For me, if it was that original I wouldn't mess with it, especially if you are going to get into it in a couple years.  I'd get the carb and timing dialed in….

That was my thought for now regarding carb and timing…just getting it dialed in for now.  I may send the carb out to Air Fuel Spark for a quality rebuild, and distributor our for recurve.

I’m just gathering ideas in the event I want or need to do a quality rebuild in 1-2 yrs, and start gathering some parts.

Once the car arrives, I’ll have a better idea in how the current power level works for me.  I’m in Colorado at around 5700’ and will lose power.  I will have to tweak the carb a bit, and will pull the distributor and have it rebuilt/recurved if needed.

FYI-this a 56k mile engine and has never been pulled apart, but I trust the seller in being a well running engine. I went into this purchase thinking I may have to freshen the motor at some point (leaks, non-hardened valve seats) simply due to age, and while in there, make some changes to boost power a bit.

I know costs can quickly escalate as changes are made, but will work that with an  engine builder I will need to find for a good “bang for the buck” configuration…thus reason to temper my expectations.  Stroking to 445 is a consideration, but will need to see how that impacts costs.

Ive had variety of cars over time (2013 Mustang with 607 rwhp, 62 Galaxy with the 406/405hp motor, and a 71 Mach 1 with 351C-4V) and enjoyed their power, but know I won’t drive this car in the same manner as those.

After thinking about this for a bit, I’m tempted on using the FPA headers but understand I need to determine if I’m keeping stock heads, or migrate to the 428 heads while keeping existing thermactor system.  I’m hesitant on installing headers now due to fear of breaking exhaust bolts and would probably wait until engine build.

Thanks for the groups input.

Stangman,

I think you expressed it better than I did…a good reliable motor with a little more bite.  The options Brent mentioned appear to fit the bill.

I was originally looking at the PI intake as it appears to have the same PCV setup with a similar balance tube.

If it wasn’t for the originality of this car, I’d do more and splurge on better heads and install the FPA headers.  When opening the hood, Id like it to look stock. 

Cheers,

I'm picking up a stock 68 S code 390 Mustang, and planned to keep the stock heads with thermactor pump and exhaust to maintain the external looking originality, but CJ exhaust manifolds may be an option.  I know this dramatically limits options and potential HP increase.  I wanted the BT intake to help drop some weight off front end, but it appears it doesn't have the correct ports to maintain the original PCV balance tube system.

This would be primarily a car for cruising and car shows due to its originality, but would like a bit more power (who doesn't).  I'm just gaining some input before working with someone on the rebuild in 1-2 years.

With those limitations, can I gain much in power (cam, head port?, etc.) in the event I do a future rebuild?  I assume I'd be lucky to pick up another 50hp.

I'm open to swapping better aluminum heads and installing the CJ style headers if it was as simple as replacing parts.   From my understanding, it isn't that simple as I would then have to work other issues like pushrod length and other measurements...areas where I'm not skilled / lack experience.  My main reason for sticking with the C8AE-H heads is I (in theory) wouldn't have to worry about those things...but probably not cost effective by the time I paid a shop to port.

As I mentioned earlier, I'm hesitant doing headers now with the current GT style heads, and then have to pay for another CJ set later on if I go with better build using aluminum heads.  If I was never going to install better heads in the future, then it wouldnt matter, but want to leave the option open for now.

Members here have already hit the nail on the head...I have to figure out what I want.  This is probably a common problem where folks with these cars are going to be primarily cruisers with an occasional throttle blast...we all want as much HP as we can, but would probably live with a more modest build (425-450 hp) which is still respectable.

frnkeore pointed out the slippery slope perspective in opening up the engine which I'm trying to avoid to some degree.   If I went with pulling the heads, then Id probably prefer to do this once and put on a good set.

Thanks...I appreciate the constructive feedback.   Looking forward to tackling the things I can do myself, but see myself working up towards a modest quality build in the future.

