Hello everybody, i have a 390 in a 71 ford custom 4x4. I would like to get some suggestion on what the best camshaft, carb, intake manifold, headers, and what else you guys put on for hp. I have been reading a lot for a week or two now and see that people use the edelbrock preformer rpm intake manifold. I would like to know how many cfm carb would be adequate. And only one more thing, what order would you get this and approx price and hp/torque gains will i make. Thanks so much guys

 

Well, the ideal situation would be 9.5:1 compression, Crane 344341 cam, Edelbrock heads, Performer RPM manifold, and headers. The problem is the 9.5:1 compression. If anyone knows any way to get 9.5 compression with 390 crank and rods, let me know. All I've been able to come up with is up to 8.5:1, or over 10.3:1. The only way I know of to get 9.5:1 compression is to use 360 rods, 390 pistons (1.680" compression height), and .041" thick head gaskets. The problem with this is that the 360 rods dont like high revs, above 5500rpm (arbritrary number, heard stories about 360 rods giving up around 6000rpm). To further muddy the waters, the Performer RPM manifold ports dont match up well to the stock heads, as the ports are bigger on the intake. So with stock heads, unless you match the intake port to the intake manifold, you're stuck with the regular Performer.

So the solution I've been giving out is to do this:
1. Edelbrock performer intake.
2. Crane 343901 cam for towing, or 941 for more hp
3. 360 rods
4. .041" thick head gaskets
5. 1.680" compression height standard 390 truck pistons
6. Stock heads (360 heads will give you about 9.62:1 compression, 390 heads will give about 9.47:1) Edelbrock heads will let it wind up more and make more power, so watch the revs if you go this route.
7. Get it balanced.

With the stock 360 heads and 941 cam, this setup should be making 333hp @ 4500rpm, and 418 ft-lbs from 2500-3500rpm (it's flat).

Like I say, if someone knows a way to get 9.5:1 compression in a 390 with 390 rods and standard pistons, let me know. I'd be all for it. For now, I'm stuck with recommending 360 rods. Maybe some kind of extra thick head gasket?

 

which headers would you suggest getting? What are the actualy different hp/torque going to be on the different cams anways? I am only 16 and i dont feel like tearing down my engine right away. But....if its the easiest way to get power i guess ill have to. What exactly is the deal with the whole compression thing, im sorry but i dont quite get it.

 

If you use 390 crank,rods and 360 pistons with -10.3cc valve relief's and the .041" felpros you will get 9.46:1 compression.That way you dont have to worry about spinning the motor up too high.

 

-begin Compression 101-

Compression ratio is the amount the air / fuel mixture is compressed before it is ignited. It starts just before the intake valve closes and ends when the piston gets to top dead center. Static compression ratio is the ratio the fuel / air would be compressed if it were compressed from bottom dead center fully to top dead center. If you had an engine with 9.5:1 compression, the swept volume (volume the piston displaces as it moves) would be 9.5 x the compressed volume (the volume above the piston when it is at top dead center). Then to further complicate things we have dynamic compression ratio. This is the compression ratio from the point that the intake valve closes. This is always lower than static compression ratio. This is important when selecting a cam. If you have a high static compression engine and stick too small (short duration) of a cam in it, it will be allowed to build too much compression and the engine will ping and ruin itself. Conversely, if you have a low compression engine and you put too big (high duration) of a cam in it, it wont build enough compression and the engine will be a gas guzzling dog. I selected about the right cams for your application. It might sound like you can up the static compression ratio and use a bigger cam for more power. You can, but you sacrifice low end torque, and the flow through the heads may force more air in at higher rpms creating a higher dynamic compression ratio. It becomes more difficult to select the right cam the higher you go on static compression ratio.

-End compression 101-

This was with a 600cfm carb, I forgot to mention that.

With the stock 360 heads and 901 cam, this setup should be making 315hp @ 4500rpm, and 438 ft-lbs from 2000-2500rpm (it's flat).

I like Hedman headers. Get the ceramic coated ones if you dont want 'em to rust.

I would suggest the book "Rebuilding Big-block Ford Engines" by Steve Christ. It has everything you'll need to know to rebuild your engine, like torque specs and stuff. It's sold in the parts shop button in the upper righthand corner of your screen.

 

That much for valve reliefs? Where are you getting these pistons? I figured 3 cc tops.

 

Thanks so much rusty, i have gained more info in the last 1.5 hrs than i have in a long time, lol.

 

the speed pro and ross. Ledsled and russ are both useing them they are 360 comp height with reliefs cut in them.

 

According to this the valve pockets displace 5cc. Still not enough to get it below 10:1.

 

That is just a blanket info sheet if you call them place an order and customize your pistons then you will have it.

 

I've been trying to get this cr thing answered too. Are there any differences in the heads? I have a set of C8AE-H heads. The rods that came out are C6AE-C but there is nothing on the piston except STD. The pistons so have a dish. What years gave what cr? Did FOrd make a piston without a dish and if so on what? I'm beginning to get mine ready to go back together and really need to figure these things out. I also would like to get in the 9.5:1 area.

 

Not to steal the thread but I am going with .030 over, Speed Pro Hyper. units with a compression height of 1.759 and a dish of .080 and diameter of 3.220, w/ valve reliefs. Heads are rebuilt stock C8AE-H units. Any clue as to compression ratio? I am hoping between 9 and 9.5. Also I am going to a Comp Cam, XE262H, 262 / 270, 513 / 520. I did not replace the "old" springs cuase shop said they were still good. Is this a mistake? If I repalce the springs with new, can I just rebuild the heads, making sure the valves are returned to the position I got them out of? Should have thought of this beforehand but biz has been AWESOME with the correspnding headaches and hours.

Thanks guys, you are the bast source for info, bar none.

 

which book would you guys suggest buying. How to rebuild big block ford by steve christ (i know this was already mentioned but i saw another one) or max preformance ford V-8's on a budjet. I plan on gettin one of these and search through them.

 

Kurt, In my 433 build, I'am Running the TRW/speedpro Forged Pistons..


part # TRW-L2303NF30-CR 10.66 to 1, .041 felpro brings it down to 10.35 to 1....They have an -.085 dish and -10.3 cc Valve Eyebrow...

Part # TRW-L2291F30 - for 390 is 9.91CR with flat top w -10cc eyebrow..

Russ

BTW...For what its worth as far as Ebrock heads go..Every .006" Milled you come up about .1 on CR....I do know of guys looking for that .5 and took off .030 on the heads..But also remember what comes off the head has too come off the side's of the Intake for proper seating and port match..

 

on a 390, here's a formula that works with even 87 octane gas------- flat top replacement pistons ( for 66-70 car applications 10.5 to 1 ratio) Crane 272 degree Energizer cam ( .523 lift/ 272 degree advertised duration with 1.73 rockers) Use your stock D2TE heads, but remove all sharp edges from the chambers , port them to match the Edelbrock intake if you'd like. Stock distributor with a Pertronix unit. Headers ( this is manditory) Carb can be anything from 600 to 750 cfm, depending on your preferences. I'm running this combo in a 68 Monterey with a std bore stock pistoned 390. Sometimes get a little ping with 12 degrees initial timing but never with 89 octane.