Rebuilt 390, Need your help/opinions please……

[Timmy]

I’m looking to replace the 390 that’s currently in my Mach 1 and need everyone’s help/advice. I’m open to all opinions on this topic. I’m looking at $3300 shipped to my door no core charge 12 month 12K warranty. My local shop wants 5K for the same build up with no warranty and no RPM intake.

D&J Machine & Performance Engines located in AZ

400hp, 460 ft lbs of torque at 4000rpm
2-bolt main block casting # C6ME .030 over
3.780" stroke nodular iron crank
6.488" forged rods with ARP rod bolts
Pistons are Forged Speed Pro pistons by Sealed Power 9½ to 1 compression
390 heads, [C1AE or C4AE] Big Port heads with 2.030"Int/1.560"Exh valves and 1.440" high performance springs no port work. They have the 8 bolt ex. pattern
Elgin Pro-Stock cam .536" Int. and .562" ex. valve lift. Advertised Duration is 290 Int. and 292 ex. Duration @ .050" 224 Int. and 234 ex. Ground on a 110 Lobe center.
Double row timing set
High volume oil pump with steel drive shaft and bolt on oil pickup tube
Brass expansion plugs
Edelbrock Performer RPM aluminum intake manifold
This engine comes completely assembled with oil pan, timing cover, harmonic balancer, valve covers, and intake manifold

 

[LMan]

check your PMs

 

[D.Hearne]

If I was you, I'd look at buying a short block built that way. Then have your heads rebuilt. Other wise, you WILL have problems with bolting up your exhaust due to the C1 and C4 head's 8 bolt exhaust pattern. Your heads will have the GT/CJ "dual" pattern exhaust boltup. Plus the edelbrock intake matches your head's intake ports better. Those so called "big port's" really aren't bigger than what you now have. Sure they're "taller" but they're also narrower than the GT390/Medium riser 427 intake port. If you take a close look at that "taller" port, you'll notice that the bottom 1/8-1/4 inch is "wasted space" , the floor jumps up sharply just inside the opening in the head.The GT390 /Medium riser ports are fatter than the C1/C4/CJ ports and thus, the area at the openings are actually a little larger in surface area than the "taller" port.The GT390 head also has smaller combustion chambers for better "quench" and increased compression and with a cam like that you posted, can be run on 87-89 octane gas. Also recommend switching the oil pump to a high pressure unit, not a high volume, the FE's really don't need lots of volume there, and the steel drive and bolt on tube, aren't anything special, that's what Ford put on them from the start. A good heavy duty drive will help though.

 

[Timmy]

LMan, Did you get my PM?

D.Hearne, if I did go with what you suggest and get short block, would it be worth stepping up to Ebrock RPM heads? Do they flow that much better than my stock heads? Also, I've always been told a "high volume" and "high pressure" oil pump were the same just different terminology. Can you clue me in on the truth?

Thanks

 

[D.Hearne]

If the price is OK with you then by all means go with the Edelbrock heads. Just rebuilding yours, could cost upwards of $6-700 if you need new guides, seats, valves, etc. Or they could cost much less, depending on their mileage. Take for instance, the heads on my 68 Merc's 390, after 34 years, but only 60,000 miles, all they needed was new valve seals. Total cost there was $35 labor. As far as the E'brock heads flowing more, they don't flow that much more than stock ones. Even with your stock heads, it's not hard to reach 400hp with that cam you listed. Just a good port/polish job will get you there. Now port a set of E'brocks and you'll probably get another 50 or so horses max.There is a difference between a high pressure and a high volume pump, the high pressure unit will be a std volume unit, but with a higher than stock pressure relief valve. The high volume is just that, more volume, but FE's don't always need more volume, unless you have a loose tolerance or high mileage motor, I wouldn't bother with it. I went with a high pressure unit in the Merc's 390. Works fine. Pressure builds to about 80 lbs cold, and 60-70 lbs hot. The crank is std/std, with new bearings, everything else besides the cam,rings and oil pump & it's drive is still the way Ford built it. With you being located in Conway Ark. , you really should take a drive down to Arkadelphia to talk with Keith Craft at Keith Craft Racing, he's one of the top FE builders in the country, he might be able to build you a better short block than that other company you posted. Plus you'll save on shipping. He can also give you better info on Edelbrocks heads than I can.

 

[D.Hearne]

Timmy- Keith Craft has a website----www.keithcraft.com

 

[Timmy]

Thanks for the explanation on the oil pumps. I'll check keithcraft out and see what they can do.

 

[Timmy]

OK, I’m going with a short block option and Edelbrock RPM heads and intake. The last question I think I have is this. What cam will give me the best performance with least trouble? Should I go with the above Elgin Pro-Stock or with the Edelbrock RPM cam or what? I have to go with adjustable rocker arms with the Edelbrock but don’t know about the Elgin.

I plan on running a Holley 770 Street Avenger with Vac secondarys and stock stall converter (C6 trans).

I have searched my butt off and checked FE forum and forum and opinions on the RPM cam, head and intake combo seem to vary from junk to works great. Thought I would check with you guys and get your opinions.

 

[1320stang]

Tim, if your going with Keith on the short block build, tell him what your plans are and he can recommend the right cam for you. If you think about it, most of us probably haven't tried out as many cams as a good builder has.

