[xr7man88]

Finally got my 390 back home after being rebuilt and dyno tuned. I will be driving this car on the street so wasn't looking for anything too wild.. But I must say it made less power than what I thought it was going too. Anyways I thought I'd share my build as it is kind of the average mans build. Here is my build list.

-1969 390 block (original to car) bored .030 over
-stock heads, mild porting, 428 valves, hardened seats ect
-speed pro h395p hypereutectic pistons
-edelbrock performer rpm intake manifold
-Holley 750 cfm carb
-jba tri y stainless steel headers
-comp cams hydraulic roller cam 33-432-9
282/288 duration, 230/236 at 50, Cam Style:Hydraulic roller tappet
Basic Operating RPM Range:2,200-5,800
Intake Duration at 050 inch Lift:230
Exhaust Duration at 050 inch Lift:236
Duration at 050 inch Lift:230 int./236 exh.
Advertised Intake Duration:282
Advertised Exhaust Duration:288
Advertised Duration:282 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.521 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.532 in.
Valve Lift with Factory Rocker Arm Ratio:0.521 int./0.532 exh.
Lobe Separation (degrees):110
Camshaft Gear Attachment:1-bolt
Computer-Controlled Compatible:No
Grind Number:XR 280HR

Anyways... With that setup it ran with 36 degrees total timing and made 320hp and 380 ft pounds of torque. Peak hp at 5000 rpms. Had a nice torque curve as well. Will be running behind a c6 auto. Anyways please share your thoughts

 

[67coupe393C]

The intake is not helping you at all, put a performer RPM on it for a few more HP and a bunch more torque.
Edit for
Sorry, I didn't catch that you already have the RPM.

 

[Ringo]

320 horse does sound low. What do you have for rear end gears? A set of 3.73's will help out quite a bit without winding things too hard on the street.

 

[66kcar]

CR?

 

[gregb]

I agree that's kinda low sounding for those build specs. The stock heads are not helping, but even so I would have guessed 370-400HP. Depending on the port job. Who built the engine? Degree the cam? What springs are you using with that cam? I'm not familiar with those pistons, what kind of compression are they supposed to give?

 

[McKnight77]

Are those numbers corrected for elevation?

 

[xr7man88]

I live in northern Illinois so elevation is a non issue. The cam was degreed. We were shooting for near stock compression of 10:5:1. The cam specs reccomended a minimum compression of 9:1. These pistons are pretty commonly used for mild 390 builds.

 

[Woodchuck]

IMHO, you should be making more than that too. I'd be looking at whether the lifter preload is too much and/or the valve timing is retarded. What did Comp specify for installation?

 

[happystang]

Is your carb a mechanical or vacuum secondaries? Did you verify that the secondaries are opening? What secondary spring if a vacuum?

What was the AFR?

 

[fastlaneinnovationsllc]

What RPM was peak torque? Do you have the valve springs for a roller can, and is the installed height correct? What headers did they use on the dyno? Are you sure the header ports match the heads? Some FE heads have different ports and there can be about a 1/4" mismatch.

 

[gregb]

Somethings not adding up IMO. Lots of good questions to be checked. Just out of curiosity have you done a compression check? I know it's a new engine, would like to know what kind of reading your getting. I found some specs for those pistons, I'd guess they have about 9.5:1 in your build, which should be plenty.

This is on an engine dyno yes? Not a chassis dyno?

 

[sportsroof69]

Are you SURE it's 10.5:1?

 

[josh perkins]

What is your ignition timing. You can loose 15 hp easy with incorrect timing.

With the distributor vac disconnected, tell us timing at idle and the amount of max timing and the rpm at which it reaches max timing.

Try this simple test. Disconnect the dist vac, loosen distributor bolt slightly, hold rpm at around 2000 and advance the distributor a little. Of the rpm goes up noticeably and it still runs good then your timing is too low.

 

[Huskinhano]

I'm no expert but my off hand thoughts are those are numbers I think a mild 351W with that cam would make. An engine with about 40 more cubes makes me think there is a air flow restriction some place. I really don't know too much about FE heads in general. Maybe stock 390 heads are really that bad even with a little port work or the shop really screwed something up.

