Supercharging a Ford 300

I am thinking about supercharging my daily driver 300. The current setup is as goes, 300 inline 6 stock compression, pistons, crank, comp 268 cam, ported and polished head with screw in rocker studs, stock rockers, comp cams hydraulic lifters, stock push-rods, offy dual port intake, heddman headers, summit 650 cfm carb, stock duraspark 2 ignition, and stock oil pump. I'm new to the supercharging thing and need to know what I will need, what supercharger, how to plumb it, if it will run with my current setup, what will work with 87 octane gas, and basically anything else that I can't thing of that I might need.\
I've had the taste of power and I want more, so I thought, put a blower whine under the hood!! :mrgreen:
Thanks, John

You'll probably need a cam with a wider lobe separation angle. How much boost are you considering.

I have no idea really. An amount with an increase in power worth the cost, but nothing crazy that I can't drive back and for to school every morning. What do you recommend, like I said I'm knew to this supercharger stuff.
Thanks for the reply

I dont think you can run much more than 6 psi on 87 octane without running into serious knock issues. If you have access to e85 or want to run meth injection then you could run much more but that sounds a bit outside your scope.

6 psi should provide about a 50-75hp boost and even more torque, noticeable and fairly safe for a daily driver.

The 6 psi sounds pretty good. what all would I need?

To get an idea of what's involved Search for posts by "the last F100" he built a supercharged 300 a couple years back. Good luck

I can't help you too much with you setup being carb'd and supercharged. I'm mostly an EFI and turbo kinda guy but aside from tuning (a huge part by the way) and the actual supercharger itself, you'll need:
Wideband O2 Sensor (Innovate, AEM, etc.)
Boost Guage
Some way of controlling timing (MSD or something equivalent)
Knock Sensor (preferably that ties in to your timing control to retard timing when knock is detected)

Then some highly recommened by not necessary stuff like:
Oil Pressure Gauge
Fuel Pressure Gauge
Intercooler (If possible)

Thats all assuming the motor is in good condition. 6psi on a strong 300 is nothing, the motor, if tuned properly, should still run well over 100K miles like that.

MECH_E":3k30ings said:

I dont think you can run much more than 6 psi on 87 octane without running into serious knock issues. If you have access to e85 or want to run meth injection then you could run much more but that sounds a bit outside your scope.
6 psi should provide about a 50-75hp boost and even more torque, noticeable and fairly safe for a daily driver.

Click to expand...

80ford100":3k30ings said:

The 6 psi sounds pretty good. what all would I need?

Click to expand...

I like the 6 psi idea with one exception.
piston skirts will end up in the oil pan.

Everyone that trys a turbo/blower says "a little more won't hurt" Then they find out just how much or what it hurts.

An acquaintance I knew 30 years ago had a 6-71 blower on a BBC. Since it was a Street car blower was 10% underdriven.
He swapped the blower drive pulleys making it 10% Overdriven. It then Shattered the rings on 2 cylinders.


You could reevaluate your cam pick as well.

There are always examples of people running 20psi with no problems and then someone runs 5psi and sends a rod through the block or blows ring lands. I just provide my opinion on what he may need if he decides to do so.

Anytime you run boost, knock should be your #1 enemy. Avoid it and your chances for success increase greatly. Not saying that avoiding knock alone will grant you invincibility, but its the best place to start.

Granted, take 80broncoman's input as a fair warning, the chance for things to fail will increase. All in how willing you are to gamble.

Ford only changed the piston quality in that last of the harder worked and heavier and more emissionized, usually sequential injected F's and E's. The last 95 to 96 model year pistons were the fix to the reliability problems of a stock 1965 to 1994 Big Six under extreme load. Its just the pistons that were suspect, and a lottery, and only when subjected to more load than 150 hp and 4500 rpm. When cammed, fueled and boosted, the stock pistons are outside there factor of safety.


Rebuilt with proper better than 65 to 94 spec pistons, and it will outlast some big boost.


A stock unboosted 4.9 that doesn't exceed the recommended rev limit would last indefinitely or at least a very long time, but when its boosted, it needs the better pistons. The stock pistons for most big six years were the Achilles Heal. Piston cracking is a problem in all the 4" bore engines, with the early Windsor 351's and 302's commonly suffering the same problems.

if you blow it up, your pistons weren't strong enough.

if they don't fail, they are strong enough.

simple as that.


in college some friends of mine campaigned a very competitive (120 mph, 12 second) honda civic with a D16 SOHC turbocharged with junkyard parts.

when they blew up one engine, they would go to the local junkyard, buy another D16, install it in less than 1 case of beer, and hit the drags the following weekend.

is a stock 1995 civic motor strong enough to handle 20 psi + of boost? sure... for a while. 2-3 engines at $100 a piece per summer was cheap fun... way cheaper than dumping $4k into a 'bulletproof' motor that you could still run lean by accident and melt anyhow.

