View Full Version : 390 heads and intake question
03-12-2012, 12:59 AM
Greetings FE people,
I'm replacing the heads on a 1967 390 with some that have larger intake ports. The heads I'm installing are C4AE-6090G. The old ones were C7AE-xxxxx. Do I have to use an intake manifold with larger ports to reap any benefits? The heads and intake are stock cast iron ford parts.
Also, is there such a thing as porting the intake? The ports on the newer heads are about 3/8 inch longer in the down measuement. (Does that make sense?)
Should I look for a used Edelbrock Performer RPM as described in Barry Rabotnick's "Max performance Ford FE Engines" book? Will there be all that much difference in performance?
As you can probably tell this is the first time I've ever done anything with an engine.
thx for any advice!
regards, DAve J.
PS: I can post pix if that helps
03-12-2012, 03:08 AM
Dave, be careful in your choice of heads and intake manifolds. There were about fifty different intake manifold choices. The only safe way I know for sure, is to match the manifold to the heads.
It is typical for the intake manifold ports to be smaller than the matching head ports because mixture velocity is faster in the manifold (and that's what you want).
Let's back up a moment... What features are you looking for? Low end torque, high rpm for speed? Depending on what you want, sometimes large valves bog at low rpm's. That's why truck heads typically have smaller diameter valves. They don't bog, but they aren't designed for racing.
If you're looking for horsepower, you may consider a higher compression ratio by shaving the heads and intake to match. FE's aren't easy to do. You'll get more ponies but now we're talking Premium gas. High compression is more likely to blow head gaskets, but it has been done.
I admire your tenacity but I hate to see you spend a lot of money on a cast iron engine. Heads are the heart of every engine. I know you don't want to pop for aluminum, but if you machine cast iron heads and ready them for today's gas (new stainless valves, viton seals, exhaust valve seats, bronze guides, new springs, and decking) it will cost nearly what aluminum heads go for. What do you end up with? Used cast iron heads worth ~$300. If you bought aluminum for $1,500, you could always get a grand back. The difference in performance is huge and so is the weight savings.
Want a good, fast engine? Get a used Mustang engine. Then, buy a scrapped Mustang and use it for the EEC, cables, and connectors. I think you would save money and you'd end up with a EFI Thunderbird (and a great project). All the parts are available at decent prices. Just my humble opinion. - Dave
03-12-2012, 11:30 AM
Thx Dave, I remember reading something about the smaller valves being for more low end torque, and the larger valves helping flow, thus working better at high RPM when air is flowing at a much higher rate. I had no idea about the intake manifold port size though. Your explanation of the "mixture velocity" needing to be faster is something I didn't know and helps me a ton!
When I bought my toploader I told the guy I was putting it on a 390. He just happened to be a retired county guy that maintained police cars for Albuquerque way back when. He remembered he had these heads that were rebuilt just sitting on a shelf and asked if I wanted them for a couple of hundred bucks. Anyway, I'm using them for now, hopefully I can get away with a lead additive in my gas for a 1,000 miles, and then replace them in about 5 years (when I retire). At that time I will have tons of free time to do a proper build of this motor.
The engine noise I had explained on a different post DID turn out to be a blown head gasket. I'll be checking my block deck where it blew to make sure it's flat and true, and I'll be sure to follow the installation and torquing sequence described in my book by Barry Rabotnick very thoroughly. Oh, and my rocker assembly's have different shafts, more signs that the motor has already been gone through before. The oil passages are different, they were very clear though - that's a good sign. The push rods and rocker arms all look to be in great shape and show no signs of wear on the contact surfaces. I'm taking tons of pictures as you told me before. I took this week off work so I'm getting a lot done. The trick is going to be figuring out the "Z bar" and related hardware. I found one on Ebay from a 58-59 Fairlane, Ranchero, Skyliner that looks identical to the parts I have a picture of. I could REALLY use some pictures of under the hood on this 59 T-bird to see how they go in and where they all mount.
You had said to use the brass block plugs. I'm also going to get a larger oil pump shaft - can you tell me where on line I might find them? Rockauto and our local Autozone don't sell them.
As always, thank you for your help and advice!
- Dave J
03-12-2012, 12:58 PM
Here's a start. Doesn't show too much. Work these and the Illustrations.
PM an email address and I'll send full size files.
