4.2 with supercoupe engine??

BIGDOGCQ2

Registered User
Alot of the mustang guys are running 4.2 F-150 engines. Extra displacement is always a plus. I am thinking of running a 4.2 with my turbo set up now but would like to use the supercoupe rods and pistons because they should be much more durable.
Anyone here have any knowledge of this?
Will the supercoupe rods and pistons work with the 4.2 crank?
Any idea what compression ratio I would be looking at? What is stock on a supercoupe motor?
The more information I can get the better, THANKS~!
 
BIGDOGCQ2 said:
Alot of the mustang guys are running 4.2 F-150 engines. Extra displacement is always a plus. I am thinking of running a 4.2 with my turbo set up now but would like to use the supercoupe rods and pistons because they should be much more durable.
Anyone here have any knowledge of this?
Will the supercoupe rods and pistons work with the 4.2 crank?
Any idea what compression ratio I would be looking at? What is stock on a supercoupe motor?
The more information I can get the better, THANKS~!

No you can't use the SC rods and pistons with a a longer stroke crank. They will be too long. Stock compression on an SC motor is 8.2:1 89-93 BTW, I would be more concerned about the 4.2 crank being cast instead of forged.

Morana has been selling a 4.2 stroker kit for the SC motor for several years. Contact him and he can tell or sell you everything you need. I know of at least one guy with an SC that used an entire 4.2 block and rotating assembly and bolted on his SC heads and intake onto it.

I would only do it (stroked crank) as a last resort to gain more power, and I wouldn't use a cast crank. BTW, The stock 3.8 bottom end is probably strong enough to support 400 rwhp.

David
 
With a turbo you don't need more displacement, just crank up the boost. The hardest part is going to be tuning. Regardless of what you do, if you can't keep the right mixture in there nothing is going to last.
 
the Ford 4.2 crank is way better than any of Morana's. The Ford 4.2 crank is surprisingly strong for being cast, and I wouldnt mind putting it in a mildly modded sc, but Im not sure I would take it much further than that, but the only way to know is to do it and I doubt anyone here wants to run that risk. But you could have it hardened to withstand a bit more power. You will need to use 4.2 specific pistons and any kind of 96+ length v6 rod would work, but I would go aftermarket forged with both items.
-Thomas
 
oh you are correct, I remember reading that, it was the 4.4+ cranks that he sells that are weak. Sorry for the confusion.
-Thomas
 
eVen the PM rods in the 4.2L short block are suprisingly strong. I have a 4.2L truck bottom end that is being prepped for my car for '06.
 
I assume the crank is pretty strong. A guy ran an 11.3 1/4 with a stock 4.2 block. Had a turbo setup. He ran lean or something at the end of that run and bent a rod...... but hey thats not the crank.
 
Sorry about the wait(4.6L Supercoupe)

I just talked to the machine shop(droped off money).He said the the crank fit and the block is now gonna be bored as for as possible.He said not to get to happy ,but he's gonna try to get it to a 4" bore !(He is a Ford Guy)He's gonna double check it ,but it might work......I hope.Oh Yea , studs are gonna be used in every hole.And using chevy rods and pistions will save me alot of money.
 
I was told that .040 was as far as you could bore a S.C. motor. I like the idea of a 4.2 crank but being cast would worry me. The longer stroke and more cubes should make a lot of torque. Keep us posted on how it turns out.
 
are you kidding? He's going to bore the block .190" over? Max I'd ever go is .060" .190" is freakin crazy.
 
tim said:
I was told that .040 was as far as you could bore a S.C. motor. I like the idea of a 4.2 crank but being cast would worry me. The longer stroke and more cubes should make a lot of torque. Keep us posted on how it turns out.

What month was your car made? Your crank could be duracast and not forged. The 4.2 crank is pretty strong, I just wouldn't puta lot of power to it from a roots sc.
 
BIGDOGCQ2 said:
I assume the crank is pretty strong. A guy ran an 11.3 1/4 with a stock 4.2 block. Had a turbo setup. He ran lean or something at the end of that run and bent a rod...... but hey thats not the crank.


what car was this? I know Pete from Fordchip ran an 11.385 on his procharged 4.2 but I've never heard of this turbo 4.2 you speak of. I'd like to learn more about it though, if possible.
-Thomas
 
Thomas said:
are you kidding? He's going to bore the block .190" over? Max I'd ever go is .060" .190" is freakin crazy.

HEY HEY HEY,I don't think it'll fly either,But he and the guys in the shop started talking and showing the polished and blueprinted crank to everybody in the shop at the time and got exited.But I do think .060 over is realistic,But if he sleaves the block it might work,he's builds racing engines so who knows?
 
My crank is forged. The reason I know for sure is that is has been apart. Everything fully machined. Didnt have to get the crank cut just polished. Also had it aligne bored. Like I said the extra cubes sound good. Maybe if the blower was not over driven? make more power with the engine and cut back the boost? 4 inch bore? Like to talk to that machine shop. Bore the cylinders all the way out and sleve the block? Dont make any sense to me.
 
Just thought I would update this with a minor correction since there was some intrest in it.
matthew neuharth with his 4.2 setup ran 10.3 not 11.3 would'nt want to spread bad rumors about his car.
Look like our 3.8's have alot more in common with the GN's than previously thought.
http://v6power.net/portal/timeslips/index.php
Thats a link to the fastest mustangs we have so far, I will make the top ten list next year I hope. Just need to decide if I should go turbo or with a Magnaport III setup.
 
I dunno about that. Kevin's 11.30 @ 123mph is good for #4 on that list and I am quite sure that a Mustang can be made lighter than an SC. I think it would totally kickass to see an M90 powered Stang in the top 10 of that list. Plus the positive displacement supercharger is nuts on the street. You'd get a lot more respect doing it with an M90 than you will with a turbo.
 
To bad we cant get a strong 4.2 crank that will not cost $3000. It would seem that the extra cubes would really help.:D
 
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