Probably a casting set-up error. The "8s" should have been "9s". Is you car a late '68 build or a '69? No QA ISO 9000 back then. Stamping and printing errors in coins, bills and stamps are worth a lot. Maybe in intake manifolds too.
Early '68s used a 9790140 intake manifold. Late '68s used the 9794234.
It sure is weird. I cant find anything on 8784234....everything indicates 979 like you say. She was built early in 68 though...i have the original invoice and build sheets... April-May 1968. There are casting numbers on the block that have julians that if I read them right seem to agree with the purchase date. I'm puzzled by the 878 though....
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.
The production year for the '68s was about 8/67 to 6/68 so yours could be considered a later '68 build.
The "The Definitive Firebird & Trans Am Guide 1967-1969" by Rocky Rotella has a section about the '68 intake manifolds. It mentions, "The earliest date for the 9794234 manifold has been March 25, 1968 (C258)". It goes on the imply that that date may be the earliest 9794234 found. Rotella says that the drawings for the 9794234 indicate that it was designed in Feb. 1968.
Does it mention an 8784234 in the book anywhere? Do I understand then, assuming the 878 was intentional, if mine was cast on March 14 they were using 8784234 until 11 days later when (theoretically) they switched to stamping 979.. So I could have the new 979 casting mis-stamped, or the last of the 878's? Doesnt matter really, other than would make another cool page in the story of this bird...
I'll have to find that book...
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.
Where's the date code on this manifold? I only see a "GM1" and the firing order stamp... That code C148 is on the block next to the distributor port. This is the only other decent pic of the intake.... I'll need to look around on it...
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.
Very bad shape casting, but looks like it might be C2 "?" 8... maybe a "1" so March 21, 1968?
But I got I real close last night and I think I'm wrong... starting to look more like a typical 9794234, not 878... Hope I didn't waste anyone's time...
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.
Thx Bart- I confess the picture is from a while back. It was just a good view of the number. A lot has changed since then, including a new spring! But thx for looking out for me!
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.