zz4 fast Burn 385 by pace

[orange RS SS]

I need help.I have two dead cylinders # 8 and #5. They are getting fire from distributor,both have 184 compression. I changed all spark plugs,rebuilt carb.The old plugs I pulled from #8 and # 5 were very clean burning very lean like a not getting fuel. All other plugs were burning rich black sutty.This engine has vortec heads and vortec 4 bolt intake manifold.I used a carb. plate to install engine and transmission. I have been told that this may warp intake manifold,causing a internal vacumn leak ,Which will cause a lean fuel mixture.Could this be my problem?:hammer:

[orange RS SS]

Anybody need help

[regal454]

I would check simple things first before you start digging into the motor. What color is the spark on those 2 plugs? Try swapping those 2 plug wires with known good cylinders and see if that helps.

[Mach Par]

I would check simple things first before you start digging into the motor. What color is the spark on those 2 plugs? Try swapping those 2 plug wires with known good cylinders and see if that helps.

I'd recommend check the distributor cap as well. If it's dirty or got some condensation it'll cause issues. I don't think using a carb plate would warp anything.

[badazz81z28]

Double check the firing order. Make sure the plug wires are in the right order.

[orange RS SS]

Double check the firing order. Make sure the plug wires are in the right order.

The two spark plugs are a lite tan color,all the rest are black sutty,I did swap plug wires,and install 8 new spark plugs,dist. ck out good too thanks for the info.

[MarkM66]

Is this the intake that came with the engine? Has it ever been removed?

SBC intake gaskets can be tricky sometimes.

[gak68]

Is it a flat tappet cam? Did you loose the lobes on the intake side?

[regal454]

That motor came with a hydraulic roller from GM.

[orange RS SS]

I may have found the problem. the vacumn booster, when I plug off vacumn to booster. the # 8 cylinder come a live. Its not dead like before. Had to order the booster ,2 days to come in. I will let you all know if this fixed it. thanks for the help