silver79

JUST GOT BACK FROM PICKING UP MY 79 L-82 FROM MY MECANIC. HE CHANGED THE TORQUE CONVERTOR FROM STOCK TO A 2000-2200 STALL AND AT THE SAME TIME I HAD HEDMAN HEADERS 1 5/8 PRIMARIES INSTALLED WITH AN H-PIPE THROUGH 2 1/2 INCH DUALS. FIRST THE SOUND IS ALOT QUIETER BUT THAT IS NOT THE PROMLEM MY MALLORY IGNITION BOX FAILED I RETURNED TO THE STOCK (IN PERFECT SHAPE) IGNITION SET UP AND WENT OUT TO DO SOME TESTING WITH MY G-TECH. I LOST OVER 1 SEC. IN TIMES BEFORE THE CAR RAN 5.22 0-60 AND 14.02 AT 1/4 MILE NOW 6.59 AND 15.39 WHAT THE HELL?? IS THE CARB TOO LEAN. :confused:

Jvette73

Thats a bummer. The exhaust and converter mods should have defenatly helped the performance. I would say that since the ignition and distributor was changed that that may have had a negitive effect. Not that the original ignition is bad or anything, but by changing it, you now may have different timing settings, advance curve, total timing ect...those things can definatly effect performance in either a positive or negitive way depending on how they're set up. Do you know what your timing setting are now...IE initial, and total in by what rpm?

Clink69

Most probably leaned it out some but not enough to make that much difference.. When they did the headers , what did they remove. Look for the obvious disconnected things, vacuum lines, also check the timing... What do the plugs look like?

Jvette73

Good point. when I went on a Corvette cruise a few months back there was a guy with a 68 that had a brand new zz4 with fastburn heads. It ran good. While at the hotel at the end of the day one of the other cruisers was lookin under his hood and noticed a plug wire hanging off. It turned out that the guy had just changed his plug wires before the trip and had acidentally left one unhooked. Ater hooking it up his car sure ran better the rest of the trip.

BSeery

Yep - check the plugs, wires, and vacuum.

If you went to dual exhaust and headers you must increase the amount of fuel going in.

More air moving out, means more air moving in. Unless you give more fuel, you will be running lean.

If you have Holley, plan on jumping up 2 jet sizes and makeing another run. Keep moving up 2 jet sizes and makeing run until you don't get any more performance, and then go back 2.

silver79

I just looked at the plugs the first one one the driver side closest to the fire wall was abit burnded Itaped it up I might change them but before i will check the timming

silver79

I have the stock rochester I will try to rich up the fuel mixture

isosceles

for rejetting your Qjet, definitely use Lars' tuning papers. It tool .6 off my 1/4 mile time and I'm not done.
Turning those screws on a Qjet only affects idle mixture.

78 Vette

Did you check your total timing? I would set it at 36 total and take it out for a blast. When you set the timing don't forget to disconnect the vacuum advance.