Vinyl roofs can also cause windshield pillar rust. While repairable, it may be more sensible to consider a different car if the rust is bad. A true SS model is worth grafting new pillars on. You should check the metal part of the dash board carefully as well. Rust tends to form in the corners of the windshield. Visible, flaking rust usually winds up requiring patch panels at the very least and the windshield has to come out to do it right. While we're on the subject, checking the entire windshield frame on a convertible is important as the header bar is a cap concealing metal underneath. If you see bumps and lumps under the header panel of a convertible, take time to unscrew the stainless steel trim and look under it. Some cars don't have a stainless steel cap, instead it'll be black or coated metal. Severe rust in this area is structural damage and will cost plenty to repair. It will eliminate most non SS cars for restoration due to expenses.
An SS convertible is worth saving from A-pillar rust but you'd be wise to seek another car if it's just an ordinary Malibu.
Documenting a Chevelle is more work than a Mopar or Pontiac. In an ideal world, you'd find a car with the original sales contract and Protect-0-Plate still with the vehicle and a build sheet tucked away in the back seat. During the 1968-1971 era, the SS was a separate series and had its own interior. The dashboard had gauges instead of a strip speedometer and warning lights and SS badging on the door panels. Many cars have been swapped over using Monte Carlo dashboards so don't rely on this alone. Most cars won't have these primary documents of authenticity. If the car has been through a lot of owners, you'll have to check the drive train and cowl tag for matching numbers. Starting in 1969, partial VINs were recorded on the engine and transmissions of GM cars for police usage in theft recovery programs. Even a few 1968 cars have partial VINs on both units. The body was stamped as well. With the engine block, look for a machined pad below the passenger side cylinder head near the water pump. A stamped letter/number combination reveals the engine plant, date of assembly and a suffix code indicating intended usage of that engine. A six digit partial VIN will appear on the same pad near the engine assembly date. At the rear of the block beside the distributor access hole will be a cast two digit year code and day/month casting. This gives you the year, month and date the block was actually cast. Machining and final usage assembly occurred later and is marked on the front pad.
True SS cars had the performance gauges and SS door badges but don't rely on them for identification. It's easy to swap a Monte Carlo gauge set and door panels are reproduced.
The TH400 transmission has a metal tag code which listed the application and underneath a stamping indicating date of assembly. A partial VIN appears on the oil pan rail on driver side of transmission case. The Muncie four speed has a partial VIN stamped vertically on the gear case on the right side of the transmission. Sometimes the VIN is on the rear driveshaft case right along the parting edge between gear case and rear driveshaft housing. If you have one of the rare heavy-duty three speed transmissions, the partial VIN is on a raised pad at the top of the case.-
The body can be confirmed by checking for a partial VIN stamping on the firewall under the heater blower motor housing. A quick and dirty check for in the field use is pulling the cowl shield grating out and inspecting the underside of the metal dashboard area for tampered with rivet mounts where the VIN tag is. Useful for 1970 and later cars only. A 1968 serial number is on the inside of the driver door A-pillar. The rear axle has no partial VIN but it can be checked for proper usage code and gear ratio. On some models like an LS-6 454, it helps confirm authenticity because certain pieces have to be present. 12-bolt Chevrolet built rear axles with upper and lower control arms were used on that model only.
Starting in 1972, Chevelle SS was no longer a separate model and could be ordered with a 350 small block if desired. Fortunately, 1972 was the year you could check what engine the car had by using the VIN. The fifth digit gave you the engine displacement code. Prior to 1972, the cowl tag only told you if the body was coded as a Malibu 6 or 8 cylinder and the VIN told you nothing about the engine. Another sign of big block option was the use of frame stiffeners in the front frame horns. Sadly, these and many other parts are readily available as reproduction pieces. Barring original documentation, your only line of defence from fraud is complete chassis and drive train inspection.
Speaking of which, there is a serial number on the frame of Chevelles. This number appears in a couple of places depending on the year but most often they're located on the driver side rail on the top just beneath the door or on the rear frame rail stamped on top or on the side facing the quarter panel. A dental mirror and some degreaser is necessary to see them. Most often you'll have no luck reading them unless the frame cleans up very well. This number is most often documented during restorations with a photograph. Following the guide will help you pick the Super Sport from a Super Swindle.