 

[Timmy]

Yea, sorry to say, I can’t afford the short block from Keith. 8K is by far outside of my budget. I’m sure it’s worth it. I talked to them directly and they were very nice but I’m sure they would rather answer a “paying customers” questions on cam selection. Their stuff is hard core. He told me they don’t really do anything like I’m looking for.

 

[1320stang]

HUH!?! Their website shows a complete 390 based motor for a tick under 9k. That's a whole motor, not a short block and that's with him supplying everything, short of the intake I believe. But it includes his stage 2 Edelbrock heads.

You might try getting ahold of Rick Kirk in Ripley, OK at RK Machine. Littlehenry<removethis>[email protected] He does FE's and has an amazing collection to boot. Even if you don't get Rick to do your motor, a tour of his facilities is in order.

 

[D.Hearne]

If you're gonna stick with the stock converter, then limit your cam selection to no more than a 280 degree ( advertised duration) cam. Otherwise your motor's not gonna be happy off the line or idling. That Elgin cam, isn't going to work with a stock-stall converter.Neither is the RPM cam.

 

[PoliceInterceptor]

There has been great discussion on the FE-Forum about the RPM cam and converters, IIRC popular opinion was the 3000-3500 was about right.

What they have listed above is basically a stock bottom end with a cam and speed pro pistons. The speed pros are less than 300.00, a nice cam kit (might I suggest the CRANE 343802 (801 as kit)) 200.00.

So, pistons, the cam kit, springs for the cam kit, rings, gaskets, and ARP bolts (for the rods, heads and mains) and you are out around a grand. 300 for the intake, and you've got 2000.00 or so to spend on machine work/head work/ assy.

I think you could have it built locally for less than the E-Bay motor, AND know whats in it.

Take a look at the Blue Thunder Intakes as well. I think they are much nicer than the E-Brock. But they cost more.

Also, if your Mach has a shaker, I don't think the Edelbrock will work as the carb pad is moved back on it.

 

[Max Power]

Sounds pricey for a 390. For the 5k, I would think you could find a 428 rotating assembly and have a 410 stroker for the same money.

I ran a comp cams 280 in a 390 with an edelbrock intake, 750 vacuum Holley and stock stall and it worked really well. Using the stock heads and valvetrain, I used Rhoades lifters and they worked really well. Idled smooth, sounded like a solid cam, and since the stock rockers are a rail bolted into place, I didn't pull my hair out trying to adjust em right.

 

[Timmy]

I’m sorry guys, I don’t know JACK about converters. I’ve always driven sticks. I know what they do but don’t know how to pick the one I need.

1320stang, you’re right. That is for the complete motor. I can’t go 9K and when I talked to them on the phone, they quoted me that engine. No short block quote. They basically told me they don’t do short blocks like I’m looking for.

PI, I am looking to get it built locally. I’m not confident in building the bottom end myself and the local guy said he would give me a 12 month warranty on the bottom end. No shaker so I’m good there.

D. Hearne, What HP can I expect using a cam with 280 degree advanced duration or less. Better than stock?

With a converter stall of 3000-3500, how will that do on the street? That seems high but I don’t know. Is there any guidelines you can point me to in how to pick a converter. Dose anyone know the stall speed of the stock converter in the BB C6?

 

[PoliceInterceptor]

Take a look at:

http://www.tciauto.com/tech_info/torque_converters_explained.htm

I personally wouldn't run a 3500 converter on the street. That RPM cam really likes stall from some previous post. It also has tight lobe separation and a ratty idle, much better chouces in my opinion.

Also, you didn't mention what exhaust you are running, but if its 390 mustang manifolds, you need lots more exhaust duration. The Crane 801 is a good cam for that. Easy to live with.

My new motor is going to run a Lunati 405A1 solid though, so we will see how well it works.

What gears are in this car?

 

[D.Hearne]

Timmy, If you're going with a 9.5 to 1 compression motor, then I've got a good short block to sell. It's a 60 over C7ME-A block, the crank is turned 10/10, and the whole thing probably has less than a thousand miles on it. It doesn't have forged pistons, but stock type dished cast ones. I pulled it from a 63 Merc, a few months ago, and pulled the heads to see what exactly it had in it. The bore's have no wear, the bottom end ( crank and rods) is spotless, none of the usual gunk that builds up after a motor has a few years & miles on it. Put in a good cam, and the Ed. heads, and you'll get 350-375 horses with it. Or Use a set of late 60's C8AE-H heads for a little compression boost for a few more ponies. I'm asking $500 for it, and can meet you halfway for you to pick it up.

 

[Timmy]

I’m not set on the RPM cam but would like to make 400HP (if possible) with the stock bottom end, RPM heads, intake and whatever cam can get me there and still be streetable.

I’m running Hooker Super Comp headers on my stock 390-GT heads. The rear gear is the stock 3.25 with a locker.

I never dreamed cam selection could be so involved.

 

[D.Hearne]

It'll taek the right cam to get 400 horses with a 9.5 to 1 comp ratio. You'lll be looking at a custom grind to do that. Something that will get the dynamic compression up with a 9.5 ratio. Most performance off the shelf cams do just the opposite. And ditto on doing it with a stock converter.

 

[PoliceInterceptor]

I think that the Crane would get you to your goal, or VERY close. I was also told that it would by some folks who know way more about FE's than me. Dyno Sim also puts it at about 400 depending on heads.

Cam selection can get very complicated, as can converter selection. with your 325 gears it will tend to stall on the low side, and you don't want it to stall above your cruise RPM. This effectively limits the stall of converter you can run as well as the cam.