How much can I shave the heads on my 76 ford 360?
I'm looking for more compression. And how much compression
increase will this give me?

 

Reconsider. Jacking up compression will cause driveability problems. Better; change the compression ratio and cubic inches by installing a 390 crank, rods and Silvolite 1130 pistons for a 9.5 to1 CR. All this is reasonably priced and effective. Check out www.silvolite.com There are other pistons that will give you a 10.5 to 1 CR but you gotta understand 93 octane and fuel octane boosters are in your future.
William in Atlanta

 

Duane, go ahead and cut them. You can cut .060 off the deck of the heads. If you do this, you will need to also cut .060 off from the intake side of the cylinder head. NEVER NEVER NEVER cut the sides of the intake itself. You'll want to use RTV instead of end seals when you put the intake back on. You will also want .060 shorter pushrods. You might also want to get some steel shim cylinder head gaskets instead of the .041 thick felpros....Now I'll assume that your 76 has the D2TE-AA heads on it......so what will this gain you ? The D2 heads have closed chambers, so by cutting them you'll make the chamber smaller, but it is not a huge differance. The real problem with the 360 is that the pistons are more than 1/8th inch down the hole. This means you only have about 8 to 1 with flattops. Most folks use the thick FelPro gasket in stead of the shims when rebuilding, which makes the problem even worse. Even with the cut heads, you will still have less than 9 1/2 to 1. Now about your 360 what pistons are in there ? Don't laugh, I have seen guys use late 390 pistons in a 360 and wonder why they had only 6 to 1. Mistakes can happen. Where is your timing set ? Tuning can help. DF

 

DF, are you sure you take an equal amount off of the intake side of the head as you do the bottom. I suck at algebra but I would think that the intake side should be a lesser amount than the deck surface. Its all based on a 90 degree angle so I would think that it would be half the amount of a block that theoretically had a 180 degree angle. It would be obvious on 180 degree block that .120 total of machining would require another .120 to be removed from somewhere else. Just got me thinking. They do say up to .020 that no other milling needs to be done so there is a little room for error.

 

In the big block ford book by Steve Christ the is a table . this table shows you how much you will need to remove off the intake .....so if 0.020 is removed from the head then 0.028 is removed from the bottom of the intake and 0.020 is removed from the sides of the intake . 0.020 removed from the heads will not show a great increase in compression ...I dont even think 0.030 will show much ,but it will help ....0.030 = 0.035 removed from the bottom of the intake and 0.025 removed from the sides of the intake
I hope this helps
Jon

 

Rat, yep, the same amount on the deck and the intake side of of the head. The deck is at a 45* angle from horizontal, and so is the intake face. The same thing applies to any head that has a 90* intake -to-deck angle. You are right about the .020 'fudge' factor. Most of the heads in the shop where I've done some work get cut less than .010, just to make sure they are flat. We don't cut the intake side of those at all. DF

 

I guess that makes sense. I totally agree about not cutting the intake. If you only cut the heads those heads will work on any FE with any stock intake. If you cut the intake then you have to chop up the next intake if you decide to do a change.

 

Thats right RS, once that intake is cut, it will fit with milled heads and only milled heads. But if the heads are already getting cut on one the decks, cutting the side of the heads to match leaves the intake unmolested. And cutting the side of the head is easier too. Why S Christ didn't put the correct method is beyond me. There are other mistakes too, but overall it is still a good reference. DF

 

This engine has a stock compression ratio of about 8:1. I did
replace the pistons with the same flat top design that was already in the engine. I couldn't find any pistons that would help me increase my stock compression ratio that didn't cost a whole pile of money. I would rather use a higher compression piston than shaving the heads, etc... And I did used the Fel Pro gaskets. So, like you said, I decreased the compression even more. I'm not looking for a 10.5 : 1 compression ratio. Just a decent amount say, 9:1. I still want to run pump gas. I think it just needs a little help. Thanks for the reply. Duane in VA.

 

THe 360 used dished pistons. How far from the top of the deck were they? Are you sure they were completely flat across the top? Do you have a part number?

 

This is somewhat related to the thread, but the issue of 360 vs 390 pistons did come up. If I've got the 360 dished pistons and am changing up to the 390 crank and rods, I shouldn't have any problems, right? I'm not sure which heads I have since they're in the machine shop right now, but I don't really think that should affect my question, even though I am curious. I think they're pre '72 though.

 

As long as the 360 pistons are not skirted you can use them. Of course check the deck clearance before bolting everything together.

 

I am glad you guys are talking about this......I have a 360 .030 and have just received new heads..... Do I need to do any shaving to the heads since the block has been bored? Also, if I were to change to the 390 crank and rods...Do I need to change the pistons and heads again?

 

390 heads and 360 heads are the same for trucks. Any 390 head from any year will work fine on a 360. The only reason heads ever NEED shaved is if they are warped out of tolerance. The pistons may need to be changed. If they are the skirtless type 360 pistons then they will give you a higher compression 390. If they are worn at all you will need to replace them reguardless. Is this a current buildup, worn out engine or a newly rebuilt engine you want to modify? Not sure where you are at in the process so I can't give you very good info on what needs replaced.

 

The pistons were stock and they are very flat, no dishes etc... except for the little valve reliefs. The pistons did come all the
way to the top of the deck. Maybe this will help clarify the issue. The 1976 ford trucks came with the new emissions heads on them. I'm guessing that they have big open chambers, which inherently lower the compression to about 8:1 with flat top pistons. So, finding pistons that will raise my compression are hard to find, because they would actually have to be a dome type piston. Expensive.

I had a 1972 Ford F100 4x4 with a 360 engine in it, with non- emissions heads on it. That motor probably had a 9.5:1 compression ratio. It had right smart more pulling power than the one I have now, the 1976 Ford F100 4x4 with the 360 engine with the emissions heads.

I believe with this in mind I could find a set of 65-70 model 390
2v heads and bolt them on and increase my compression to about
9.5-10:1 ratio. What's you thoughts on this? This is the whole
reason I was looking to shave my heads about .050 - .060 to
hopefully increase my compression to about 9:1. Which is all I was
looking for anyway.

The way they made the 360 was just shorten the crank a little
and slap a set of 390 heads on it. But then they went to emmissions heads. Screwed it all up. Thanks for all the replies.
Duane in VA.