Should I put a used Eaton on my NA 3.8?

wmullen9638

Registered User
Should I put a used Eaton on my NA 3.8?
My trans mechanic has the leftover parts to a supercoupe that was totaled recently. Should I even consider adapting my 96 3.8 to use this equipment or is it more trouble than its worth. Could I have it rebuilt and put a higher psi pulley on it?
Or should I just wait to get an aftermarket kit?
I already planned to go w/ the 4.2 crank and several other heavy mods(possibly split port conversion). Is this a steer in the wrong direction or is this the path to low cost H.P.?
 
i believe everything will fit but i think you'll blow up the engine if you did that. the sc engine/block is built stonger to hold up to the supercharger. maybe if you mod the engine with more durable internal's it would work but im pretty sure the n/a block wont take it. i also know nothing about the split port maybe thats possible but i think the intake design is different, im sure someone else can add to this.. maybe start with an sc block and build the engine the way you want it and use the sc blower set-up on top of that...
 
I'm fairly sure if done correctly the N/A will survive a little SC love. :)

2003 Mustang Mach1
1995 Thunderbird LX 4.6
1995 Mustang 3.8;
M90 Supercharger/10%OD pulley, 80mm Maf, 70mm TB, 42lb injectors, SC Heads, 255lph Walbro, Xcal2, AODE w/Jmod, 8.8 3.73 Tracloc, Tokico Stuts/Shocks, C springs.
 
OK, I agree to both sides of this.
The original SC engines had forged internals. But, i do believe the cast parts could handle some SC.
However the person selling no longer has the original block. Probably let it go not knowing what they had.
I'm questioning the overall conversion cost, wondering if the small parts are going to add up to a bigger price tag. Would a procharger kit or vortech be a better buy than rebuilding and fitting this Eaton and converting the upper motor?
 
forged int

i guess my 94 missed out on that too? anyways forged is not the way to go, the clatering and the mess of getting the engine balance, right i will go with oem. anyways you are forgetting about all the vaccum lines, nothing but a mess if they are not there?
 
There is way to much to change. The ignition system alone will drive you nuts. It can be done done but with lower psi levels. A tune after a must. I have a na engine here that had a sc on it for 3 days and has a hole in one of the pistions the size of quarter. Thats how I got the motor. If I were you I would look for a 4.6 to come along. Yank it, put in a dohc from a mark 8 add vortec,injectors,rear gears. Or get a SC. Now your cookin;)
 
One of the original problems Ford had developing the SC's engine was that it broke the cranks due to the high torque from the roots blower so more than likely you will eventually break the crank. They would only last about 8-9000 miles. Instead, use one of the centrifugal blowers and you won't have that problem. Supersix Motorsports uses these quite successfully.
 
Yeah good thoughts, Thanks again
I'm thinking their is just not enough good things to say about this.
Probably going to go w/ rebuilding a 3.8 w/ the split port and just go w/ the procharger centrifugal w/ intercooler kit.
So do you guys think the forged internals aren't necessary for supercharged builds? Maybe if I keep it just under 400hp.
Do you think the cast internals could take that kind of torque?
 
The SC 3.8's did in fact come with a forged crankshaft. I dont know if that holds true to all years though. My 89 & 91 both had forged cranks.
 
How are you able to tell a forged crank from one that isn't? I've never heard of an SC having a forged crankshaft. :confused:

Thomas
 
just my 2 cents but i wouldnt do it personally. as a few of you guys said the SC block is stronger. youll prolly end up spending more on repairs after installing the supercharger then you really want to. it could be done but with a low boost setting. so thats what i think. if you can make it work more power to ya.....:) and my 91 has a forged crank as well
 
I gues we'll just have to build a stronger lower end for the SC then. Sounds good just more money.
And about the forged cranks, I was never under the impression that it was even in question. I guess its possible they didn't all come w/ forged cranks. But I assumed they did due to the problems w/ twisting the cast ones.
I'm not sure how to answer that question for you, you'll have to seek out someone w/ more experience inside the SC motors to answer that.
 
Yes, SCs came with forged cranks. Everyone talks about the early 89s having week duracast cranks, after 17years im sure there are none left. I was told there was a good chance they were all replaced well withen the warrenty period. Did this board get really stupid or what? This is common knowledge that has been preached on this board for the 7 years i have been on it.
As for you wanting to put a SC system on you'r 3.8 NA i would lean more twards on of the centrifical kits on the market for the 3.8 mustang. You cant use the SC roots blower if you switch to a split port head, no one makes a lower intake yet. I wouldn't be worried about installing a roots blower on a sound 3.8 if boost was kept around 10psi with a decent IC, exhaust, and a good tune.
 
Yep, BKB hit it on the head. There were some made with cast cranks in 89, but my 35th definately has a forged crank (it weighs a ton compared to a cast 302 one).

You could get away with an eaton setup, if you were to underdrive it to run the boost down. Under the full 10-12lbs of boost you'd get just slapping it on, you'd more than likely blow a head gasket anyway, due to the higher compression of the N/A motor. I've heard of people running 6-8 on an N/A motor though.
 
I think if properly tuned and you had the right injectors and fuel pump, you could probably keep it around 8 - 9 psi intercooled on a stock 3.8L NA. But it'd be safer to build a forged lower end.

Personally I'd rebuild the 3.8L w/ an SC crank, forged rods and pistons, a cam, ported split port heads w/ bigger valves, ported upper and lower intake, bigger throttle body, a turbo, and the proper fuel system and you could easily make 400 hp.
 
Finally some good knowledgable advice!
I'm still new to a lot of this, so all responses are greatly appreciated, but I was a bit shocked to not get more knowledgable responses. Great guys! Thanks Again!
I think I will plan to go ahead w/ the centrifugal setup though. The seller wants too much for the eaton and I wouldn't feel comfortable putting it on w/o having it rebuilt, so up goes the cost again. Might as well just go w/ a new one!
But, how much HP do you think the cast cranks could take? is it even considerable, or is forged the only way to go w/ this?
 
I think you are on the wrong board, try V6power.net. There are a few stangs running around 400 rwhp on stock bottom ends with no problems. Its all in the TUNE. The 4.2 truck cast cranks are very strong and a cheap upgrade, if your motor is high in mileage just look for a low mileage 4.2 from a wrecking yard. That with a simple centrifical blower would make a nice cheap set up for you'r bird.
 
I'm running 12 pounds of boost with a M90 on a Mustang NA stock bottom end. I do have a custom tune also.


2003 Mustang Mach1
1995 Thunderbird LX 4.6
1995 Mustang 3.8;
M90 Supercharger/10%OD pulley, 80mm Maf, 70mm TB, 42lb injectors, SC Heads, 255lph Walbro, Xcal2, AODE w/Jmod, 8.8 3.73 Tracloc, Tokico Stuts/Shocks, C springs.
 
just my 2 cents but i wouldnt do it personally. as a few of you guys said the SC block is stronger. youll prolly end up spending more on repairs after installing the supercharger then you really want to. it could be done but with a low boost setting. so thats what i think. if you can make it work more power to ya.....:) and my 91 has a forged crank as well


i know my 91 has a forged crank.....

but did the sc come with forged pistons and rods?
 
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