Stock Heads
Thread Starter
|
Senior User
Joined: Jan 2002
Posts: 109
Likes: 0
From: Green River USA
Stock Heads
Ok, I know that the Aussie heads are superior in design but I just don't think that they are worth all the trouble of bidding for if you aren't building a serious engine. That's my opinion anyways. My question is, what is the combustion chamber volume of stock heads for a 1978 400? The number that sticks out in my mind is 76cc but 72cc also sounds like it might be. The number that I really need is the combustion chamber volume for a pair of stock PORTED heads. Probably like 80cc? And how much can you deck the block before you typically have to get shorter pushrods or do other things to compensate? Thanx in advance.
Senior User
Joined: Aug 2001
Posts: 250
Likes: 0
Stock Heads
You might want to get them cc'd to make sure of the size. You should also talk with your machine shop about decking the block. Work out the numbers with them. They will have the info on your piston choice. I would also keep the compression below 9.5:1 with those heads.
Junior User
Joined: May 2002
Posts: 90
Likes: 0
From: Eudora USA
Stock Heads
I have a 78' 400 and they cc'd my heads at 78cc's I am also runing 9.55 comp on 90 pump gas. I can use 89 but it just bairly pings. The stock heads are fine for mild use but dont make the mistake I did and invest a grand in your heads just to find out that there is a giant restricting mountain in the exhaust port. By useing the closed chamber heads you can run higher comp and use dish pistons to impove flame front travil and they also have wide open exhaust ports. The rule of thumb I would follow is if your spending as mutch on your head work as on a pair of bare aussies would cost, buy the aussies. You will be mutch happyer with them anyway.
-Jim
-Jim
Thread Starter
|
Senior User
Joined: Jan 2002
Posts: 109
Likes: 0
From: Green River USA
Stock Heads
The emissions bumps don't worry me at all because my father has ported several pairs of smog 400 heads and he says that it's no biggie to get rid of those. And after the porting, flow will be at least somewhat comparable to the aussie's. But what I'm worried about is compression. I'm using kind of a wierd setup - I'm bushing my 400 rods so that I can use 351C pistons. I found some nice hypereutectics by KB (Claimers, to be specific) that have 4.5cc valve reliefs. With 78cc heads and no machining whatsoever, I'm getting a 9.1:1 compression ratio. I want 9.5 and that shouldn't be a problem because of resurfacing. I could also have the block decked. I've been told that's a very feasible thing to do because the 400 deck clearance is horrible (about .055)! So, at this point, my course of action is looking something like this:
1.) Port and Polish heads and do whatever else needs to be done to them
2.) Have the heads resurfaced/machined and then have the combustion chambers cc'd
3.) With this actual combustion chamber volume, run a calculation to see how much I need to have the block decked
4.) Have the block decked to achieve 9.5:1 compression ratio!
Does that sound like the process I should go through? Am I going to run into any problems with pushrod length because of the machining? Are there any other problems I'm not accounting for? What do you think the combustion chamber volume is gonna be on a pair of ported, resurfaced heads? I was thinking the porting would make them about 80cc and the resurfacing/machining would bring them down to 76cc. Sound about right? Thanx for all the help
1.) Port and Polish heads and do whatever else needs to be done to them
2.) Have the heads resurfaced/machined and then have the combustion chambers cc'd
3.) With this actual combustion chamber volume, run a calculation to see how much I need to have the block decked
4.) Have the block decked to achieve 9.5:1 compression ratio!
Does that sound like the process I should go through? Am I going to run into any problems with pushrod length because of the machining? Are there any other problems I'm not accounting for? What do you think the combustion chamber volume is gonna be on a pair of ported, resurfaced heads? I was thinking the porting would make them about 80cc and the resurfacing/machining would bring them down to 76cc. Sound about right? Thanx for all the help
Junior User
Joined: May 2002
Posts: 90
Likes: 0
From: Eudora USA
Stock Heads
The smog bump is not what we are talking about with the 400 heads, they have a raised water jacket that pinches the port to half its sise. You cant tell untill you see the heads side by side. I gess it would be fair to say the 400 heads have a difernt exhaust port design, they are shaped diferntly. The bump is on the lower part of the port and goes from one side to the other, all the way across. A bump dose not describe it well its giant and blends well to the port.
