News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

322 vs 346

Started by rdsykora, May 25, 2014, 07:49:18 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

rdsykora

I was told that one of the differences between the 322 Lasalle motor and the 346 Cadillac motor is the the heads.  Apparently they are bolt on swap, but the 346 heads on a 322 have less compression
rdsykora

markl

Robert,
Yes that is the case.  I can't tell you off the top of my head what the loss would be, but that is the direction that things go when 346 heads are placed on a stock 322.

One word of caution; It is very common that when a 322 (LaSalle) is rebuilt, it is simple bored out to Cadillac standard, 3-1/2" diameter.  So if you have the heads off, check the piston diameter.  The difference is great enough that you can see it w/ just a ruler.

BTW, this post should really be in Technical and Authenticity, and probably one of the moderators will probably move it at some point.

Mark Lowery, CLC#25216

Tom Boehm

Hello, I have a 1940 Lasalle. It is my understanding that the heads for a Lasalle are the same used by a 75 series Cadillac. Yes, I looked it up in the parts book. The  '39 Lasalle, '39 75 series Cadillac, '40 Lasalle, '40 72 and 75 series Cadillac all use the same heads. The Lasalle heads on a 346 engine make a higher compression ratio, which is where the extra 5 horsepower comes from that the 75 and 72 have over the 60 and 62. The heads on my Lasalle are marked as such.

ebuliavac

Hi Tom,

I know this is an old post. Where do you find the markings on your LaSalle heads? I happen to have a set myself and I am trying to figure out what to do with them.

Thanks in advance,

Ed Buliavac
1940 6227C
1996 Fleetwood Brougham

Fred Pennington 25635

The compression ratios are stamped on one of the raised ribs on the head.
The compression ratio difference comes from the additional bore diameter using more of the quenched portion of the head.
Fred Pennington, CLC 25635
1940, LaSalle 5019
1940 LaSalle 5019 parts car
1968 Ford Bronco
1973 Mustang Convertible
2012 Shelby GT500

Brad Ipsen CLC #737

It is really hard to see the markings on the head.  I believe it is near the middle and on one of the machined flat ribs.  The last one I saw was marked 346.
Brad Ipsen
1940 Cadillac 60S
1938 Cadillac 9039
1940 Cadillac 6267
1940 LaSalle 5227
1949 Cadillac 6237X
1940 Cadillac 60S Limo

ebuliavac

That is interesting thank you both. Ed
1940 6227C
1996 Fleetwood Brougham

Tom Boehm

On my 1940 Lasalle the heads are stamped on the center two rib sections on the upper rib, right under the spark plugs. One section has "322-6.25" stamped and the other section has "346-6.70" stamped. The same heads are used on the Lasalle and the series 72 and 75 in 1940. The series 62 and 60S used a different head stamped "346-6.25".

LaSalle5019

I'll add another comment to this discussion....the head gaskets sold today are all made for a 346 bore so, using them on a 322 slightly lowers compression ratio. I recall seeing different part numbers in the parts manual between 322 and 346 head gaskets which would indicate that the 322 gaskets accommodated for the smaller bore back in the day.
Scott