'69 Vette Casting Numbers

[Don W.]

I had the valve covers and carb off my recently purchased 69 427/390 hp THD and pulled some numbers off. I have Bizzoco's 69 Stingray Guidebook and I don't see anything that looks close. Any help is appreciated.

CARB
Rochester QuadraJet
Has a white sticker on the side with a bar code
970539
0180
Remanufactured By Holley
70* (7066) * = a number I can't read
casting number 29231 0209

PASSENGER SIDE HEAD
GM8T
J25.9
396290

DRIVER SIDE HEAD
GM 1OT
J28.8
3964290

[Jack H.]

Re: '69 Vette Casting Numbers

Looks to me like the carb is a rebuilt substitute and the '290 cylinder heads are from a 454 BB doner (those WERE the castings used in '1970)...

[Joe L.]

Re: '69 Vette Casting Numbers

Don------

I think that the carb number is likely 7027066. If so, the carb originally resided on (or, was SERVICE for) a 1967 Pontiac. This surprises me since I thought that Pontiacs used a "straight in" inlet style Q-Jet. I thought that only Chevrolet and Cadillac used the "90 degree" inlet style Q-Jet. However, it may be that some Pontiacs did use the "90 degree" inlet style. Anyway, Holley, apparently, used the Pontiac carb CORE to "build up" a re-built carb for your application.

As far as the heads go, if the passenger side head casting number actually is "396290", then I'd say it's some kind of foundry mistake. There never was a big block head of GM casting number 396290. If there had been such a casting number, it would not have been manufactured as early as 1968 or 1969. And, the number is "suspiciously similar" to the expected number of 3964290.

I believe that the 3964290 cylinder heads may have been used on late 1969's. So, if the car is a very late car, the heads are likely original. Also, I believe that the last digit of the casting date for BOTH heads is a "9". An "8" and a "9" are very often hard to distinguish with cast numerals. I don't think that you'd find any 3964290 head cast in 1968.

So, if I'm right, both heads would have been cast in vary late October, 1969. This would mean that any 1969 built originally using such heads would had to have been built in November or December, 1969. So, if your car "fits the bill" as having been built during November-December, 1969, then I'd say the heads are likely original to it.

[Mark #28455]

What size spark plugs does it have?

I agree with Joe that the 290 casting heads did appear in the late 1969 model production run. In addition, the 291 casting rectangular port heads also seemed to replace the 840 casting heads.

One question that remains is whether the heads were machined for the 13/16" gasketed type plugs or the 5/8" tapered seat plugs. I don't think anybody is really certain about the right answer, but I suspect the 5/8" plugs may have been introduced at the same time as the "1970" style head castings.

Please let me know which ones your heads used.

Thanks,
Mark

[Don W.]

Re: What size spark plugs does it have?

Thanks Jack and Joe,

The car is in the shop right now getting the carb rebuilt and some other work, I'll check the numbers with the shop on Monday. Yes, the vehicle is a late 69 build. The protecto plate has a date of 12/12/69 and build sequence from the VIN is 35418 out of 38762 built in 69. The engine code is for a Nov 6, 69 build

[Dick W.]

Re: What size spark plugs does it have?

I agree that the heads could have possibly been installed at Tonawanda. This will be added to the things to research for the manual revision

[Mark #28455]

Sept 69 and Feb 70 290 casting both have 5/8" plug

I have several 290 casting heads in my collection, the Sept 1969 and Feb 1970 both use the 5/8" tapered seat plugs. That's why I suspect that the change-over to the 5/8" plug occurred with the change-over to the new casting.

Mark

[Don W.]

Re: What size spark plugs does it have?

I rechecked the head numbers for my '69 vette 427/390HP. The protecto plate shows a date of 12/69. The head numbers are 3964290; this matches up with the '70 oval port heads for a 454. The date codes show J25 9 and J23 9 which equals Oct 23 and 24 1969; so I think that would match up for a car sold in December 1969. Maybe I have a one-of-kind.........Don

[Joe L.]

Re: What size spark plugs does it have?

Don-----

No, I think there are more than a few late 69's out there with the same heads. Did you check the heads to see what spark plugs it uses. Does it use gasketed spark plugs or tapered seat plugs? If you aren't familiar with the difference between these 2 types, does it use a 5/8" socket to remove the plugs or does it require a 13/16" socket to remove the plugs?

[Don W.]

Re: What size spark plugs does it have?

I'll check later this week and post a response.....Don