Quadrajet- How much warp is warped?

[greenweenie]

Time to rebuild my 1968 Quadrajet (7028212) before bolting it on my rebuilt 327. After getting it all cleaned up, I thought I better check for warpage since the QJ are well known for this problem. I’m just not sure how much out of perfectly flat is acceptable.

I checked the pieces using a metal straight edge and a feeler gauge with the following results:

*The air horn (top) had a dip in the middle when I checked it side to side near the front part of the carb. It was about .015 low which I didn’t think was too bad. It indicated no warpage front to back in the center of the piece.

*I set the air horn on to the main body without a gasket and found a gap on the passenger side of the carb at .015 while the driver side was tight.

*The top of the body (float bowl) was almost perfect near the back of the carb while checking side to side, but .020 low in the front when checking front to back.

*The bottom throttle plate (throttle body) was very flat and in good shape.

I got the new primary shaft bushings installed today and used J-B Weld TankWeld High Strength Automotive Epoxy on the well plugs.

The new air horn gasket is .050 thick so I’m thinking since the variation from flat is well less than the gasket I’ll be OK moving forward with the rebuild. I’ve heard that if the warpage is less than half of the gasket thickness, there shouldn’t be a problem. FYI, very nice kit available from Quadrajet Power online.

Any comments or experiences regarding warpage on your QJ would be appreciated. Also, has anyone had any luck spraying the gaskets with silicon lubricant to soften them up before assembly?