Help finding CC of 440 cylinderheads

[christianlarsen]

Hi.

I need to calculate the compression ratio. I have all the number except the CC of my cylinderheads.
The engine is original 440 from 1970. I dont know the number on the heads but i know its the poorest ones i can have. I heard about 906 heads in iron and that NOT what i have but worse.
Can anyone deduct from above what CC i have ? If there f.x. only are a couple of other types could you tell me the CC of them because then i can calc a minimum or maximum.
Thnx
Christian

[EffinDuff]

http://www.mymopar.com/headcastnumb.htm
http://www.autohobbydigest.com/tables.php?03_Head-Casting-Numbers

From what i see they range from 73.5 to 83.1 depending on the casting number. More likely the 
Definately locate the casting numbers on the head and it will tell you exactly what you have.

The casting numbers for most RB, B, LA heads are found in two places. On the underside of the head on an intake runner, and under the valve cover on an intake runner.

[Nacho-RT74]

don't trust on those capacities. 452 heads states 81.5 AND REALLY IS AROUND 92 CC.... BIIIIIIIG difference when you are trying to built an engine combo based on specs given

[EffinDuff]

i have aftermarket alum heads so i never really looked hard for good #s.  Do you think its more of the site screwing the numbers up or just the mfg cheating numbers in their publications?

do you have a better source for these numbers?

[frederick]

It's the manufacturers:
By quoting 10:1 compression they could use that for their race cars and still be able to comply to the rules, while the street car had more like 8:1 and didn't have any pinking problems.
My 452's were 90,5cc by the way.

[John_Kunkel]

I've CC'd a bunch of 906 heads and they all ran in the 88-91 cc range. This drops the advertised compression ratio about half a point, so a '68-'69 engine with an advertised 10.1-1 would be more like 9.6-1 and a '70 from an advertised 9.7-1 to a true 9.2-1

[EffinDuff]

A newbie question but how do you measure the combustion chamber?

[Nacho-RT74]

My 452's were 90,5cc by the way.

I measured mines and got 92cc

EffinDuff...
http://www.merkurxr4ti.com/chambervolume.html

[John_Kunkel]

Here's a kit for measuring chambers or you can get a burette from a medical supply and make the rest yourself:

http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRO%2D66831&N=700+115&autoview=sku

[375instroke]

The generic numbers are 84cc for closed chamber and 88cc for open.  I got a burette from a local kids science learning supply store.  Other places wouldn't sell to me because they said they were used by drug labs.  WTF.  Idiots.  I paid $4 for the cheapest one.  No stopcock and only 50cc, but glass Pyrex, accurate, and .1cc resolution.  I used a clear CD from a CDR spool with white lithium grease to seal to the head.  Put the valves in and fill it up.  I filled the burette with paint thinner, put my finger on the top, drained it down to the 50cc mark, drained it into the hole in the CD, and filled up the burette again and drained to 50cc.  This time I filled up the chamber slowly till it was full and read how much was drained.  That plus the previous 50cc gave me the chamber.  Remember, only $4, or you can spend $50 plus shipping for a 100cc with stopcock.