-Jim
-Jim
Junior User
Joined: Nov 2001
Posts: 87
Likes: 0
Stock Heads
>The emissions bumps don't worry me at all because my father
>has ported several pairs of smog 400 heads and he says that
>it's no biggie to get rid of those. And after the porting,
>flow will be at least somewhat comparable to the aussie's.
>But what I'm worried about is compression. I'm using kind of
>a wierd setup - I'm bushing my 400 rods so that I can use
>351C pistons. I found some nice hypereutectics by KB
>(Claimers, to be specific) that have 4.5cc valve reliefs.
I just did the same exact thing with my 400. I bought my Claimer pistons from beckracing.com for $160. You will have to have you crank balanced with these pistons. They are quite a bit lighter than the stockers.
>With 78cc heads and no machining whatsoever, I'm getting a
>9.1:1 compression ratio.
You should be getting 9.25:1 actually, with 10.295" deck hight,78cc heads,4.5cc valve relief, 1.67" compression height,6.58" rods,and .045" thick head gasket. You will have .045" deck clearance; if you mill the heads or block .015" you will get 9.52:1.
>I want 9.5 and that shouldn't be a
>problem because of resurfacing. I could also have the block
>decked. I've been told that's a very feasible thing to do
>because the 400 deck clearance is horrible (about .055)!
Be carfull not to take too much off the deck or it will become too thin and likely crack. Just do enough to clean it up. Take the rest off the heads. The clevelands don't have a lot to take off from the deck. Talk to a machine shop about that one.
>So, at this point, my course of action is looking something like
>this:
>1.) Port and Polish heads and do whatever else needs to be
>done to them
Don't touch the intake ports except gasket matching. Just about any other intake mods will hurt flow unless you have a flow bench handy.
However, goto town on the exhaust ports. Remove the exhaust bumps, smooth the valve guide bosses and casting lines, port match, polish the crap out of the port and combustion chamber. Back cut the valves too. And if I were you, I would install the 4V valves(2.19"intake/1.71"exhaust). They are larger and flow way better at low lift than the stock valves. This is the best mod you could do to your heads. Here's the flow #'s. http://www.waldens.com/waldens/351heads.htm
>2.) Have the heads resurfaced/machined and then have the
>combustion chambers cc'd
>3.) With this actual combustion chamber volume, run a
>calculation to see how much I need to have the block decked
>4.) Have the block decked to achieve 9.5:1 compression
>ratio!
All very good ideas.
>Does that sound like the process I should go through?
Yes!
>Am I going to run into any problems with pushrod length because
>of the machining?
No. unless you take more than a combined .020" you wont need different pushrods. You could even get away with .025".
>Are there any other problems I'm not
>accounting for?
Just the balancing of the crank I mentioned earlier.
>What do you think the combustion chamber
>volume is gonna be on a pair of ported, resurfaced heads? I
>was thinking the porting would make them about 80cc and the
>resurfacing/machining would bring them down to 76cc. Sound
>about right? Thanx for all the help
I don't know if you are looking at this quite the right way. If you port the heads you wouldn't be removing any material from the combustion chamber therefore the cc's would stay the same. Porting removes material from the intake and exhaust runners. Now if you were to polish the combustion chamber that would remove some material. I would guess a good polish job would be worth 2-3cc's.
And when you mill the heads say .010", just think of it as the same as milling the block .010". It is much easier this way.
You should expect 400hp and 450ft/lbs with a matched cam.
This is all just my opinion, talk to others and do what you want to do. The machine shop that will be doing the work would be the best people to listen to.
Sorry for being so long winded.
79 F150 4x4 410m Built Ford Tough!(9.1:1,KB pistons,custom Comp Cams X-Treme 210/218-.508/.524,roller rockers)/c6/3.5:1 gears,4.11:1 soon, Edelbrock 750, 285/75R16 BFG Mudders on alumn. mags with New Drk. Blue paint.
65 Ranchero 170-6, 3on the tree, solid mags, New Bright Yellow paint
>has ported several pairs of smog 400 heads and he says that
>it's no biggie to get rid of those. And after the porting,
>flow will be at least somewhat comparable to the aussie's.
