Probably. Could also be a timing chain problem.
Sounds like a head gasket problem. Better run a compression check.
First double check the timing. Plug wires not in the right place. Intake are exhaust valve problems. Bad distributor cap. Check these things first. If you don't find the problem in this area then please ask your question again.
it can be of all stupid things a improperly fasstened gas tank cap
exhaust
yes
Follow the path from the exhaust port on the head. That will show you which is the exhaust rocker, which leads to the exhaust pushrod, which leads to the exhaust tappet.
Check all the passageway it may be blocked with carbon and other exhaust dirt. the (EVP) may also be faulty (exhaust valve position sensor)
Exhaust manifold torque on 5.7 L Chevy is 25 ft/lbs using anti-seize lubricant.
You will need to remove the exhaust manifold retaining bolts in your 1993 Chevy Astro. Remove the exhaust manifold. Remove the exhaust manifold gasket and clean the surface. Reverse the process to install the new exhaust manifold gasket.
Exhaust leak at Exhaust manifold to head gasket or oring at exhaust manifold pipe.
headers may be to small meaning more air coming thru carb or efi than leaving the motor thru the exhaust. You have to think of a motor as a huge air compressor. Had same problem 10 years ago when putting a vette 350 into a Chevy pickup trying to us stock exhaust. Which if read article right this is not a stock exhaust. Glowing headers can be a symptom of a lean condition, vacuum leak, or timing problem (ignition and cam timing).
What kind of valve? Exhaust valve? EGR valve? PCV valve?