EDIT: plus, it was way more fun beating high dollar import cars covered with trick race parts, in a rusted out, gutted, puke green civic del sol!


thats the kind of logic that always cracks me up on internet forum discussions. everything in the car from the tires to the radiator is designed for a certain set of conditions... if you push it, you're going to shorten the life span, but its not like a set of 100 mph speed rated tires are going to burst into flames at 102 mph... and your stock pistons aren't going to shatter at 6 lbs of indicated boost pressure.

i'm also curious about this '96 piston change thing, i just went through sourcing rebuild parts for my '91 4.9L and the only distinction in pistons that i can find is that in 90-91-ish they switched to a metric style 2.0 mm piston ring, but a lot of resources list both the metric and the std. size piston rings.

other than that i cant find any info that points to a different part number for '96... although northern auto parts lists a significantly more expensive rebuild kit for 95-96, they list the same piston as coming in that kit.

not that i'm arguing, i'm just curious how one could go about finding these '96 specific pistons and what the distinguishing characteristics are. Is there anything externally that identifies them or is it metallurgical?

Mine only say '4.9L' on them, and one of those casting grid code things. I'm very curious what the different pistons were throughout those years and how to tell them apart.

I have been told that the '91 shouldn't be the metric ring... i guess I'd love to hear that the metric ring/better piston thing happened at the same time... not sure how i'd go about finding that info, dealer parts catalog?

motzingg":2mpg1te8 said:

.........
thats the kind of logic that always cracks me up on internet forum discussions. everything in the car from the tires to the radiator is designed for a certain set of conditions... if you push it, you're going to shorten the life span, but its not like a set of 100 mph speed rated tires are going to burst into flames at 102 mph... and your stock pistons aren't going to shatter at 6 lbs of indicated boost pressure.

Click to expand...

I'm saying he is likely to crack or break the piston skirts on his older 300 engine. Even if it did Its going to make a little noise not lock up.

I KNOW what it takes to COMPLETELY shatter a piston (BTDT in my youth). And I didn't even use a forced induction.

They get really LOUD once the cast piston goes to the pan and that wrist pin in the rod is banging around in the bore.
But that is how you learn.

yeah, i guess the point i'm making is that you have to judge it based on your personal tolerance for failure.

most of my vehicles are marginally reliable, its in my redneck blood, shattering a piston skirt or blowing a head gasket isn't enough to deter me from trying something fun like throwing a blower on a poorly prepared engine. worst case scenario it was a 200 dollar lesson, and i go buy a new junkyard motor.

i'd be a lot more pissed if i dumped a couple grand into a badass fully prepped engine and melted a $200 custom forged piston, smeared a couple hundred worth of crank grinding or threw a rod through a freshly blueprinted and machined block.

there is a reason only a couple people on this forum are posting 5 figure mileage reports on their backyard forced induction builds.

80ford100":27r27qk1 said:

I am thinking about supercharging my daily driver 300. The current setup is as goes, 300 inline 6 stock compression, pistons, crank, comp 268 cam, ported and polished head with screw in rocker studs, stock rockers, comp cams hydraulic lifters, stock push-rods, offy dual port intake, heddman headers, summit 650 cfm carb, stock duraspark 2 ignition, and stock oil pump. I'm new to the supercharging thing and need to know what I will need, what supercharger, how to plumb it, if it will run with my current setup, what will work with 87 octane gas, and basically anything else that I can't thing of that I might need.\
I've had the taste of power and I want more, so I thought, put a blower whine under the hood!! :mrgreen:
Thanks, John

Click to expand...

The Eaton M112 supercharger from a Ford Lightning is a good match and can be found fairly cheap on Ebay.
The Eaton M112 is a roots type supercharger and is good for 10 lbs of boost.
you can make an adapter to mount the supercharger on your present manifold.
It will take some work to get the drive belt aligned between the crankshaft pulley and the supercharger pulley and to make a support for the idler/tensioner pulley and drive snout of the supercharger.

The 6th generation TVS Eaton superchargers are a lot more efficient and will run a lot more boost but are a lot more expensive.

There are the twin screw superchargers, Whipple, Kennebell, Lysholm that are very efficient and very expensive.

All the above superchargers are positive displacement superchargers and will produce boost from low rpm on up.

Then there are the centrifugal superchargers, Vortech, Procharger, Paxton.
These units build boost proportional to the increase in rpm.
You decide at what RPM you want max boost to occur and the supercharger's drive ratio is selected to meet that target.
You can think of it as a belt driven turbocharger.
It is also easy to add an intercooler to this type of system.

As been discussed a stronger than stock piston is highly recommended unless you like to take chances.
A 2618 aluminum alloy custom piston is recommended for this type of application.
Piston prices went up in 2014 and a 2618 alloy piston may be as high as $125 a piece for this application. It was around $100 a piece.
I just paid $125 each for a set of Diamond pistons for a V8 turbo application.
You are looking at an 8:1 compression ratio.

The 1965 - 1968 (no oil hole) connecting rods are a stronger option.
The beams should be polished and shot peened then the rod resized using ARP bolts.
The longer 240 rod from that year range allows a shorter and lighter piston.

As also previously stated, detonation under boost will damage the engine so a big "NO" on the 87 octane gas.
Use the highest octane pump gas available.