boc23

Hi all,

I have a few questions I hope you can help me out with. I had my engine (395558 2)rebuilt a few years ago and haven’t drove it much. Unfortunately I don’t remember what was done with the engine. At that time I put in a new heavy duty drive line, new manifold, new posi (I think 3:11 or 3:42 gears), rebuilt 650 edlebrock carb and I have a semi high performance cam. I think the heads are 409147 (what does that mean). This is all packaged in a 1971 cutlass supreme convertible 3 speed hurst. I have no push off the line, I can’t burn the tires if I want and it just is real sluggish it runs really rich, you can smell the gas while the car is idling in the garage and it will burn your eyes!!!. One of my friends suggested a 750 carb, hei advance distributor kit and a fuel pump. My other friend suggested getting the heads done or change to new heads, new cam, lifters, roller rockers and pushrod set, and torque converter. What do you guys suggest and if I get new heads what are the best heads to get for my engine. Thank you for taking time to read and help me out!! BTW I want something I can drive frequently, burn the tires and move pretty decent when I want to!

don71

Don't throw a lot of money at it yet. Its likely your troubles are carb and/or distributor related. It might just need to be tuned properly.

I'd start with getting a vacum reading.

Timing checked and set properly.

I'd also want to know what the plugs look like>black, tan what color?

Digging deeper into the carb I would check for proper choke operation and idle characteristics. This is related to vacum. You might have a vacum leak... who knows.

Even further, I would want to see a compression test done. Curious to see what the numbers are.

You should be able to find some performance in your package hopefully. Its gonna take a little attention. Keep it simple for now.

Not knowing what exactly was done in the engine rebuild and not knowing the cam information kinda hurts. But you can start with a check of the things listed.

boc23

I just changed the plugs, they were tan. Theres no choke. I do have a couple of vacuum leaks and it's running real rich.... burn your eyes rich!

oldcutlass

What timing settings are you running? Is the HEI connected to full battery voltage, in other words no resistance wire? If your timing is declined your engine will run rich.

joe_padavano

Saying you have a "three speed Hurst" implies you have a manual trans, but then you talk about a "torque converter". What drivetrain do you have, exactly? Manual trans or AT? The shifter is irrelevant. Tell us what trans you have (TH350, for example, or Muncie 3 spd manual). As for the rear gears, there was no such thing as a 3.11. You likely have a 3.08 or even lower numerical axle. That's your first problem. Second, stop listening to your friends and learn how to tune the car so all the parts match and work together.

Running rich at idle is unrelated to how the car runs under load. If it really is running rich at idle, that usually just requires adjustment to the idle mixture screws. Keep in mind that the generic E-brock carbs are set up for Chebby motors. You need to dial it in for something else. You also need to get everything working properly (like the choke). There's a lot of adjustment possible on the E-brock carb. Download their tuning manual and read it. Don't start throwing money and new parts at the car until you get it running correctly with the combo you have.

Arrowstorm

As far as the edelbrock goes, it sounds like it's just dumping fuel. If it is new (not rebuilt), you likely just need to get yourself a vacuum gauge and dial in the fuel/air mixture to the sweet spot of about a steady 20 inches. Also, if it is really sluggish, you might also need to adjust the floats. Scour the internet to find out how edelbrock floats must be adjusted, that's what I did. I run a 600 cfm edelbrock on my 72. And no matter what anyone says, you WILL need to readjust the F/A mix from time to time. Some guys swear by Edelbrock and some by Holley, but I've heard both sides of the table complain of having to make readjustments, especially after weather changes.

If you bought a "rebuilt" carb or you got a padna from down the street to rebuild it and charge you a couple hundred bones (like my uncle did for his Holley on a chevy 350 for his boat!), you might want to have a look inside the carb to make sure it's not pitted with gaskets broken all over the place.

You also need to check your timing based on what kind of ignition you're running (HEI or points).

Like Joe said, check all the simple stuff before you start throwing money at it.

Fun71

And fix those vacuum leaks before you do anything else! You can't tune an engine that has excess air bypassing the carburetor.

Octania

My 403 was running burn-yer-eyes rich at first
low power, would not match a modern V6
Overheated on a 2 mile test drive.

A lot of cam [286?] and good compression- like 9.5 or so.
HEI off the computer
Rebuilt 403 Toro carb
refused to idle below about 1200 RPM, any lower and vacuum would drop off below 7 and then she dies. While burning your eyes.

Sound familiar?

boc23

I have fixed the leaks and it runs a little better. I'll do a compression test this weekend. I did find out I have 3.08 gears

olds 307 and 403

Were the pistons changed on the motor rebuild? If so, do you have the part number? If it is a HEI distributor, what is the timing set at? Even with 2 something gears, it should roast the tires.

boc23

Bad news is I can't remember what was done on the rebuild. Is there a way I can get the part number? I'm going to do a compression test and check the timing this weekend. Also need to know what kind of cam was put in, is there a way to check?