I know you said you’ll check, but don’t assume or trust anything. I had to send a guy back home with a set of 427 medium riser heads because I wouldn’t use them. He torqued up the bolts and pushed out the bolt hole on at least 4 holes. Literally blew out the iron at every hole. A rare set of heads are junk without mag, welding and machine work. They “might” have sealed after the mess, but he wasn’t willing to mag or cut them and no doubt it distorted the sealing surface, so I had to send him away.
I doubt you will have to go far off the stock calibration on the 600, sometimes wide bands can add confusion, The 600s are pretty close, but be sure to be careful during rebuild. Don’t overtighten float bowls, likely good if you have the metering surfaces on the throttle body milled flat, and follow setup to a T.
While it’s apart or over the winter, may want to consider a distributor recurve. It makes all the difference in the world part-throttle, none above about 3000, but daily driving really helps.
Thanks for the input…I won’t be doing the install until March or so. For now I’ll:
Install the Blue Thunder 427MR Intake…double check bolt lengths
Rebuild and install Holley 80457 600 cfm carb I have from years ago. If it doesn’t work well, may purchase and install one of the new Holley Ultra Street Avenger 670 cfm or 0-80783C 650 cfm (more original look) Was thinking fuel injection, but maybe in future.
Install a 180 degree thermostat…believe previous owner has a 160 degree currently installed per service records
Install new plugs, wires, cap…already has a Pertronix Ignitor I installed…I already installed a relay to provide 12v+…previous shop had power from stock resistor wire connection.
Checking timing curve. I don’t believe this is the stock distributor based on paperwork…may purchase a new aftermarket unit with adjustable vacuum and ability to change springs.
Currently has 428CJ exhaust manifolds installed. I have to double check the head number to see if stock heads are installed. I would like headers, but don’t know if I have patience to install and don’t want the power steering adapter.
Not sure why everyone is so against the PS adapter though. I have installed likely 30 of them, and I did my own car in 1997 or 1998, literally have never touched it or any other one. The key is to make sure it’s bolted tight, but any component should be.
Personally, I just want a set that doesn’t utilize as much space, simplify installation, and just looks a bit cleaner on install…thus the shorties.
I have a call into the JBA Custom Shop to check on availability and cost as no one else seems to build them. I am also considering the Borgesen power upgrade in a few years.
If that doesn’t work out, may just keep the existing 428CJ manifolds that are on it, or bite the bullet on long tubes if I can find local assistance for the install. This is a few years out anyways for me.
I thought CJ manifolds were supposed to be one of the big improvements you could do on a 390. Are headers really gonna be that big an improvement for all the other headaches they will cause?
Sorry, this one turned into a book and drifted to exhaust discussion
Fair enough, I run Hooker 6114 in most of the street builds, they do fit well, and can be installed on the engine before you swing in, as can FPAs. The issue with headers is that you have to match your exhaust port, if you are currently running 390 heads, C7AE-A, C8AE-H, even with the bolt holes corrected, the port won’t seal well. FPA does sell multiple flanges, but if you upgrade to a deep breathing head later, it won’t match later. It’s about .230 lower on a 390 unibody head compared to a CJ, Edelbrock, etc A custom shortie could be nice, but likely won’t be cheap, be sure to ceramic coat any header in a unibody car for heat control
Certainly an improvement, but it’s incremental. If I had to estimate, on a 400 HP engine, I’d say +10 HP with CJ manifolds, and +35 (total) with good headers, assuming both had the proper exhaust system to do it. Less of an issue of flow as much as influence of the primary tube and collector to actually pull more air/fuel in during overlap. The more power you make, the more overlap you have, etc, the more the gap will extend. I think Royce may have been part of Jay Brown’s exhaust testing, he certainly was a part of intake testing.
Don’t want to go full engine geek, but many have referred to it as the 5th cycle. Suck, squeeze, bang blow, but then there is actually another “suck” when the negative pulse of the last event pulls on the chamber, which pulls on the intake port during overlap. Manifolds, other Ford cast iron headers possibly, just don’t do that because the shape and length of the manifold
It’s ironic the idea of headaches with headers too. Just my opinion, but in all the headers I have installed, there literally have been none that cause me issues other than potentially initial install fitment of cheap ones (having to dimple a tube, etc). In fact, in the F100 world, headers often work better than manifolds over time
What I see regularly is people will painstakingly install every part, using torque values, procedures, etc. Then it will get tight on a header or someone won’t have a wrench and they will overtighten another and leave one sort of loose, etc.
Here is my procedure for headers
1 - Make header, gaskets and heads all have the correct design.
2 - Chase all the threads on an old head
3 - Use 6 point bolts, not 12 so you can use an open end wrench when needed during install, bolt lengths should use most of upper hole depth and as much as you can of bottom but watch for bottoming
4 - Mustang/Cougar - Install on the engine stand before (although you can do in the car as well), lube every bolt with antiseize.
5 - Tighten evenly, like a head bolt, if you need multiple wrenches, find them, use 1/4 drive sockets or thin walls, etc. (The first one you do is a pain, but then you have them). Don’t worry about torque per se, but make them tight, in even steps, and real tight
5 - Swing the assembly in if not done in the car
6 - Get the car running and shut it down, put gloves on, and tighten them all again engine warm. I do this right after flat tappet break in, or if roller cam, after the first fire and basic tune (timing, idle speed, etc)
7 - Walk away for potentially a decade or more, no kidding
Is it more work than to bolt a manifold on with a 35-40 ft lb torque wrench, sure…but the gains are probably the biggest of any bolt on with an FE, so for a stocker, maybe not worth it, but for anything you are building to make power, it’s likely worth more than anything else you could bolt on without big displacement changes
In reality, people need to temper reality into what they would really like. I’m coming from a 2013 Mustang GT with 609 rwhp (I installed a VMP supercharger myself) that was extremely fun to drive in Colorado, and was quick at the drag strip. The Cougar will never run/drive like my supercharged Coyote, but that’s ok…this era of Cougar is a different type of car, but nice in its own way.
I have to limit my upgrades to bolt ons in my garage on my stock 390…don’t have a lift / hoist to make things easier. If I ever decide to pull the motor down the road, I will make the major internal changes then (better heads, cam, stroke it, etc.), but still look stock on the outside.
Thanks for the updates on ports and such…read about that on other forums (vintage mustangs, fepower.net)…something to consider. I have to double check my existing heads to see if they are the stock heads or if the previous owner swapped those as well when it was rebuilt in 2008.
For me, appears I will just move forward with the Blue Thunder intake / carb upgrade and keep the 428CJ manifolds for a reasonable power boost. Will still explore the shortie headers (depending on cost), or wait on the long tubes if I ever pull the motor for a major upgrade (via one of the reputable FE engine builders).
At this stage for the next few years, just want good drivability.
