New To Me 91 Fox, Looking For Ideas

I've been running an AJE kmember for a few years...no issues. If I were you I'd build the 351....that block will hold more power than the 302. I built a stock block 331 turbo....wish I would've done a 351 to 393 stroker motor. 351 block is good for 750hp vs 500hp. The 393 stroker only needs a stroker crank, rods and pistons are not stroker specific.

Suspension stuff isn't where you want to shave pennies....ya get what ya pay for.

The AJE k member works for me because it keeps the stock geometry and dropped my motor about 1/2 inch. No where near as high tech as maximum motorsports.

Far too many people put a dab of this and a dollop of that, and then wonder why the car doesn't run worth beans. Then they think off the shelf computer chips will fix their mismatched parts problem. It won't

You have to have a plan for what kind of performance you want: Hot street. Street/Strip, Pure strip, Autocross or Road course. Each one requires a different strategy and a different set of components.. Mismatch the components and you’ll have a car that falls flat on its face when you demand performance.

Everyone thinks HP! HP! HP! and thinks that peak HP is what they need. Peak HP is great for a drag strip car when it has the proper gears and tires to get the car up into the high RPM range where it develops that high peak HP near the finish line. On a street car, that strategy will have Honda Accords outrunning you, because you will never get the engine RPMs high enough without running over everything in your path.

Here’ the strategy: Always remember that there are some tradeoffs in any engine combination. Most of us don’t have enough money to “have it all” as if it was possible by some masterful combination of parts and tuning.

The following recommendations are for 5 Speed Manual transmission cars without NO2 or pressurized induction, stock short block.
1.) Hot street: Broad flat torque curve, high velocity airflow in the intake and heads for best throttle response. Gears suitable for reasonable gas mileage and long road trips without excessive engine RPMs. Stand on the gas pedal from a rolling start to squeeze into that gap in traffic in front of you, and it jumps quick and hard to get you there. Max RPM’s are 5200-5500 RPM for best power. Lopey cams may sound cool, but run poorly in a low RPM street environment.
Use stock cam, stock, GT40 or mildly ported stock heads, Cobra or Explorer/GT40 intake, advanced timing, stock 19 lb injectors, stock fuel pump. Use some good 1.6 or 1.7 ratio roller rockers for extra punch. Use a King Cobra clutch, with stock iron or steel billet flywheel. MAF cars can use a 65 MM TB from the Explorer intake manifold and a 70MM MAF from a 94-95 Mustang. Drive train: 3:55 gears with soft tread compound tires. Use some Ford Racing unequal length headers, stock 2 1/4” cat pipe and some mufflers that don’t drone or get too much attention from the law enforcement or neighbors. The stock computer will handle all this with no problems and doesn’t need any help in 90% of the cases. No skinny or grossly undersize tires for the front: remember you still have to stop quickly in traffic. Make sure all the rubber bushings in the front and rear suspensions are in first class shape. Leave the emissions equipment intact and working. Removing or disabling it won’t get you any more HP or performance. Do not convert to carb or remove A/C: either one will reduce the resale value. Carb conversions cannot be titled for street use or get tags in some places. They definitely won’t pass smog inspections.

Street/strip: A little more slope to the torque curve with a gently sloping peak. Use slightly larger port volumes on intake and heads for more peak HP. Uses 3.55 or 3.73 gears to get the RPM’s up into a higher range quicker. Be prepared to sacrifice some low RPM throttle response in exchange for high RPM power. This by necessity will be a Mass Air or Mass Air conversion on 86-88 5.0 Mustangs, since stock speed density will not run well with the changes in engine airflow. Don’t get too crazy on any one engine part since you still have to drive the car on the street, and a mismatch can make street driving miserable.
Use stock or mild aftermarket cam, Ported GT 40, or 165-180 CC port volume aftermarket aluminum heads. Use a Trick Flow, Edelbrock Performer or equal intake manifold. Take a 73 MM aftermarket MAF calibrated for 24 lb injectors, and 24 lb injectors, 155 LPH fuel pump, Kirban adjustable fuel pressure regulator. Be prepared to shell out some $$$ for a custom burned chip using data gathered from a dyno run. Mass market chips will not get the job done. Use some Ford Racing unequal length headers, aftermarket 2 1/2” cat pipe and some mufflers that don’t drone or get too much attention from the law enforcement or neighbors. Drivetrain: expect the stock T5 to fail, so save your money for a super duty 5 speed trans. Tremec 3550, TKO 500 & TKO 600 are the best choices. Different gears in a stock T5 case work for some, but there is only so much power you can pass through a T5 in race mode before it breaks, even with stronger gears. Next are the Chassis mods: full length subframe connectors, different springs, different shocks, aftermarket lower and upper control arms with rubber or urethane bushings. Buy all the parts from someplace like Maximum Motorsports, Griggs or Steeda as a kit so that you know that all the parts fit and don’t argue with each other. Carry spare tires and wheels for the drag strip: skinnys for the front and drag radials for the rear. No skinnys for street driving! Over 85% of the breaking power is generated by the front tires, so skinnys won’t do the job in a panic stop situation. Disconnect the front anti-roll bar at the strip; reconnect it before you drive home. Leave the emissions equipment intact and working. Removing or disabling it won’t get you any more HP or performance. Do not convert to carb or remove A/C: either one will reduce the resale value. Carb conversions cannot be titled for street use or get tags in some places. They definitely won’t pass smog inspections.

