Need Help! 1977 GMC Vandura- 5.7L 350

[bjohnsey]

Good Afternoon Everyone,

 

I am new to the forum and am having some issues getting my '77 Vandura back on the road. I have owned it for almost a dozen years and want to drive it again for camping etc.

 

A few years before I started driving it my old man had the original 305 switched to a 350. I drove it for years like that with little to no issues. Let it site for probably 8-9 years now and decided to get it rolling once again.

 

After tidying things up, checking oil levels and adding fuel surprisingly it fired right up. Got it back from my parents place to Calgary into my garage. While driving it around I was getting what sounded like a slight misfire and was bogging out when placing any load on the motor.

 

Replaced carburetor- 2 barrel rochester, spark plugs, fuel filter and fuel pump.

 

Road test: Running better still bogging out especially when going up hill.

 

Found leaking fuel line coming from gas tank. Replaced that.

 

Road Test 2: Ran nice for 10 miles, misfiring returns, engine begins cutting out at intermittent times. Increasing intervals the further I go. Turned it around and returned home.

 

Shut it off and let sit for a few hours.

 

Restarted now when I push the gas instead of a nice rumbling sound that I heard earlier it almost sounds like a bullfrog is in the carb. Almost like its sucking massive air through somewhere it shouldn't be. If I let idle the misfires get really bad and the engine begins to shake.

 

Please help me out as I am not sure what I could do short of replacing the motor.

 

Thanks in advance!

 

Brandon

[grampadirt]

How does the new fuel filter look? After sitting for so long there could be sentiment in the tank that was picked up.You could disconnect the fuel line at the carb,put the end in a suitable container and with a rag on hand have someone crank the engine over to see if adequate fuel is coming out.Be real careful though not to chance igniting the fuel,keep a fire extinguisher handy.We'll start there,more to come.

[Duelin]

Disconnect your EGR valve and see how it runs. Make sure you plug the vacuum line.

[barry G]

those vans compress the engine space..they ran a long time even with the hot 400.

try four barrel, spice it up some.. maybe an aftermarket coil or a whole hot rod kit from summit or jegs or wherever..

disty, the whole thing, coil, fat wires.

 

accel got some nice wires.