Good morning all. I've been working on a 292 with a 3x2 intake for several years now. I've gotten to a point where I can drive the vehicle for short trips, but I'm intermittently getting a backfire under acceleration once the engine warms up. Its also cut off on me twice at a stop. I think it might have been vapor lock, because it restarted pretty quickly. Ive sent the carbs out to be professionally rebuilt. I called the cam manufacturer and my initial timing is where it should be. (10⁰ btdc) I've been trying to do some research about what else might be causing my concern. I'm wondering if I'm getting an issue from the heat riser ports running under my center carb. I'm using the wide open gaskets, not the truck ones with the smaller opening. Could this be my issue? I'm trying to make the power tour this year and I'm running out of time. Any help would be appreciated. Cam is an isky 301333, Weiand intake. 292 bored .090 over. Red's headers that have been ceramic coated to lower under hood temps, gasket-match porting on a set of G heads.

I have not blocked the carbs back off to run on the center carb since getting them back from Vintage Speed. I just wanted to say I appreciate everyone's help with trying to get this diagnosed. I wish you guys weren't so far away. I'm in the process of removing this intake to sell it. The vehicle will make more power with the 4 barrel. The cool factor of the 3x2 doesn't outweigh the amount of hassle this has become. Thank you all for your time.

I to have been down this road. After spending $900.00 at Vintage Speed for carbs, $400.00 for Eldbrock 553 3X2 intake, and $ 125.00 progressive linkage countless hours tuning I just said the heck with it. I'm running a Holley Quick Fuel-SL-450 VS Slayer. Runs like a Stripped Ape. The flash under the hood is not worth the trouble.

56 VIC  Gene Stoehr Sr.

The last Pertronix that failed on me would not allow me to accelerate but would run just fine idling. I kept thinking it was the accelerator pump in the carb. That was a Pertronix II

SE Wis

I don't mean to be negative, but a few years ago, there was a forum member with a similar problem, and he sold his unit.  I acquired the set-up, and upon tear down, the manifold had a huge dirt dauber clod in one of the ports.  It was fuel washed and slick, so it had been run with the mud in the manifold.  It was nearly blocking one port, so there was no doubt that it affected the idle and running of the engine.  I ported the manifold, pressure washed it, and have run both the 94s and Strombergs on it with great success.  Also, one of the adjusting needles had been run in tight, and backed out, breaking off the tip and making that idle circuit inoperative.  I know this was supposed to be rebuilt carbs and built by an expert, but there are always little things that bite when you least expect it.  BTDT.  Joe-JDC

JDC