Strip only: High RPM, High flow heads (185-215 CC port volume), wild cam, high flow intake manifold, 70 MM or larger TB, 80 MM or lager MAF, strip everything out of the car that doesn’t make it go faster. Carbs are OK if that’s what you want, but remember that as the temp/humidity/ barometric pressure/altitude changes, you have to re-jet and readjust the carb. EFI eliminates most of that with its built in compensation or you can tune of the fly with a high end Motes or Tweecer system combined with a wide band air/fuel ratio meter. Use custom headers, dumps and minimal mufflers. How fast you can go on 5 liters is a function of the skill level of the driver/mechanic and the size of your wallet.

TRAILER the car to the race track since it won’t be legal to drive it on the street. Drag slicks in the rear, skinnys up front, use 3.73 or bigger gears (4.xx) in the rear axle. Since you won’t be driving on long trips, the big gears with work with the high RPM power curve to get the best results. Drivetrain: TKO 500 & TKO 600 are the best choices. Different gears in a stock T5 case work for some, but there is only so much power you can pass through a T5 in race mode before it breaks, even with stronger gears. Next are the Chassis mods: full length subframe connectors, different springs, different shocks, aftermarket lower and upper control arms with rubber or urethane bushings. Buy all the parts from someplace like Maximum Motorsports, Griggs or Steeda as a kit so that you know that all the parts fit and don’t argue with each other. Remove the front sway bar, put an airbag in the rear spring of the side that spins the tire the most. Plan on a roll cage if you are truly serious about going fast: most strips will require it once you get to a certain ET range.

Autocross is a combination of Hot street engine and street strip chassis prep. The engine must accelerate quickly from low RPM and needs a broad, flat torque curve. Next are the Chassis mods: full length subframe connectors, different springs, different shocks, aftermarket lower and upper control arms with rubber or urethane bushings. Buy all the parts from someplace like Maximum Motorsports, Griggs or Steeda as a kit so that you know that all the parts fit and don’t argue with each other. Most of the time you’ll never hit third gear, so some 3.73 or bigger gears (4.xx) may help a lot. You’ll have to spend some more money on brakes since it kills brakes quickly. Rear disks, larger rotors up front, stainless steel brake lines, different brake pads. A 87-88 T Bird Turbo Coupe or SN 95 rear axle will be your best bet. Autocross will severely strain 1st & 2nd gears, so your T5 may take a premature dump. Save your money for a super duty 5 speed trans. Tremec 3550, TKO 500 & TKO 600 are the best choices.

All out road race is the most difficult of all: an engine that will run at high rpm hour after hour and never fail, yet pull hard out of the hairpin turns that will require a lot of torque at lower RPMs. In my opinion, guys that can successfully build a winning road race engine are the cream of the crop. Top this off with a chassis built for strip only duty, but with changes to the settings of springs, tires, roll bars brakes and shocks. It’s a whole other world of racing.
You’ll have to spend lots more money on brakes since it kills brakes quickly. Rear disks, larger rotors up front, stainless steel brake lines, different brake pads. Air ducting to cool the brake rotors will be a must. The brake rotors of cars on a high speed road course glow red after several hard laps of racing. Drivetrain: TKO 500 & TKO 600, and T56 close ratio are the best transmission choices.

Heads do swap from 302 to 351

Get some bolt bushings to adapt the 1/2 bolt holes in the 351 heads to 7/16" and then it is bolt on and go.

The 351 uses a different lower intake manifold since the 351 engine is wider and has a taller block.


Stock heads interchange:
There were only a few years that the 351 had different heads from the 302. Most of those did not have the hardened valve seat inserts or larger valves. That's a trip to the machine shop and money spent $$. You will need to have the valve springs replaced as well to accommodate the cam with more lift. The 351 heads will have a bigger combustion chamber volume which will reduce compression ratio with a stock 302 displacement.

All in all, I would recommend the GT40 heads before any stock 351 heads; they flow better and don't require anything but valve spring replacement. That saves money for other things you will want.

Save your pockets and build a 351....if you have the itch to drive just throw a stock 302 with mild cam together.

