bbc head APPLICATION

**John** · #1 10-16-2007, 01:45 AM

I just picked up a set of Closed chamber big block square port heads.
One is dated D 13 70 ( casting #291 )
and one is dated H 24 70 ( casting # 840 )
..What would the application be for?
....1970 LS6...or 396/375 or both?

**WILMASBOYL78** · #2 10-16-2007, 03:00 AM

The 840 heads are the 68-69 closed chamber head for L78/L72 applications...the 291 is the 70 model year for LS6 and L78. I've never seen a 1970 dated 840 head...perhaps it is a service replacement part..??? I'm sure some of the part number gurus will know...so, what you gonna' build???

wilma

Unreal · #3 10-16-2007, 04:14 AM

291s were used on late 69 L-78/L-72. Seems like someone on this site talked about a car with 840 on one side, and 291 on the other.

**WILMASBOYL78** · #4 10-16-2007, 04:19 AM

It would be interesting to see if they both have the same style spark plugs...

wilma

**427.060** · #5 10-16-2007, 04:27 AM

I have a mis-matched set like this too but the dates are a lot farther apart.
James

**John** · #6 10-16-2007, 04:43 AM

I will get some photos of the plug area and the dates..but that is what I thought ..
...840's were 1967,68 & 69 ( not 70 )
thanks for the help

nuch_ss396 · #7 10-16-2007, 05:17 AM

John,

That '840 with the '70 date would be a service replacement
only - as others here have suggested. Regarding the spark
plug seats, it would be interesting to see if the '70 dated
head has a non-peanut style seat. One more application for
those heads was the L/71 ( so that's L/71, L/72, L/78 )

Nuch

**John** · #8 10-17-2007, 02:29 AM

Here is the photo of the 840 head that I thought was
dated H 24 70 ...or am I misreading it?
...or is it H 24 7

**John** · #9 10-17-2007, 02:31 AM

Here is the other side of the same head

**John** · #10 10-17-2007, 02:34 AM

here is the 291 head dated D 13 70

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.