Hi all, I have a '72 200 I6. I've been reading about thee compressoin dropping and dropping over the Maverick production years but I havent found much info on what changed (pistons? head?) Im guessing it's not the rods. Ya know, compression is power and it don't cost mpg. Not that I'm gonna fry em. It needs a valve job and If I could up the squeeeze with a different head... Can anybody point me to a good source of info? Also interested in I6 interchange secrets.
fordsix.com/forum on all the charts ive seen about 6 cylinder compression across the maverick run compression seems to fall between 8:1 and 8.7:1, really not much. if your taking the head off for a rebuild you should get the shop to mill it down. this makes the combustion chamber smaller=more compression. aftermarket head gaskets are a little thicker then the stock steel one so if you replaced that gasket without a mill job youd actually be loosing some compression. according to the chiltons guide your 72 200 should be making 90hp@4000 rpm, 154ft lbs of tq@2200rpm with a 8.3:1 compression ratio and all the 200s seem to have a bore x stroke of 3.680x3.130 so im guessing compression was adjusted through either piston design or deck hight unless you have the green to pick up the new aluminum I6 head for 2 grand your better off working of what you have. i believe 250 heads have a bigger intake log and valves and should bolt on to a 200 block. bigger carb is also a good way to go. in my sig you can see the 2bbl i swapped on to my 250. i went the easy way and used a bolt on adapter plate to fit the 2bbl carb on the 1bbl hole but alot of guys have had their head drilled out so the 2bbl fits right on the intake. in the tech article section i wrote an article about going about the swap you could look into. even on a bone stock engine you'll feel a gain. http://www.maverick.to/mmb/showthread.php?t=36020 the biggest issue to over come with an I6 is the tiny valves. it has potential but with their size its hard to feed, even to the point where opening up the exhaust with a header has no performance gain since the manifold flows well enough but it still sound cooler
I wonder the same things... On the 302s, everything was altered except the cylinder heads. The block deck height was increased .020" inch, and pistons were changed. Both in the quest to drop .5 compression a year between 71 and 73. All while chambers kept at 58cc. When the heads were finally overhauled later, the block height returned to original height and chambers got huge. Anyway, I am curious as my son is working on a 200... Will a 250 head really fit?
Yes! Modern manuals don't have much info, however... If you find old Chiltons or Motors manuals, they have detailed info on engine specs. There is one or two more manuals from that era, but I can't recall the names. Anyway, find the editions that were current when your car was made. You will find a wealth of details on your engine. Check flea markets and yard sales, eBay if you must. Maybe used book stores??? I have several at my shop. I would share if you were close, but they are not for sale.
this is a good article to read about head swaps from ford six http://fordsix.com/forum/viewtopic.php?t=1027
Thanks Thanks for all the good info. I probably will be sticking with whatever head is on it. It's probably the original. Then mill it to get what I want. I may put hardened exhaust seats if it doesn't already have them. BTW, Nice ride Tony! Gotta love a nicely detailed engine. On a different motor (mopar 318), I ran about 9.4 on 89 octane but had to retard the timing to avoid ping. Milled the heck out of a pair of early closed chamber 318 heads cuz there were no performance pistons available for 318 in those days. Of course, that killed any power/mpg gain from the compression but If I wanted a little more soup for cruise night, I'd put in 93 gas and a can of 104 octane boost and bump the total advance to about 34. $2k aluminum head! I know I'll never go there but who's making that? A few years ago, Clifford had some stuff on their site about a crossflow head they were gonna do, but when I checked back, those pages had vanished. I never thought about my old Chilton's. I have a truck/van book for 71-78. It only shows the 200 for 73-75, so the specs are for the "smog motor" but valuable info anyhow. A 2bbl would be great. Nice tech article. Not ready for that yet though, cuz there's a lot of other stuff to spend on. I was looking on the Brazilian ebay and saw a picture of a Mav 6 with the carb on the passenger side and......The Exhaust On The Driver's Side! Don't know if that motor grew there or not and I don't speak Portuguese. I thought only the Aussies had crossflow engines. Not that I'm gonna go looking for an exotic engine but just out of curiosity, anybody know anything about this? Thanks again
the aluminum head is made by ford six but it is ready to run with detachable intake and all kind of goodies for everything it is i'd say its a fair price but probably aimed more toward more HI-po builds with turbos etc. the head you seen is probably a cross flow, by the time you found a good one and got it shipped up you could be in it pretty deep already $$$ yea my engine cleaned up pretty nice. i degreased the hell out of it, sprayed it off, put that chrome valve cover on and gave it a nice coat of ford blue engine paint after i taped off everything of course. over spray on plug wires looks like hell lol i used black on the exhaust manifold
