1984 Chevy 350 still being a headache to get running right

[Pig Predator]

Whats the oil pressure like? 10 lbs of oil pressure per 1000 rpm is minimal.

 

[grandall1972]

Carb jets?

this is possible, and one I’m planning to look at next.

 

[grandall1972]

Your vacuum is too low at idle, should be 18 to21 inches. I would look for a vacuum leak or restricted exhaust system. This truck should have the bead type catalytic converters, they are bad for stopping up and causing problems.

Looks like cats were removed when the engine was swapped and fuel exhaust added. I didn’t plug off any other ports when checking vacuum, but don’t believe I was loosing much anywhere else.

Thinking about checking valves next to see if they are adjusted correctly.

 

[grandall1972]

Too much fuel pressure for a carb. What kind of carb? Have you checked the throttle linkage for full throttle? Vacuum is low. What intake ? Why no engine picture ? We don't need a picture of the outside. Stuck EGR valve ? Vacuum leak sounds like an option. You need to help us. What is the actual camshaft ? Stock type is vague? Could it be a boat cam ? Is the cam worn out ? You say you checked the cam is the cam sprocket adjustable ? crack sprocket ? Look at the linked article. someone could have improperly installed and adjustable timing chain set. https://www.racingjunk.com/news/degreeing-a-camshaft-for-small-block-chevy/

pictures of the engine attached. Dont know the camshaft, but previous owner who put the engine in said used a stock cam shaft for a 350. No looe or anything. Just a smooth quiet 350. No egr valve, cam sprocket was aligned correctly and chain/sprockets looked new.

 

[grandall1972]

Might need to drop the exhaust to eliminate that.
The motor is pretty much stock right? Not radical as far as HP and cam shaft?

There is a shop in Chamblee.
J&L Auto Service.
Good folks that specialize in older cars. This would be right in their wheelhouse.

engine is set up as a stock engine. Nothing special.

 

[grandall1972]

Is the timing pointer correct for the engine? Are you sure it is a 350 ? You set the base timing with vacuum advance unplugged from the distributor?

It is a 350, timing marker is in the correct location. Timing was set with timing advance unplugged and and line stopped to prevent vacuum leak.

 

[Navy/ArmyVet]

Vacuum is too low for a stock engine. Check for possible leaks. You may have a bad fuel system. The tank may be contaminated or the sock filter in the tank could be restrictive or collapsed. Try running engine with an alternate fuel container. This could be a flexible line thru the top of a fuel can. You don't normally need more than 5 psi fuel pressure for carburetors. Too much will force fuel past the needle and seat resulting in a rich condition. Just a few ideas.

 

[grandall1972]

3 to 4 psi is all you should have on fuel pressure.

21" is what you should have on manifold vacuum with the engine warm.

Take the cat converter off temporarily to check for obstruction.

Edlebrock states 6psi I believe so still high. Thinking of trying a pressure regulator, but it’s also just running the stock mechanical fuel pump as well.

No converter on the truck. I need to warm it up and check vacuum again. 15 was at the bottom of the green and I didn’t check or block off every port to ensure no extra vacuum was lost.

 

[grandall1972]

Vacuum is too low for a stock engine. Check for possible leaks. You may have a bad fuel system. The tank may be contaminated or the sock filter in the tank could be restrictive or collapsed. Try running engine with an alternate fuel container. This could be a flexible line thru the top of a fuel can. You don't normally need more than 5 psi fuel pressure for carburetors. Too much will force fuel past the needle and seat resulting in a rich condition. Just a few ideas.

Will look for vacuum leaks but at 15 vs 18-21 which would be ideal I wouldn’t think I would have so little power.

Fuel system is new from the Tank to the carb.

 

[grandall1972]

Whats the oil pressure like? 10 lbs of oil pressure per 1000 rpm is minimal.

oil pressure is great.