how do you know what motor you have by numbers and which numbers are relavant ?

Asked by Apr 12, 2017 at 08:54 PM about the 1984 Oldsmobile Cutlass Supreme

Question type: Maintenance & Repair

we have a 79 GMC van and was told the engine is an 84 cutlass not sure what size it is a V8 what numbers or other identifying points could we look at to find out exactly what engine it is ? thanks in advance ;)

15 Answers


You find the casting number. Look for the casting number on the back of the block on the flat behind the head. Here is a sight to look up your casting number to find out what you have...

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can you send a few picture from uner the hood of the engine???? also there is a sticker under the hood on hood/radiator support/inner fender that will tell you what was in it when built...............or.........[Chart showing break down of 1973 - 1978 Chevy Truck VIN#'s.] From 1973 - 1980 Chevy trucks had a 13 digit VIN#. From 1981 - 1987 Chevy Trucks used a 17 digit VIN#. If your 1973 - 1987 body style has a VIN# located on the dashboard, with 17 digits, then it is between 1981 and 1987 model. If your truck has the VIN# on the dash, but it is not 17 digits, then it is a 1979 or 1981 model. From 1973 - 1978 Chevy Trucks had the VIN# on a plate, mounted to the driver's door jamb. Your VIN# can also be found on the factory options decal, located in the glove box. The decal lists all the RPO's (Regular Production Options) your truck came from the factory equipped with. If the 4th digit of your VIN # is a 4, then your truck is a "Heavy Half" ton, also known as a "Big 10".

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ps the above picture code will be in/on the front drivers side bottom of windshield *** hi Rowefast..if indeed the engine is an 84 one thing..if still a chevy motor easy to look at tab next to behind the left water pump runner....


I seen that picture too, hey Kelly.

ok the block # 14010203 then a little further along GM 5.0LG the intake manifold 14057055 how do these numbers tell us what the motor is ?

any word on making these things get better fuel mileage ?

indeed it's a 305 Chevy 2bolt the carbeurator option i guess it's a rochester carb a couple lines are plugged one big line is just open prolly for the air filter you suggest a Dual Jet/ Quadrajet ? and is that not what i have a 4 barrel ? and how do i know what tranny i have ;) the vin # says the van originally had a 350. thanks for your input

yes it is a 4bbl, what is ATM PostScriptia ? lol likes the quadrajets

lol so i have the quadrajet what can be done to get better mileage ?


Soooo, CLH8, you have a Chevy 305 2 bolt main engine with a Quadrajet 4bbl carburetor going on. The 305 engine was made for gas mileage for passenger cars mainly, just a step up from the 283 engine. But they had the Rochester 2bbl carb on them. Back in the day in a 1975 Mote Carlo I was getting 18-19 mpg. out on the highway with this. When ever that Quadrajet was put on an engine gas mileage usually would drop. But as TrannyMan was saying, the key with that carb is to find someone who has all kinds of these for parts, a good Quadrajet carb re-builder. The key with these is with the metering rods and the jets, to get the right ones into the carb set-up. Then keeping your foot off of the gas pedal you could improve gas mileage considerably. I did this with a 1976 GMC with a 350 engine, my buddy was the carb guy and had a crap load of Quadrajets. So where you stand with what you have keep the tires aired up, the engine tuned to the "T" and a clean air filter. On the trany, look for the gasket that matches this picture...

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thank you ATM, your sure are into this stuff i c ;) i will check the tranny and i did talk to a performance shop and he said AC sucks and i need to buy cap, rotor, coil, and wires but i could tell he was just trying to make sale talking fast too. i bought AC plugs and installed them and a new Fram Filter, and found out that the air cleaner on it is from a smaller engine most likely the 6cyl as the air filter was the right size. anyway will that matter ? and i also found something called the "Gadget man Groove" ever heard of that ? peace be with you

so the tranny is the TH350 and i can't seem to find the number for the carb i can see that it is a Rochester Quadrajet GM but we already knew that, so i assume the number is hiding somewhere i can't see which is the front passengers side ? but the diagram shows the Drivers side is where the number should be ? Tire size is rear 15" 31x10.50, front 15" 235/75 The rear end pot has 10 bolts but not sure of the gear ratio ? Happy Easter ATM

so the carb numbers are on the outside at the rear, i looked there from inside the van and there are no numbers just a GM stamp on the Left, a Made in USA stamp on the Right, and a Table Stamp in the middle that has A to N Vertically with 3 boxes next to each Letter whereby there are 3 punch marks on both the A and B, then 2 punch marks on the C and no other punch marks. Now on the Drivers side of the carb the stamp is Rochester Quadrajet. and it is very clean so no need for cleaning... the only part of the carb i cannot see is the front passengers side near the front !

today i put the right hose onto the Vacuum advance and it sounds better the choke is electric and does not work as there is no wire to hook to it, those numbers are not at the rear of the carb i will take a pic tomorrow, i was going to set the idle mixture with my flat head screw driver but the screws are not a slot there are just a rectangle end on the screw is there a special tool for the adjustment ? also i assume the EGR valve mounted on the intake look like a bigger diaphram that does not have anything hooked to it ? any idea where it should be hooked ? thanks ATM blessings

will the EGR help with fuel mileage ? any ported vacuum can go to the EGR ? as for the refueling and recharge try this : this guy Markus and his girl Cara are indeed a blessing to all life. they have all the recipes to fully recharge any human body ! peace be still

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