03-12-2012, 06:22 PM
Hey gents, Can anyone tell me how to remove this plate off my intake manifold? I'm guessing this is some type of valley tray, as there wasn't one on top of the motor when I pulled the intake. Sure looks like a lot of baked on oil from the heat the cross overs generate.
thx, dave J
PS: I found a picture of an intake that looks identical to mine - it says it's a 66 - 69 390 high performance?
03-12-2012, 07:01 PM
Hm, OK. I browsed for my 2 small pictures and attached them. Can anyone tell me what I did wrong?
03-12-2012, 07:07 PM
The plate attached to the intake manifold is held on with drive screws http://www.fastenal.com/web/products/detail.ex?sku=32213 They can be backed out with a chisel or a slot cut for a screwdriver. There should have been a valley pan tucked under the tabs of the head gaskets, it helps direct oil away from the intake. Good luck, Bob C
03-12-2012, 08:35 PM
Thx Bob, from what I found using google the missing valley pan would explain all the crusty burnt oil stuck under that plate! It said it is suppose to keep the oil away from the cross over exhaust ports.
I've been cleaning, degreasing, and chipping away like a mad man today. Learning the hard way!
Thx for the help, I'll try to twist those drive screws out now. I'll buy a valley oil tray too.
regards, Dave J
03-13-2012, 03:07 AM
Dave, you're in NM. Block off the exhaust crossover and eliminate the heat riser on your RH exhaust manifold. The last thing you need is to heat up your fuel in the Mojave.
03-13-2012, 10:34 AM
Thx Dave, I plan on putting headers on the car, so I won't have it anyway.
Do I need to have both the valley tray and the pan that is attached with the drive screws installed? Is there some reason a car would be built without the valley tray like mine was?
Oh, and what kind of sealer do you use when installing the freeze plugs?
When I chiseled out the drive screws it was like some one baked a cake under the pan!
Can you tell me what I'm doing wrong when I try to insert pictures on posts.
thx a ton, Dave J
03-13-2012, 11:49 AM
Hi Ken and all. I brought those pix you sent me up in Adobe Reader, pushed the Ctrl and Prt Scrn Sys Rq buttons to copy them. I took each one into a graphics editor, clicked on Paste and got the whole screen shot. Then I cropped the pictures and saved them as a .jpg file. Now they can be posted to the Forum. David, since you are a Paid Member, I do not know why you were not able to upload those pix yourself. You should be able to do so. Here are the pix that Ken annotated.
03-13-2012, 12:28 PM
Thx Ray, Ken had already sent them to me in an e-mail.
Here's a test of my upload. These are the pix I took yesterday of my manifold and the "dark chocolate cake" that was baked under the intake. I re-sized them to 217KB.
Ah ha! I just got an error that the max file size is 145kb!
Duh,,, my mistake. Here they are.
- Dave J
03-13-2012, 05:37 PM
Thx Dave, I plan on putting headers on the car, so I won't have it anyway. Yes, but your intake will still transfer exhaust gasses across your carb. Block it off.
...Oh, and what kind of sealer do you use when installing the freeze plugs?...I like using RTV (bathtub calk). There is a secret to this: Make sure your surfaces are oil-free and dry before you start. Use lacquer thinner to remove oil. Spread a THIN layer of RTV on your surfaces and assemble. If you use too much, pieces of RTV will be in your cooling system, forever.
Some assemblers use sealer that never hardens. I use RTV because it stays pliable in extreme temps and it is easy to remove. All my cork gaskets get a very thin layer of RTV, and their mating surfaces as well. Again, they 'gotta be clean'. - Dave
03-13-2012, 05:45 PM
Hey Dave, In my blog for "390 heads and intake question" you said that I could block the crossover in my intake manifold. Can you tell me how you would do that? I read online that some guys use epoxy, others talked about using sheet metal.
If I do that do I still need a valley tray and manifold shield?
thx in advance, Dave J
I use shim stock, which is thin sheet metal. You can block both sides or just one side. I would do both sides (just to make sure).
Simply slide a sheet metal cover over the intake manifold port where the exhaust gas enters on both sides. Then, no manifold shield is necessary.
