dilemma ...bought a 72 riviera,turns out to be a gs stage one car according to the trim tag. was buying it to make a full custom out of it. checked the engine numbers and the block does not match the vin,checked between the 7/8 plugs and no "w". going to check tomorrow if it still has the stage one heads,it does have the edelbrock alluminum intake,chrome air lid etc. was curious being the engine is not correct how sought after would this car be with docs from sloan. i also own a 72 x car that i still havmet finished the resto on and im not doing a resto on this riv,but i allso dont want to make a custom out of it if its worth selling sans the oe engine being gone...the x cars i know are sought after and bring some cash..wasnt sure on a riv? just curious on some feedback before i start looking at another riv to do..thanks.
There was no stage 1 option available on any riviera. You can order a Riviera GS, which came with big valve heads, but it would not have been advertised or decoded as a stage 1/GS in the trim tag. I believe GS rivs should have a WA engine code, or WF if standard Riviera. Does the Riv has GS badges on the fender?
To answer the OPs question on how sought after a 72 GS Riv is worth without the original engine. I am assuming its a GS since you state it should have the W engine. Value would be maybe 5%-10% more than a non-GS all other things being equal. The 3.42 axle would be what makes it have any additional value.