>But what I'm worried about is compression. I'm using kind of
>a wierd setup - I'm bushing my 400 rods so that I can use
>351C pistons. I found some nice hypereutectics by KB
>(Claimers, to be specific) that have 4.5cc valve reliefs.
I just did the same exact thing with my 400. I bought my Claimer pistons from beckracing.com for $160. You will have to have you crank balanced with these pistons. They are quite a bit lighter than the stockers.
>With 78cc heads and no machining whatsoever, I'm getting a
>9.1:1 compression ratio.
You should be getting 9.25:1 actually, with 10.295" deck hight,78cc heads,4.5cc valve relief, 1.67" compression height,6.58" rods,and .045" thick head gasket. You will have .045" deck clearance; if you mill the heads or block .015" you will get 9.52:1.
>I want 9.5 and that shouldn't be a
>problem because of resurfacing. I could also have the block
>decked. I've been told that's a very feasible thing to do
>because the 400 deck clearance is horrible (about .055)!
Be carfull not to take too much off the deck or it will become too thin and likely crack. Just do enough to clean it up. Take the rest off the heads. The clevelands don't have a lot to take off from the deck. Talk to a machine shop about that one.
>So, at this point, my course of action is looking something like
>this:
>1.) Port and Polish heads and do whatever else needs to be
>done to them
Don't touch the intake ports except gasket matching. Just about any other intake mods will hurt flow unless you have a flow bench handy.
However, goto town on the exhaust ports. Remove the exhaust bumps, smooth the valve guide bosses and casting lines, port match, polish the crap out of the port and combustion chamber. Back cut the valves too. And if I were you, I would install the 4V valves(2.19"intake/1.71"exhaust). They are larger and flow way better at low lift than the stock valves. This is the best mod you could do to your heads. Here's the flow #'s. http://www.waldens.com/waldens/351heads.htm
>2.) Have the heads resurfaced/machined and then have the
>combustion chambers cc'd
>3.) With this actual combustion chamber volume, run a
>calculation to see how much I need to have the block decked
>4.) Have the block decked to achieve 9.5:1 compression
>ratio!
All very good ideas.
>Does that sound like the process I should go through?
Yes!
>Am I going to run into any problems with pushrod length because
>of the machining?
No. unless you take more than a combined .020" you wont need different pushrods. You could even get away with .025".
>Are there any other problems I'm not
>accounting for?
Just the balancing of the crank I mentioned earlier.
>What do you think the combustion chamber
>volume is gonna be on a pair of ported, resurfaced heads? I
>was thinking the porting would make them about 80cc and the
>resurfacing/machining would bring them down to 76cc. Sound
>about right? Thanx for all the help
I don't know if you are looking at this quite the right way. If you port the heads you wouldn't be removing any material from the combustion chamber therefore the cc's would stay the same. Porting removes material from the intake and exhaust runners. Now if you were to polish the combustion chamber that would remove some material. I would guess a good polish job would be worth 2-3cc's.
And when you mill the heads say .010", just think of it as the same as milling the block .010". It is much easier this way.
You should expect 400hp and 450ft/lbs with a matched cam.
This is all just my opinion, talk to others and do what you want to do. The machine shop that will be doing the work would be the best people to listen to.
Sorry for being so long winded.
79 F150 4x4 410m Built Ford Tough!(9.1:1,KB pistons,custom Comp Cams X-Treme 210/218-.508/.524,roller rockers)/c6/3.5:1 gears,4.11:1 soon, Edelbrock 750, 285/75R16 BFG Mudders on alumn. mags with New Drk. Blue paint.
65 Ranchero 170-6, 3on the tree, solid mags, New Bright Yellow paint
Thread Starter
|
Senior User
Joined: Jan 2002
Posts: 109
Likes: 0
From: Green River USA
Stock Heads
Just one more question. My brother was running a hot motor (425hp/500'#, WITHOUT headers) on 9.8:1 compression. We always assumed he was running 10.5:1 but we ran the calcs and it is 9.8. This troubles me slightly because if he ran 10.5:1 on midgrade, I know I can run 10:1 on it too. But now I'm not so sure. Is 10:1 compression too much? And I don't mean midgrade exclusively, I could live with running it on premium. So what kind of numbers could I expect with 10:1 c/r and a matched cam? What kind of duration figures would you suggest (I have an auto)? Thanx for all the help.
