My 74 Nova just started backfiring, it also will not accelerate past 25 mph , this just started happening out of no where, was running great before this. Backfires occur while in park , and if you give it some gas. When in drive at about 25 mph the engine makes a gurgling noise and starts to shake.

Blown Head gasket , bad carb ? Any suggestions for this novice would be appreciated.

Engine is a 350 ci 8 cyl , 4 barrel holly carb , 350 turbo tranny / BM shift kit.

How many miles on this motor? It sounds like a timing issue check your distributor maybe the cap has a crack, if it has a lot of miles might just need service cap, rotor if all checks out maybe your timing chain has jumped a tooth I could be wrong but that's happened before:yes:

That's exactly what it sounds like to me is a jumped timing chain if it just started happening suddenly like this. I agree check the rotor and the cap first, may get lucky and only have a cracked distributor cap or rotor. But if they are good then you'll need to start looking at Cam timing and distributor position.

The engine is rebuilt, with about 25,000 on it , thanks for the tips, i'll check on those and get back with my results.

line up the mark on the dampner at TDC with #1 on the rotor... then rotate engine opposite way, line up the mark again and see how far off the rotor is to #1... if it did jump a tooth the rotor will be quite a ways off ;)

Have you piched the EGR valve? It might be sticking open/closed and killing your performance?

Being a 74, does it still have point ignition or have you changed to HEI?

Being a 74, does it still have point ignition or have you changed to HEI?


It has an upgrade, Mallory ignition system ( promaster coil, and unilite ignition )

lets check things in order.

The ignition system.
Cap, wires

Fuel system, getting fuel? (Is fuel contaminated? Water?)

Check timing with a light.

if all this is OK.
We move to next step.

Compression check.
Radiator pressure test.

Al

you said you rebuilt it and up graded the ignition, another simple thing to check is the distributer it's self pull it and see if the gear is worn or if anything is loose under the cap. the water in the gas is a good call too

First off , thanks for all the tips and advice. I think its quite possible that there was water in my distributor. I did not drive the car for a few days, and when I went back to it , it was running better, but still a bit rough.

So far I have changed the spark plugs , which were in rough shape, filled the tank with premium fuel because it was also pinging. I drained and refilled the radiator since it had been a while.

Now it is running much better, the distributor cap and rotor will be my next project when I have time for it.