First Car, First Post

Corbin White · Aug 21, 2014

My names Corbin I'm 17 and new to the forums. I bought my first car recently, a 1977 cobra II, after driving my step fathers 89 trans am for a while. Unfortunately I wasn't impressed with this car but I'm not gonna give up. I want to do a swap on the mustang. I was wondering what it is about these 302's that makes them perform worse than others? And if simply getting a different year 302 would make up for some of the performance. I was hoping for something to give me that thrill I felt when driving the Pontiac that I can call mine. Thank you for all the help and I hope this build goes well!

Gearbanger 101 · Aug 21, 2014

Hello Corbin, welcome to the site.

If your current engine is tired and you plan on doing a swap anyway, your absolute best bang for the buck would be to scavenge the junk yards for a '95-'01 Explorer 5.0L engine.

These were roller blocks which utilized a freer revving, hydraulic roller valve train and the much more sought after GT40/GT40X ('97-up) cylinder heads.

Pick yourself up a decent '86-up HO, or better camshaft (B303, E303 TFS 1, etc) at a local swap meet for about $100, spend another $100 on a set of upgraded valve springs here, add an Edelbrock Performer intake and 600+CFM carb, a few odds and ends and go racing!!!

Don't be surprised if you pick up 100hp over what that II made stock (140ish horsepower).

The later engines are more desirable mostly because of their more efficient, higher performance roller valve train and one piece rear main seal, which is less prone to leakage. They also utilize a 50oz imbalance, compared to the 28oz imbalance that your early 302 does.

You might have to mix and match a few front end accessory parts, and I'm not 100% certain of the configuration of your II. Keep in mind that the later roller blocks utilize a reverse rotation water pump.

In any case, you should just about be able to completely put this engine in your car with junk yard parts. The intake, carb and valve springs being the only after market additions.

Smoother running, better on fuel, cleaner running, vastly more powerful and considerably more reliable....it's a win-win all the way around.

Corbin White · Aug 21, 2014

Thank you! So it's not so much as I need to go bigger as it is I need to go newer. I thought something was funny because my step fathers trans am 5.0 with a 4 speed threw you in the seat and I expected this to come a little closer. Luckily My parents own a repair shop so I have access to everything I need

Gearbanger 101 · Aug 21, 2014

You don't "have to" go newer, but the later long blocks do have their advantages.

The big issue with your '77 is that it was built during the fuel crisis era. A time when the North American Auto manufacturers thought we'd run out of fuel in a very short time and their answer was to put the muscle on the shelf in favour of more economical, emissions compliance power plants. Fuel economy literally took precedent over performance. Your poor 302 is so choked down with emmisions garbage, it probably has trouble getting out of it's own way.

You could simply swap out the heads, cam and intake in order to jump up the performance, but I assumed the engine was tired and in need of a freshening up anyway. Besides, with the amount of labour involved, you may as well just swap out the entire long block with a more modern one and save yourself the headache.

I picked up the Explorer long block (intake to oil pan) for my car when I did my build for $300. If you were to do the same, I'll bet anything you could sell the stock Explorer intake to an EFI guy for about what it would cost you to pick up a nice used Edlebrock Performer.

Like I said though, you don't have to change the entire engine....just that there are plenty of advantages to doing so.

....and you should have any trouble putting your uncles Trans Am in your rear view mirror with the power to weight ratio you'll have afterwards.

Corbin White · Aug 21, 2014

I understand now. I'll be going to the junkyard on my next free day to get this thing started.

Gearbanger 101 · Aug 21, 2014

For the sake of argument, I'd look for a '95-early-'97 engine with the standard GT40 heads. The later engines had the GT40P castings, which although slightly better performing, put the spark plugs at an odd angle that often required a different header configuration to correct. Since I'm not overly familiar with what's available for the Mustang II as far as aftermarket headers, I'd try to stick with the stock configuration for simplicity sake.

The Big Blue · Aug 21, 2014

Welcome and you just got some very good advice from Gearbanger, like he said the original II V8 was choked out with pollution controls that really didn't work and where of a lower compression and only a 2 barrel carb to make them better on gas milage, but yes if you upgrade that motor or replace it with a better 302 you will have little screamer there, I'm working on swapping out a 4 banger for a 302 in my 78 coupe now, the good thing about your car is that its a 302 now, there are a few parts that were only made for the Mustang II V8 models that you either need, or have to modify other part to make work, to put a 302 in one, sense yours is a 302 you already have them, so if you do a swap to a newer motor you will need to use your motor mounts of course, you will need your oil pan, its different from all the other fords, I had to modify an aftermarket to fit mine as I didn't have a II pan, and you most assuredly need to use your bell housing and flexplate/flywheel, they are also different from any other Ford, however if you get a newer motor it could likely be a 50 oz imbalance engine, and yours is a 28 oz imbalance, you can have the flexplate/flywheel re balanced to a 50 oz and that should work well for you, but don't even try to use the 28 oz on a 50 oz motor without rebalancing it, I had massage my firewall with a hammer to make a different bellhousing work on mine.
So what I would tell you is to read all the stuff on this forum about doing the swap before you start, and it should go well for you

Corbin White · Aug 21, 2014

I saw that air pump on there, diluting emissions isn't the same as lowering them ford! I'll definitely spend a lot of time reading the forums here during this project. Thanks guys

The Big Blue · Aug 22, 2014

Don't blame Ford LOL, I think they all had them, but I totally agree with you, 1 oz pollution and 1 oz air is itll 1 oz pollution LOL

Gearbanger 101 · Aug 22, 2014

The Big Blue said:
Don't blame Ford LOL, I think they all had them, but I totally agree with you, 1 oz pollution and 1 oz air is itll 1 oz pollution LOL

Wellllll, it's not quite that simple. The addition of air to the exhaust stream allows the catalytic converters to do their job more efficiently and also increases their life span. Adding air to the exhaust stream through the thermactor ports introduces more oxygen to the exhaust mix, allowing the remnants of the spent mixture to burn off more completely.

