Oil pressure. check with a good gauge after replacing the oil and filter.
Check at the oil port by the distributor on the back of the block. (full oil pressure)
Eliminate the remote filter, oil cooler and retest. Could be blocked-restricted.
Thumpr cam. Could have used that in your vette w the 3000 stall and 4.11's.
These cams work well when the motor is set up correctly for them.
Compression ratio, torque converter and gears, head flow, distributor recurve or lock out.
Making something of what you got. What yu got is a low compression ratio engine wiht crappy heads.
The 882's are crappy even when ported. The only value in those low flow restrictive low compression heads is the 2.02 x 1.60 valves and studs and guide plates parts.
Could be used on the 920's with porting to build a low cr blower motor.
could be used in a small chamber high flow (new bare castings or ported 58 to 64cc heads) perf head.
Reguardless of how you use the other pats the crappy 882 heads will result in lame performance, no power no torque.
You hav a bad habit of buying what is offered instead of what you actually need.
The 4.10's with a 31" tire would be fine on a supercharged 350SBC in your car.
For a N/A -cammed, built 350 and 31" tires you want a 5.38:1 gear ratio.
If you are going to build a N/A motor the 4.10's are not enough gear.
Again buying a bunch of parts that don;t work together. and or have very poor power potential, just cause someone offered them. (882 heads)
You will end up spending twice as much and get half the performance.
The thumpr cams can both work well but you need to use them in a real motor (10;1 10.5:1 compresssion
and decent head flow) for them to make power. They need gears and converter and flow!.
They will not work n a low cr motor with crap head and no gear (4.10's and 31" tires equals no gear.)
Do not buy less than a 5.13:1 gear for a N/A motor in this car with a 31" tire.
If the motor is worn out or wounded, then do nothing. Wait, get your kid his braces and save your money.
Just drive it as is. save your money and plan a good motor combo.
STOP BUYING odd, cast off used-crappy parts just cause they are for sale.
You will end up with 1000's of $$$S wrapped up in junk.
You need to find another set of the 305HO 4416 heads or other small chamber 58-64cc head to work with the thumpr cams. in your stock 350.. Low cr will not work.