The article featured on this page is from the March 2011 issue of Auto Enthusiast Magazine.
Less Is More
Especially when it comes to heater and radio deletes
Story Wayne Scraba
Tucked away in the pages of early Chevrolet dealer albums and option lists was RPO C48. While most GM-philes are familiar with option C60, which was the standard air conditioning Regular Production Option in the muscle car era, C48 isn’t quite so common.
That’s because it signifies a heater delete system. Essentially, with this RPO, the factory left off the heater equipment and the buyer received a credit (which ranged anywhere from $30 and change to just under $100, depending upon the car). From a practical perspective, the heater delete system usually went into two different types of cars – those destined for extremely temperate climates and those destined for track duty.
Although the RPO shows up in some 1969 factory materials, few (if any) cars were likely ever built with the option since window defrost systems were government mandated a year before. Nonetheless, you’ll sometimes stumble across muscle cars (and even some not-so-muscle bound examples) from 1969 and earlier with heater delete systems. And this includes not only Chevrolets, but other brands as well. Typically, when a heater was deleted, that meant the complete heater box assembly was gone (on both the engine compartment and passenger compartment sides).
The ducting for the defroster wasn’t installed and the dash mounted controls weren’t included. Ditto, of course, for heater hoses and various water pump/intake manifold fittings. In place of all of these parts was a plate or a set of plates for the engine compartment along with another plate for the instrument panel. Believe it or not, the defrost duct openings in the dash top were (in the case of Chevys) simply taped over with basic covers from the backside (see the accompanying images taken from a 1969 Camaro Assembly Instruction Manual or “AIM”). Coolant fitting ports on the intake manifold and water pump were either plugged or capped off.
Obviously, if you lived in (for example), Hawaii or Guam and you had no need for a heater in your vintage Camaro, then the $30 or so you received as a credit was good news (keeping in mind something like a ’67 Camaro sport coupe had a base price of approximately $2,500, so the discount percentage was reasonable back then). But from a racing perspective, the weight savings were important – one could easily carve at least 15 to 20 pounds off a car with the systems).
Although the actual heater assembly might not sound that heavy, think about the accessory components used to support the heater: hoses, clamps, controls, ducts, and the coolant that flows through the system. The weight reduction from removing the heater and accessory components will probably exceed the 20-pound figure. Likely more critical was the simplicity factor. Given both a radio delete (more below) and a heater delete, under dash wiring was a whole bunch more accessible. On the engine compartment side, it meant engine bits were easier to work on too. And even more important, the lack of a heater speeded up access when swapping engines. That was important when time was a factor.
Radio delete systems were different than heater deletes, and the process was less involved. For most cars, in order to delete the radio, you simply didn’t order one. That meant the hole in the dash was blocked off, no antenna hole was punched in a fender and the engine had no radio interference ground straps.
There were definitely different approaches to radio delete systems. Case-in-point is the late build 1969 Nova that takes up residence in the writer’s garage. That particular car is an unmolested, documented radio delete car. There are no radio ground straps installed on the firewall (but holes were punched for them), the antenna hole isn’t punched in the fender and the dash has a plastic plate covering the radio receiver hole.
Several years ago, we had a 1971 Nova that was also a radio delete car. In that example though, someone had in the past chopped up the dash cluster for an aftermarket radio. To replace it, we scored another cluster from eBay. That cluster was a one-piece job and never molded to accept a radio. Many years ago, we also owned a very late production 1969 Camaro with a radio delete. That car used a bolt-on radio delete plate. We suspect there was a changeover somewhere in time where Chevy switched from dedicated no-radio clusters to simply blocking off the cluster with a plastic plate (or vice versa).
Two decades ago, we paid $1,500 for a pair of beat up original heater delete plates for a vintage Camaro project. The dash plate was supposed to be included, but the seller somehow forgot. We never received it. A radio delete plate was built of unobtanium (if memory serves us correctly, we paid close to $500 for a vintage wood grain Camaro delete plate). Today, you can find brand new delete plates (heater and radio) for a plethora of applications.
1 Set of engine compartment delete plates for first generation Camaros. They also happen to fit third-gen (1968-1974) Novas. As pointed out in the text, in the past we had a set of original GM engine compartment delete plates. These reproductions are exact duplicates (except these don’t require a colossal amount of body work).
2A & B Here’s the plastic heater control delete plate for the dash.
3A & B The cluster is out of our Nova, so we took the opportunity to show you how the heater delete plate is attached. It uses the same hardware as the factory heater controls. The second photo shows a close up of how the original radio delete plate was mounted.
4 This is a look at the front (face) side of the cluster with both the heater and radio delete plates installed. As you can well imagine, eliminating both the radio and the heater makes the space under the dash positively spartan. That’s why racers love delete systems.
5 On the firewall side, the flange originally punched in the firewall for the heater core will often have to be bent slightly to clear the delete plate. A couple of additional holes will have to be drilled (in factory terms, “pierced”). It’s spelled out in the factory Assembly Manuals.
6A & B It’s no big secret that behind the firewall (passenger compartment side), a jute backed insulator pad was installed on cars such as the Nova and Camaro. If you look closely at this reproduction pad you’ll see that the heater opening is punched out, but included. To install it on heater delete cars, you simply apply a bit of adhesive to the backside (between the pad and the delete plate). Keep in mind the balance of the pad is attached with a series of push-in plastic fasteners, which are also included.
7A, B & C Chevy laid out the installation of the heater deletes in both 1969 Nova (7A) and 1969 Camaro (7B and 7C) Assembly Instruction Manuals. If you look closely, you’ll see where a simple black cover was taped from the backside of the dash to block off the defroster ducts in the dash. Black tape was also used to cover up the square heater hose clamp hole in the passenger side inner fender as well as on a couple of locations on the firewall. Things were certainly a bunch simpler then!
Chevelle Radio Delete Panels
Chevelle Firewall Heater Delete Panel
Camaro Firewall Heater Delete Panel
Camaro Radio Bezels and Delete Panels