Trending Topics
Junior User
Joined: Nov 2001
Posts: 87
Likes: 0
Stock Heads
>Just one more question. My brother was running a hot motor
>(425hp/500'#, WITHOUT headers) on 9.8:1 compression. We
>always assumed he was running 10.5:1 but we ran the calcs
>and it is 9.8. This troubles me slightly because if he ran
>10.5:1 on midgrade, I know I can run 10:1 on it too. But now
>I'm not so sure. Is 10:1 compression too much? And I don't
>mean midgrade exclusively, I could live with running it on
>premium. So what kind of numbers could I expect with 10:1
>c/r and a matched cam? What kind of duration figures would
>you suggest (I have an auto)? Thanx for all the help.
With 10:1 compression you should be fine with premium; as long as you run a large cam with approx. 230 or more duration @.050" lift. Go with a split duration cam. Like a 232in/240ex @.050". This will keep cylinder pressure right at or below 175psi. You will also have to be carefull with the advance curve of the distributor so it doesn't advance too much too early. You will also need a higher stall converter with the auto tranny with a cam that size. I would say at least a 2000rpm stall. A 2500rpm stall would work nice. All of this should produce about 425hp@5500 and 465-475ft/lbs@4400 without headers. With decent headers, this thing will come alive. At least 450+hp@5500 and 500ft/lbs@4700. With this kind of power you'll want at least a 750cfm carb. Again, this is just my opinion.
79 F150 4x4 410m Built Ford Tough!(9.1:1,KB pistons,custom Comp Cams X-Treme 210/218-.508/.524,roller rockers)/c6/3.5:1 gears,4.11:1 soon, Edelbrock 750, 285/75R16 BFG Mudders on alumn. mags with New Drk. Blue paint.
65 Ranchero 170-6, 3on the tree, solid mags, New Bright Yellow paint
>(425hp/500'#, WITHOUT headers) on 9.8:1 compression. We
>always assumed he was running 10.5:1 but we ran the calcs
>and it is 9.8. This troubles me slightly because if he ran
>10.5:1 on midgrade, I know I can run 10:1 on it too. But now
>I'm not so sure. Is 10:1 compression too much? And I don't
>mean midgrade exclusively, I could live with running it on
>premium. So what kind of numbers could I expect with 10:1
>c/r and a matched cam? What kind of duration figures would
>you suggest (I have an auto)? Thanx for all the help.
With 10:1 compression you should be fine with premium; as long as you run a large cam with approx. 230 or more duration @.050" lift. Go with a split duration cam. Like a 232in/240ex @.050". This will keep cylinder pressure right at or below 175psi. You will also have to be carefull with the advance curve of the distributor so it doesn't advance too much too early. You will also need a higher stall converter with the auto tranny with a cam that size. I would say at least a 2000rpm stall. A 2500rpm stall would work nice. All of this should produce about 425hp@5500 and 465-475ft/lbs@4400 without headers. With decent headers, this thing will come alive. At least 450+hp@5500 and 500ft/lbs@4700. With this kind of power you'll want at least a 750cfm carb. Again, this is just my opinion.
79 F150 4x4 410m Built Ford Tough!(9.1:1,KB pistons,custom Comp Cams X-Treme 210/218-.508/.524,roller rockers)/c6/3.5:1 gears,4.11:1 soon, Edelbrock 750, 285/75R16 BFG Mudders on alumn. mags with New Drk. Blue paint.
65 Ranchero 170-6, 3on the tree, solid mags, New Bright Yellow paint
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Elder User
Joined: Sep 2001
Posts: 887
Likes: 1
From: Jax FL
Stock Heads
400 2v heads - This is my theory - I have an early 400 motor (1971). the casing info says it was cast at the DIF (detroit industrial foundy), the heads have the same casting, my heads are a little different than "normal" 400 heads. so you may want to check the casting plant. I have not checked a lot of 400 heads, but so far my engine block is just a little off as well. I think I have regular 351 2v heads vice the 400 heads.