I think a mild 331 would make those numbers.

 

[Huskinhano]

I'm no expert but my off hand thoughts are those are numbers I think a mild 351W with that cam would make. An engine with about 40 more cubes makes me think there is a air flow restriction some place. I really don't know too much about FE heads in general. Maybe stock 390 heads are really that bad even with a little port work or the shop really screwed something up.

I think a mild 331 would make those numbers.

 

[Two 68s]

I think its the heads personally. Here is my build:

Edelbrock Performer RPM Intake
Edelbrock Performer RPM Heads
Cam specs:
.226I / .234E duration
.540I / .560E lift
109 deg LS
10:1
FPA headers

We haven't tested it yet, but the guys on the FEPower forum figured it would come in around 420 hp / 450 ft-lbs

You might want to head over there and ask some questions. Very knowledgeable group about all things FE. But again, my guess is your heads are holding you back significantly.

 

[xr7man88]

My dyno read out shows rpm range from 3500-5000 rpms. It already was making peak torque of 380 by 3500 rpms. Torque had fallen to 336 by 5000 rpms. Air fuel ration ranged between 11.4 and 12.4. There may be a few more hp after 5000 rpms but probably not too many. The dyno shop used my JBA headers while dynotuning the engine. Again initial timing is set at 10 degrees with 36 total. I'm using the stock distributor with electronic point conversion.

I really am no expert so I'm not too sure where to go from here. We have the engine in the car but still need to get everything hooked up and install the transmission. Everything on the build is basically new minus the carb which was rebuilt... Maybe I will investigate that first. Not really sure where I can take it to be looked at but I do feel like it should be making more.

 

[jdub]

I haven't seen too many high horsepower FE engines outside of magazines. Too many people think the displacement will carry them. They seem to go really conservative, then they are surprised when a mild 390 at 5000rpms can't beat a wild 347 at 6500rpms. I think Two 68's has the right idea. Same principal applies to most Ford V8s. If you build something that makes peak power at 4000-5000rpms the power is going to be disappointing in a numerical sense (your engine still might be fun as hell to drive...). Ford V8s want to rev. In the 1960s the hot 427s made 400hp+ at 7000rpms from the factory.

 

[LSG]

compression is too low, you don't really have 10.5

XR, my guess is that you compression is too low. You may not have the ten -five that you intended. The H 395P is a good piston, but it was really intended for a 360. The reason that that is a problem is that they are only 1.759 tall, and the rods are 6.488, and the cranks is 1.892, so you have a total of 10.139----and the block is 10.17. So your pistons are .031 down the hole, that doesn't help. Then , I'll presume your engine was assembled with FelPro blue head gaskets, which are about .043 thick when compressed, instead of the .016 steel shim your engine came with from the factory. Those things will make a HUGE difference in your compression. You can have the deck shaved on the block, or you can mill the heads, or you could have had the crank ground for a little extra stroke to compensate.

When your heads were done, were the bowls blended to match the larger valves ? Did the shop fix the FEs well known oiling issue ? The fix is not hard, but I have never seen a shop do it unless they were a Ford or FE specialty place. Even some of them don't know. LSG

 

[xr7man88]

Shortly after writing my first post above I got the car to the shop to get a 2.5" exhaust fabbed up with magnaflow mufflers along with a 3.5 rear gear and a Detroit truetrac rear end. Long story short on the way back from the shop the engine failed (two spun rod bearings) It was awful to have to pull everything back out but the engine builder stood behind his work considering the engine only had about 4-5 street miles on it after the dyno. Upon tear down it was discovered the top end overoiled due to using the incorrect style pushrods (oil through) based on the cam manufacturers recommendation which ultimately caused lack of lubrication on the bottom end.

My builder is great and took care of it. He decided to do more port work to the heads while he had the engine specifically on the exhaust ports. This time around on the dyno with all the same parts the only difference being the additional port work it made 380hp! Nearly 60+hp over the original dyno. Now just gotta get that beast back into the car!