3877660 Thermostat Housing

[Kevin Whiteley]

I examined the archives regarding the 3877660 thermostat housing, and I'm still confused. The one I have is flaking off orange paint. Most of the paint is gone off of the spherical portion of the housing. Right where the dome meets the spout is "GM 3877660" extending up the spout. Anything else is covered with the hose. My 68-69 Judging Guide says that the dome should have an alpha-numeric code stamped into it. Mine doesn't. Mine does have the two recesses near the short flange and one recess near the tall flange. With the exception of the Judging Guide, I believe it to be a production part, not service or reproduction. Any other ways to tell?

Also, even though the housing is currently on a SB, is this the correct housing for a 68 L71 BB?

[Gerard F.]

Re: 3877660 Thermostat Housing

Kevin,

I have the same part number original to 1967 327.It's cast aluminum. However the part number is on the flange, and not in the location you indicate. I'm not a '68 guy, and maybe they changed the part number location for 68. I know that Paragon puts out a reproduction with the number in the location you specify.

Maybe one of the '68 guys will chime in on this.

Jerry Fuccillo
#42179

[Mark #28455]

Re: 3877660 Thermostat Housing

In the earlier cars, the part number was on the flange. My 1969's are as you described yours to be. In 1969, the aluminum housing was used for all motors except the L88.

[Kevin Whiteley]

Re: 3877660 Thermostat Housing

Thanks Mark and Jerry,

However, what's the definition of "earlier"? and did all come with the throttle return spring flang? Finally, any reason the Judging Guide says there was a code on top of the dome and mine doesn't?

[John H.]

Re: 3877660 Thermostat Housing

The GM part drawing, released 2/1/65, shows the part number location as "optional", and there were at least three suppliers for the part, but apparently the only one that gets full credit is the one from the supplier that put the part number on the flange (at least on midyears).

[John L.]

Re: 3877660 Thermostat Housing

Sounds like a JM revision may be in order.

[Peter L.]

Re: 3877660 Thermostat Housing

Kevin - Be sure to check the Archives if you haven't aready. We've all gone round and round on this one. The bottomlne is some say it should be on the base, some say on the neck, and some say there were two or more suppliers so either configuration is acceptable. My read is we really don't seem to know exactly what happened when the General put the thermostat housings on these engines, so if you think the one you have is original to the car and you're into originality and what's right, stick to your guns; if you need the points, it's your call. Pete