Just taken the head of my X-flow 711M…..BA and was surprised to find that the head was not flat but has shallow combustion chambers. At the time I bought it (20 years ago) I was told it came from a mk2 Cortina E – would this be correct. The pistons are bowled but don’t have recesses for the valves. It also has a 32dfm Weber and C7BH C distributor – if this helps.

Welcome to the site

As far as I know, the 711 blocks were only ever fitted with flat heads, the 681 blocks having the bowled heads. Although I think all had bowled pistons. Certainly the block is not from an original Mk2 (if 'BA' is stamped on there, it's from 1981), but the inards could still be earlier, the head certainly is.

Hope that helps,
Bill.

711m BA is a 1600 and 711m AA is 1100 or 1300. I'm not sure but think pre 1971 engines had chambered heads.

Got me searching. Heres a link to some info Linky

[Edited on 23/4/07 by TGR-ECOSSE]

Early 1.6 cortina's did have shallow combustion chambers, you need to pension this head off as they were not very good.

This is strange of course because flat heads are generally inferior, but there you go.

Regards Mark

Perhaps not 100% true, seriously modified heads (or ones that have been skimmed a lot) can have small combustion chambers machined into them. I almost bought one, didn't know this and thought it was an early head. Considering the price i was about to pay I missed out on a damned good deal

I've just typed out a long reply to this topic and then deleted it like an idiot.

I will try again.

The reason why high performance Crossflows have chambered heads is to do with piston weights. If the combustion chamber is in the piston (as in a post '70 Crossflow) then the piston needs to have a very thick and consequently heavy crown. This reduces the revolutions of the engine. Having the combustion chamber in the head allows for much lighter pistons and connecting rods which allows for higher revolutions. More revs means more power. Early Crossflows (the 691 Crossflows) had Heron pistons and a slight chamber in the head and weaker main bearing caps and are no better for tuning.

MikeR. You might have got an expensive head for cheap, but you will need an expensive bottom end to go with it. Memphis twin on here taught me that one when he gave me a steel crank for a 1300 crossflow.....

there are conflicting stories about which is the better of the two heads; now according to wallace, there is a thrid type of head - this has a combustion chamber machined in whcih is not the same as the FORD OEM head whcih is the one that has the best performance.

Thanks for the welcome, link and all the responses.

Given my head does not have large valves or guides would make it a pre Oct 1970 head right and given the early pistons and block that’s post, could it be the result of an October 1970 factory build emptying their bins?

Since an upgrade doesn’t look like it can stop at the head I may have to leave it as it is. Unfortunately the car has to go as I need the garage space and being a Dutton is going to limit its value and therefore anything more than a head may not stack up.