Believe it or not, pumping air into the exhaust after the manifolds can actually improve performance to some small degree by creating a small scavenging effect to aid in drawing out spent exhaust fumes.

I can't speak for the efficiency of the mid/late-70's smog systems, but the later Fox body systems only consumed about 3-4 horsepower under their most strenuous operation. The system vents to the atmosphere and shuts off under spirited driving conditions.

When Ford went to the OBD II ECU'S and more efficient head/intake combinations later on, they were able to take better control over the air/fuel settings allowing them to run leaner fuel tables, doing away with the air pumps altogether.

The real killer with your engine is the restrictive intake manifold and early EGR set up, low compression domed piston and the tiny valve/closed combustion chamber, restrictive port design of the early head castings.

The Big Blue · Aug 23, 2014

lets see some pics of your new car

Corbin White · Aug 23, 2014

All I have on this phone are pics of the donor car I got the motor from (new phone). I'll get some pics when I'm not busy with school, work, and football. Probably this weekend.

Corbin White · Aug 23, 2014

I will say this, I'm glad I didn't spend any money on the motor from the second cobra II. I'd be devastated. But I got my ford explorer 5.0 today, $225 with a 45 dollar core I probably won't do. As I was hunting through the yard I saw Superchargers there were only 95$. Would I still be able to us a regular HO cam and upgraded springs with a SC? I know I'll need to convert to a blow through carb but mustangs unlimited has different cams for turbo/supercharged cars.

Gearbanger 101 · Aug 23, 2014

Baby steps grasshopper.

Swapping a junkyard engine into your car could be done for well under $1,000. A custome turbo or supercharged application is going to cost you 5-10 times that.

As it sits, you're already going to be adding about 100hp to the cars current output. Get that dialed in first. The superchargers you were probably seeing were the early Gen II and Gen III Eatons from a variety of Supercoupe Thunderbirds, Grand Prix GTP, etc. The supercharger itself is only a small part of that equation. Trying to bolt one of those to a 302 for most isn't cost effective, so don't get too far ahead of yourself just yet.

If you haven't already gotten one, you'll need to source an HO cam from an '85-'95 Mustang GT. The stock Explorer cam is not of the "HO" variety. Shouldn't be hard to pick one up though. $50 would probably get one in any number of classifieds. Or, you could hold out for something with a little broader power curve.

The springs I linked you to are good for .550-.600 lift if I'm not mistaken. That'll be more than adequate for any cam you'd consider using in that engine. There are many choices out there, but don't go too overboard. Remember, the stock style pistons will limit the amount of lift you'll be able to utilize.

Corbin White · Aug 23, 2014

Just a question, although I do know a few welders who might make a supercharger possible in the future. My real question is IF I do go that route in the future would I have to get another cam? Because I don't want to be swapping cams here and then doing it again in about a year. But I will worry about that when the time comes

Gearbanger 101 · Aug 23, 2014

The stock HO cam works well with most supercharged applications, if that's the question you're asking.

Corbin White · Aug 23, 2014

Perfect. Thank you for all the info so far. I am loving this forum and I've been reading a lot of the posts on here

LILCBRA · Aug 24, 2014

Hi Corbin and welcome to the forums!

All good advice so far, just wanted to add my 2 cents.

If I was swapping engines in my car and had the Explorer engine already, I would look into getting a CPU and injection harness and install the fuel injected engine in it. It requires a little more work when installing it, but I think I would be happier with it in the end. No fiddling with the carb, A/F ratio should always be pretty good, a little more reliable, and with the Explorer engine you already have the best of what Ford had to offer the 302 for induction-except the cam. Also, one snag that a lot of II owners face is the exhaust. You may be alright with the stock manifolds to get it running, but good fitting headers will be a challenge. One other if, and it's a big one, if you can find a II with a V6, check the axle tag. You may get lucky and find an 8 inch with 3.55 gears. IF you do, my advice is to get the center section and swap it into your II. It is pretty straight forward and you will get a little extra grunt when taking off. And as Big Blue already asked, pics are always welcomed!

Corbin White · Aug 24, 2014

I've never had a fuel injected car before, I've had an '82 pick up and an '87 quigley 4x4 van. The pros are definitely worth it so I will look into it. And as far as headers I was thinking of using the original explorer header plate and welding my own equal length primaries and collector to them. I have an exhaust bender in my shop so it'd be interesting to try

Gearbanger 101 · Aug 24, 2014

If I remember correctly, getting around the steering shaft was the big hurdle for headers on these cars?

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