Motor turns no start have spark motor acks like it has way too much back pressure can smell gas on dipstick went to check timing marks and there are 2 on the balancer witch one do I use

 

Lot's of issues here.

A couple of questions. What engine is in your Blazer? (VIN W or VIN Z that distinguishes the TBI from the CPI injection)
What has caused the non-start condition?
What has been changed on the engine?

WARNING: Fuel in the engine oil means a lot of fuel has already run down the cylinder walls and diluted the oil. Change it before any further start attempt including filter and prime engine with a good 2 quarts, then change again and fill to spec.

How did you diagnose too much backpressure? What are the symtomps that make you believe that is a problem?

The pulley on the 94's should have but one mark which is at 0° BTDC. The correct adjustment is found on the emissions label on the radiator support.
To adjust the OEM ignition it is required to disconnect the connector (tan with black stripe) wire under the carpet in the passengers foot rest just below the dash.

 

It is possible that the motor was swapped sometime in the last 26 years with one from a late-95 that had the newer EDI ignition system which would explain the two timing marks. If that is the case, I'm going to assume CPI which would also explain the fuel in the oil if the 'nut kit' or fuel pressure regulator were leaking in the plenum (common problem on the CPI engines).

Your truck likely is not equipped with the EDI ignition system, but to get the crank aligned properly, follow the steps in the following thread --> EDI Engine Timing.

As far as the 'nut kit' or FPR is concerned, there are numerous threads discussing these items, but here is an old tech article with some pictures that should get you going --> Fuel pressure regulator on Blazer 4.3L CPI W engine by kerander.

 

There are 2 timing marks changed regulator it's a w motor old style cap and rotor changed cap and rotor it started ran it for just a little bit then shut off to put belt back on and then wouldn't start checked all pulleys all free