03-13-2012, 07:58 PM
Thx Dave, do I still need a valley tray? Sure is weird that this thing didn't have one.
regards, Dave J
03-13-2012, 10:25 PM
It must have been left out by whoever was in there last. Having the tray in place will help control oil mist in the valley and prevent expulsion through your breather or pvc system if your using one, (there is no up side to running a road draft tube) which is a good idea even if not originally equipped that way. Mike
03-14-2012, 12:57 AM
The motor is actually out of a 1967 LTD and doesn't have the draft tube. It has a PVC in the valve cover. I'll have to find a valley tray on E-bay I guess. They sure are pricey for a piece of sheet metal.
03-15-2012, 02:34 PM
Hey guys, for the sheet metal stock to block the cross overs; would something like the thickness of Pro panel roofing be about right? How does it hold in place? Can I just hold it there with some gasket sealer and then assemble the rest?
Also, would it be OK to just put epoxy in the head portion of the cross over instead? Being that the heads are new and clean I thought that might be easier.
thx, Dave J
I ordered a valley pan on E-bay $80 with shipping! Dang, that's pricey.
03-15-2012, 03:11 PM
Use some steel shim stock with your gasket. Epoxy breaks down under heat, so don't use that on any hot engine parts. I don't know about using roofing metal, but stay away from aluminum. - Dave
03-15-2012, 03:34 PM
Thanks Dave, will do.
Just trying to make some building notes so that when I get the block back and I start building I can refer to my notes and get going.
appreciate all your help!
12-02-2012, 10:10 AM
I'm at a similar point. I suppose I can replace the screws with small bolts and lock washers. Whats that steel wool stuff in there?
12-02-2012, 10:33 AM
I re-read the last few posts on this string and don't quite follow your question Yadkin?
12-02-2012, 10:57 AM
I'm talking about the sheet metal baffle under the intake manifold. After I remove the screws I assume that I can replace them with small bolts and lock washers?
Also, there is a steel mesh fabric in the rear section of the baffle, apparently to reduce oil flow to the down draft (or pcv) system. I'll try and soak this in solvent to clean it but if I can't get it clean I'll have to replace it. I'm not sure what type of material would be appropriate to use as a replacement.
12-02-2012, 12:51 PM
I sued stainless steel scrubbing pads (withouth soap) from the grocery store in the valley pan space on my Y-Block. SS screen (hardware cloth) may work also.
12-02-2012, 03:26 PM
Two thoughts came to mind when you said, Y-block. I don't mean to get sidetracked but the Y has a separate 'valley pan' as I call it.
I had all my sheet metal chromed and assembled with stainless.
While the engine was still on the stand, I noticed the cam got REAL HARD to turn. I scratched my head for ten minutes over that one. Turns out, if the valley pan screws are too long, they squeeze the cam bearings underneath. Thank God nothing was harmed but I learned a lot about the engine and the dangers of using long bolts that day. Sometimes studs and nuts work better.
The second thought regarding the draft mesh makes my skin crawl. Shedding pieces of spun steel can get into your oil pump and really screw it up. I don't know if ScotchBrite material is heat resistant enough but it might be suitable to use. Stainless mesh isn't necessary but it is still good as long as it holds together. - Dave
12-02-2012, 07:09 PM
The shop building my engine claimed they always used the stainless steel material when needed. Mine was missing from the "box" on the pan's underside. Scotchbrite won't stand the heat, the copper scrubbing material could corrode and crumble in time. They have also used ss window screen wadded up to condense the fumes, but you have to buy a large amount and the scrub pads are in a useable size/shape ready to use.
(Hope you also checked the oil passages to make sure the hole in the cam bearing was fully open.)
12-02-2012, 08:17 PM
I love the idea of using copper window screen. I suppose aluminum would work as well.
Re: Y-block... read the second paragraph CLICK HERE (http://home.comcast.net/~simplyconnected/59Ford/EngineParts/Block/BlockAssembly/default.htm)
I have found some Y-blocks offer less resistance when I blow down that center cam bearing hole. I have also sent a loooong 1/4" drill bit down to open the cam bearing hole just a little more.
My rocker arms have great oil flow at every valve stem. I also plugged the drain so the shaft is pressurized. That raised my idle oil pressure to 40-psi. My Y's run at about 55-psi. - Dave
12-02-2012, 11:17 PM
I wouldn't use copper or aluminum because of dissimilar metals and galvanic corrosion. I ll ask my machinist what he uses.
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