I've got 10 grand in my 302 and it probably won't survive until fall. Make the best of this stage while you can.

Look at it this way...the 351 already has 49 cubic inches more than a 302....and the block can hold 250 more horsepower.

You mentioned a 347ci. the 351 already has 4 more cubic inches than that. The lower intake is different but everything else can bolt on. 302 heads would have to be drilled for 1/2 bolts but most aftermarket heads are made for bigger bolts. You'll need a distributor, headers, and the power steering pump bracket from a 351 along with an alternator bracket. Some other minor stuff to get rolling. Do some research.

Don't be like other idiots like me on here. I understand if money is the deciding factor....but 351 is the way to go from the start, man. That block will grow with you....the stock 302 will get outgrown pretty fast now days.

90sickfox said:

Save your pockets and build a 351....if you have the itch to drive just throw a stock 302 with mild cam together.

I've got 10 grand in my 302 and it probably won't survive until fall. Make the best of this stage while you can.

Look at it this way...the 351 already has 49 cubic inches more than a 302....and the block can hold 250 more horsepower.

You mentioned a 347ci. the 351 already has 4 more cubic inches than that. The lower intake is different but everything else can bolt on. 302 heads would have to be drilled for 1/2 bolts but most aftermarket heads are made for bigger bolts. You'll need a distributor, headers, and the power steering pump bracket from a 351 along with an alternator bracket. Some other minor stuff to get rolling. Do some research.

Don't be like other idiots like me on here. I understand if money is the deciding factor....but 351 is the way to go from the start, man. That block will grow with you....the stock 302 will get outgrown pretty fast now days.

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Good advice. We've all been that idiot at one time who threw big money parts into a stock block 302.

I wouldn't say AJE doesn't have issues.
I have an AJE k member and it suffered from issues they knew about and they refused to give me another one. I'm not the only guy to have problems either. Then they lied about shipping me parts to fix the issues, then when I got the parts they didn't fix the problems.

Unless you are a hardcore drag racer, stick to MM for suspension parts.
You will only have to do it once.

If you are into drag racing there are still better companies out there.

With that said, I wouldn't start with a k member, it's a whole lot of money to lose a few lbs.
Cheaper to make more power. If 100lbs is a .1 in the quarter, you may spend $750 to a $1000 to get the same amount of performance as a $75 set of under drive pulley's (not that I like pulley's)

If you decide to pull the engine, do the k member then.

Coil overs will fit without tubular A arms or a k member, so if you want to freshen up those parts, you can.

As for holding out for a 351?
That depends on your finances and how quickly you get things done.
There must has been 1000 guys through here, that wanted 351's, dart blocks, turbo's etc...
What they don't realize is building a car that can make and support that much power is extremely expensive.
The majority of these guys bit off more than they can chew financially, mechanically and or life and priorities changed never to be seen again. So i'm a bit of a skeptic on "building for the future". (it's not personal, I just believe thinking big isn't always the way to go)

So if you have 10 to 20 grand sitting around to dump into your car, yeah wait it out.
If not, do things that will let you enjoy it now and worry about the future, in the future.

A good hci 302 with a mild mannered cam is not only pretty quick, but fun to drive too, at the same time it doesn't destroy the entire drivetrain.

For street with stock E7 heads, I would say to keep the stock intake manifold and get the lower intake ported. Port it yourself or have tmoss do it for you. When I had my old 93' gt aod vert, I installed an explorer intake and I was not too happy with the results. Even though I gained some power from around 3500 rpm to the shift point at 5000 rpm, the car lost power below 3500 rpm. That was comparing to the stock 93' 5.0 untouched intake manifold with oil residue in it. That car had a pro-M 75mm maf and an explorer 65mm throttlebody. Being a street driver with an AOD that had the stock 1800 rpm stall converter, the intake manifold swap made it feel more like a slug even though it would pull hard when you floored it and got the rpms up there. Now, my current setup is the stock intake manifold with a ported lower intake and stock 60mm throttlebody with a 95' mustang 5.0 70mm maf and it feels like it has much more torque throughout the rpm band than my old 93'. Even with the heavy duty clutch fan (my 93' had the taurus electric fan), it feels like it can smoke my old 93'. The exhaust setup might have something to do with it too. My old 93' had a full 2.5 inch exhaust setup with standard 40 series flowmasters and an offroad x pipe. My 91' mustang also has the 2.5 inch offroad X pipe, but it has steeda mufflers which are straight-through design (made by Borla) which are supposed to function better with the X pipe compared to chambered mufflers and I still use the stock 2.25" tail pipes. The stock diameter tail pipes helps to maintain the velocity of the cooled exhaust gasses. That probably helps in making my 91' feel more "torquey". Hope this helps.