Hello, I was hoping someone could help me with a issue me and a friend are having. My friend recently purchased a '80 Chevy 3/4 ton 4x4. It has a 400 small block with a 4-speed tranny. It was used as a mudding rig till the guy who had it was running it and it backfired and caught fire, it didn't damage much, just throttle linkage and filter. But we pulled the 4-barrel holley carb off to rebuild it and there was antifreeze in the carb. I don't know how it could've gotten in the bowls, and it is a double pumper and there was some antifreeze in both bowls, and we don't have any idea how it could've gotten there. Maybe someone put some in the tank on accident, or could it be an engine problem? Thanks to anyone who have any suggestions.

If there is none in the gas tank, the only other point of entry would be through the bowl vent tubes. I have seen a 400 small block that blew the head gasket between the cylinders, "coughing" antifreeze back up through the carburetor. I can't recall if any got into the carburetor bowls, but with the vent tubes in the same air stream, anything is possible. I would check your gas tank first. Remove the fuel line from the dual feed line, with the power to the distributor disconnected, have someone crank the engine while you catch the gas being pumped into a cup. If you see beads of antifreeze in the cup, it's in your tank. Good Luck.

Thank you Diesel Day Dreamin, we tried that and the gas looked clean, so I guess we will be pulling off the heads to check for bad head gaskets, thanks for the reply. I will prolly pull the heads while he rebuilds the carb, (I'll take the easy one, LOL) to see if we can get it running properly. I know before this problem the truck was VERY powerful, so hopefully we can get it running like it should.

Diesel_Day_Dreamin' Flawless response!!!

Well, Thank you... Sometimes experience is the best teacher. In other words, been there, done that!

400's have a few weak spots in the head gaskets due to the larger cyl bore. If you pull heads make sure you check them with a straight edge. Also during teardown check intake gaskets well, if they had a bit of leak, the motor "sneezing" could have pushed some coolant into carb

oh yeah... sure way to tell if it's a "true" 400 is there are steam holes in block and heads, between cyl bores