what head is better

Hi
Im building a 200 for my XM. I have two heads here, a ARC9DE 6049A and a 72BA 6049AA.
From what I have read the first is a 221 head and the 2nd is a 250 head. Whats the better head, I would imagine the 250 to have bigger valves? than the 221, but I have read the 250 is rather asthmatic. I plan to mill the head and intake to fit a 2 barrell as per classic inlines site.
I would rather use the 250 head as it already has valves fitted but will use the other if it will be better
Any advice appreciated :help:
thanks
ben

All have same valve size, even 250-2v head. the only difference is the combustion chamber size, earlier c9 head will be smaller than the later head, if your sticking it on a 200, use the earlier head, even that will probably have lower cr than your 200, but that might help anyway if your going unleaded fuel.
Remember that none of those heads have hard valve seats for unleaded.
What is your 200 head like? it should have the smaller 38mm intake valves and smaller log.
A7M

Thanks for that. I dont have a 200 head, these are what Ive ended up with from various trades. I havent measured chamber volume yet. I plan to machine some off to up the CR a bit, but reading what youve said, the 221 will be closer as a starting point. thanks

before skimming the head set up the squish (quench) on the block

when you get the new pistons in the 200 block - measure the deck height and get the block skimmed to give correct deck height .

the head gasket i have for my rebuild will give crushed thickness of about 48thou.
ideal is about 40thou squish .

so i had my block decked to give -0.008 thou deck height - ie piston tops are above the deck.

here is link to a fellow fordsixer and his squish(quench ) feedback.

viewtopic.php?t=38301&highlight=

my engine still in bits in garage - so no engine report from me ......yet.

brett
melbourne

and i also got a cam regrind by ivan tighe:

http://www.tighecams.com.au/cars.htm

300AT : 260 /260 deg cam

should be ok behind the 3 speed auto as not looking to rev the guts out of it .


also got a set of new lifters - the orig had concave faces (even if you dont change the cam is something to check with a straightedge).

tighe sold me a set of lifters for the crossflow ford six- HT900 - wrong type - too tall and have central oiling hole.
what you need are the HT2083 type ( also for the ford FE series V8's).

brett