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Took my head to the machine shop to have seized exhaust manifold bolts removed, the exhaust manifold was also way off and he’s going to sand that for me. He checked the head itself and said “ its really close - im Concerned about this spot between piston five and six where there is no resistance to my gauge, its been resurfaced before but it was done on a belt sander - in the old days this probably would work, nowadays with Fel-Pro gaskets I would recommend getting it resurfaced.“ I went back-and-forth and finally said OK let’s do it. Basically, this guy saw me coming! But all said and done he said it’s gonna run me only $210 Including bolt removal.

My question is, can I expect to make any adjustments when I put this thing back together? he said I may notice a negligible difference in compression but that no adjustments would be needed when putting it all back together. Just wanting 2nd opinion.

thanks!
 

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If you are gonna have machine work to flatten sealing surface of head, the you might as well take enough off to have a bump in compression. This is one of the tricks to do when “hopping” up the little six. You have to know some specs and do some math, but might as well get all benefits you can. There is not one recipe for this, just depends on what parts you have to start with. You are “milling“ the head or shaving it flat. you also need to know how far down in the hole your pistons are when at Top Dead Center. Get the falcon six handbook to know more than you ever wanted to know...read up....also go here:

 
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i agree with milling the head to increase power.a few things here, the stock head gasket on these engines was a .025" steel shim gasket. modern replacement gaskets are generally .053" compressed thickness, meaning that you need to take .025" off just to get back to stock compression. after that is when you start bumping the compression up. usually we suggest going another .025", or a total of .050" to get a compression increase. and that is certainly doable with out issue. if you are using a later model head with the larger chambers, we suggest going as much as .090" to gain compression.

if you have hydraulic lifters, this should be no problem. if you have mechanical lifters, you should invest in an adjustable set of rocker arms, perhaps you can find a set from an old 144-170. the rocker shaft and arms all interchange with the later non adjustable rockers and shaft.
 

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I do understand increasing power by increasing compression, but here is where I am coming from - removal of the head was the extent of my inner engine work - while I can rebuild the carb and set timing, I have no idea if I have hydraulic or mechanical lifters and have no idea what the difference is. The car gets about 1000 miles a year going 40mph on backroads of WNC so increasing power isnt my primary concern. I just need to be able to put it back together without blowing it up. So, is a small resurfacing likely to cause a need to do any adjustments once I get the head back on?
 

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You can have a machine shop do the milling. They can shave a little or a lot. It’s up to you. Minimal shave, possible slight loss of performance, minimal install. More shave, more Performance, maybe minor adjustents or new parts. The links I gave Will explain, or take pics and post them, and we can advise. Your call.
rbohm knows the in’s n outs better than me, but I’m always learning...and I’ve been down a few of these rabbit holes. You always come out leaner on the other end. Or is that because my wallet got thinner?
 
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coupster & rbohm have some good info.

But, to answer your question. :) You should be good. Just find out how much was milled off so you can figure out your new compression.

With higher compression you might run a littler warmer with coolant temps.
 

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coupster & rbohm have some good info.

But, to answer your question. :) You should be good. Just find out how much was milled off so you can figure out your new compression.

With higher compression you might run a littler warmer with coolant temps.
i agree, and thank you!!!
 

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You have to determine what head gasket you had. Was it the original style steel gasket? If it was you would actually loose compression. But since you say i5 has been previously resurfaced, there is. A good chance it was a newer style gasket and you won’t see any real change.
 
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I do understand increasing power by increasing compression, but here is where I am coming from - removal of the head was the extent of my inner engine work - while I can rebuild the carb and set timing, I have no idea if I have hydraulic or mechanical lifters and have no idea what the difference is. The car gets about 1000 miles a year going 40mph on backroads of WNC so increasing power isnt my primary concern. I just need to be able to put it back together without blowing it up. So, is a small resurfacing likely to cause a need to do any adjustments once I get the head back on?
chances are that since your car is from 65, you have hydraulic lifters, so you are goo to go there. ford did that as a running change sometime in late 63 iirc. as for increasing compression, that has more benefits that just increasing power. it makes for better driveability as well, and improves fuel economy. you dont need to go overbard on this, like i am going to do with my later model head. its has the larger chambers, but i need to get chamber size down to around 53cc to raise my compression back where i want it when i build my 170. i am looking at a cut of about .090". fr you a cut of about .060" will do nicely.
 

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Discussion Starter #10
Thank you all for your replies and help - as an update, I picked up the head and manifold, 4 broken bolts removed, manifold was milled and the head was milled .009, $260 total. Looked beautiful. Put it back together, started right up - no adjustments, no issues, sounds great, and no more exhaust leak now that I Have all 11 bolts in the manifold.
 
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