Ok I have a 91 firebird with an 86 305 carb engine in, I just put on an edelbrock intake and Holley carb it was running fine, then it back fired so I rebuilt the carb and then it back firebird again but was running alright. So I am driving down the road and was hearing what sounds like detonation. So I am pulling into a friends house and put the clutch in and it stalled out and a cloud of oil smoke followed, but it was coming more from my engine compartment and not my exhaust and the detonation sound got worse as further I got down the road but I had to get to the friends house and I figured I only paid 50$ for the engine anyway it's not worth the tow well long story short it started rough in the morning but ran smooth til it got warm and the best way to describe the noise is that it sounded like a Diesel engine and I really need my car to get to and from school please respond ASAP. Thanks Chris

 

Did you check the timing correctly? Unhook the timing connector?
Check for loose rocker arms.
Check oil pressure.

 

My oil pressure gauge doesn't work but I tried playing with the timing but no luck. But I will check the rocker arms

 

So does it sound like a knock? I can see a rod knock sounding like a diesel.

 

It does kinda sound like a knock but uim not too sure if it is

 

Without a oil pressure reading ,all we can do is wishful thinking...........

 

compression test..
then a leak down test...

sounds like you hurt the engine "a cloud of oil smoke coming form the engine" is never a good sign.

 

Sounds like you blew out an intake gasket. Did you glue the gasket down first, before installing the intake? Did you let the sealant cure before your started the engine?

Just trying to figure out some background....

 

I actually just put a new intake on the engine and I used silicone around the water ports but it didn't have coolant ports on the back half of the intake. Is that uncommon? Did I get the wrong intake? And I let the silicone sit for 3 hours but no longer

 

So you didn't use anything else? I ALWAYS use Gasgasinch or an equivalent on the intake gaskets. I brush it on and install the gasket on the intake....using bolts n washers to hold it in place. Then I let it set up over night. I then install the new intake....using silicone or equivilant around water passages and front and back of intake......Gasgasinch on the rest. I install the intake, torque it down and let it cure overnight. Then I come out, re torque everything, thine fill with fluid. You probably slipped an intake gasket.

Don't worry about the rear crossover, it's not on most SBC intakes.

 

Can I get in this guessing game too??.