Quote from: My427stang on August 21, 2021, 09:30:00 AM

I think headers are beneficial and should be done during the intake swap for a couple of reasons

1 - Pull the heads and replace valve seals.  With some smart shopping you can put a viton seal on the stock guide.
2 - You can fix any broken bolt easily and make sure exhaust flanges and gaskets match on the bench
3 - You can likely set the headers in before the heads
4 - The headers will make the other parts work significantly better

Then once the heads are back on, finish the intake install.

Of course you could ignore the manifolds, but if you go to do it later, I'd expect you'd have to do it all over, and/or pull the engine.

On a '68 Cougar if I had to pull the heads I think I'd pull the engine. Not saying cannot be done in the car, but is a bit of a PITA! Of course swapping intakes is n fun either.  the factory shop manual tells you to use a hoist to lift the intake manifold which I can understand as it is what 80 lbs?  Headers are best, but if he is not looking to get into a whole rebuild/remake project and it is running good, just swap the intake/carb. The CJ manifold are not as good as headers, but are decent and headers can be a pain. OP has not stated a goal so guess just wants a bit better performance.

At this time, I have two goals....near term and long term:

- Near term - Some are purely aesthetics I wanted to dress it up a little with an aluminum intake (cars and coffee, etc.), while also dropping a bit of weight from the front end.  I also wanted to bump the power a bit to give it a bit more acceleration when wanted.  The Denver altitude has already taken some of that power away, and would like to address that.  The car is primarily just used for fun at this time...haven't really had a chance to drive it too much due to work and such.  Since the engine runs well, I'm trying to see if the intake/carb/distributor, and maybe headers is simply enough at this stage.  The car has 2.73s at this time...was thinking of going to 3.25 as I want to still drive it on the interstate out here....70-75 mph seems to be the min sustained speed I need and didn't want the revs too high on those drives.

- Long term - That depends on how the other efforts work out and if I'm satisfied with the power level for simply driving around in town / interstate, and the yearly blast down the dragstrip.  I'm not expecting a competitive drag car, but would like one that is respectable...low 13's here in Denver.  My427stang has provided me advice for some of this.  I would love to jump on a mild 445 with 500+ HP, but as the engine runs well and the associated costs hold me back at that.  However, if the engine was to take a dump, I would like to do more than a simple rebuild as I only want to do it once.

My current storage / working environment for this Cougar is fairly limited at this stage, so I don't really want to do anything where the car is blown apart for more than a week or two.  This is another reason I'm keeping the current changes somewhat small.  If I ever had to pull the engine, I would have to find one of the DIY garages around here...can't do it at my house as I have the normal family cars to keep in the garage...damn Denver hail.

I am fairly good in being able to remove/install stuff, but would probably rely on an engine shop for heads and engine mods. 

I came from a 2013 Mustang GT with TVS style supercharger....609 RWHP.   That car was extremely fun to drive, but I'm not expecting that level of performance.  I had to make the adjustment in how the cars drive.

If I was to install headers, I was hoping to have enough room by jacking up the engine via the oil pan....I recognize pulling the engine / heads may be the best option though.  I am a but concerned if I buy the headers with the CJ flanges (assuming my heads have been modified - will check to see if all bolts are in) only to find out they don't seal well on the lower port.  Isn't the only true fix a new set of heads with the right configuration as I can't go back back to a regular 390 header (assuming my heads are modified)?

I was tempted to buy a new set of heads and cam and install while in the car, but have read somewhere that the heads should be gone through and rechecked.  If that was the case, then I was probably back to letting a professional go through it and doing it correctly the first time.

So I seem to be in a catch 22...going ahead with the just the intake/carb/distributor or just leave it alone (as engine runs well) and save up the funds to perform a decent upgrade that involves pulling the motor.

Thanks for the info. 

Car currently has a 2.25” dual exhaust and 428CJ exhaust manifolds from the original owner during an engine refresh back in 2008.

@My427stang…now considering the header change based on what you’ve mentioned before.  I have to checkout the existing manifolds to see if the heads were modified to accept all of the CJ exhausts bolts, or if they simply left a few bolts out.  I need to double check the existing head casting numbers to see if the are the C8AE-H heads (which I believe would be stock) or if they were swapped as well with true CJ heads.  If I’m able go big down the road with a nice build, I only want to buy headers once…assume ones with the CJ pattern.