutely. Dressed it up a little with different valve covers, air cleaner, etc just because it’s kinda boring looking out the crate. However any reasonably affordable option is better than the bag of 🐕 💩 stuffed under the hoods of the early 3rd gens.

 

The stock mechanical pump is fine. Yerbasic parts store replacement piece. One worked great on the 400 (big cam, 800 CFM Holley carb, etc.) I had in my car for many years. I WILL add however, that I had a lightweight fuel pump drive rod in it; I had this one https://www.summitracing.com/parts/mor-65750 although there are several others that are similar. I also HIGHLY recommend an insulator such as https://www.summitracing.com/parts/ctr-85-010 (I made one like this out of fiberglass material) to prevent block heat from making the fuel boil off in the carb.

"Dressing up" is for poseurs. No thanks. Krome don't bring the money home.

 

Did I say chrome? No I did not. In fact I took that ugly crap off mine. But here we are getting WAY off topic. I got a better idea…we put the rulers away and help this guy build a cool car. Isn’t that why we are here in the first place? To share and learn? Who knew…

 

Doesn't really matter whether "dressing up" happens to include krome specifically, or not. I merely quoted the old oval-track racers' adage. Krome, or any other kind of "dressing up", won't shave a .001 sec off of a lap time or a ¼ mile ET. Might even make it WORSE. Waste of money, at a certain level. "Help this guy build a cool car" means steering him away from things that waste money ("dressing up") and directing him toward things that make his car WORK better in some way.

Now, if his purpose for his car is those "square inches of krome" contests they have in big parking lots on summer Friday evenings, that's one thing. For everything else, "dressing up" is merely a distraction, a shiny thing out in the field off beside the path of truth and usefulness, to be avoided by all who aren't easily distracted by shiny things.

 

👍🏻

 

Much thanx to all that replied you all gave me some great info. I'm in no way a chrome fan I'm planning on keeping this motor as dark as can be.