1990 Grand Marquis 5.0 EFI motor - need input.

[88 Sleeper Coupe]

Okay guys.. here goes.. I need to know the difference between an HO and non-HO 5.0 EFI motor. Guy has a 1990 grand marquis with like 86k miles on it and says I can drive the car to see that its a good running motor. I know the intakes face the other side..(why?) but other than that looks exactly the same. Says if I come pull it out I can have the entire motor manifold to oil pan for $250.

So whats the difference? Would it have a forged bottom end being a 1990 motor? Where the heads just different? Should still be a roller cam motor? I don't see a 1990 302 being a non-roller.

Can someone please tell me if buying this motor as a backup block/motor thats in running condition for $250 being a good deal? I want to use it for mock-up reasons for a project with my motor but also as a back-up block/motor incase mine fudges up.

Thanks for any insight guys. I know its not an HO but is it a good deal?

[04 Mach1]

Yes its a roller block heads are the same Should have the dual sump pan. In my book its worth the 250.

[88 Sleeper Coupe]

someone on mustangforums.com said the same thing about a double sump pan. Whats good about that? All I heard from mustang forums is that its the same motor but with a different cam. Put a b303 cam or even stock HO cam and it'd be just as much power.

Question though.. being a 1990 motor why did they put the intake on teh other side? Just because they did for that model of the motor/car? Also.. besides cam is it gonna be a forged bottom end being a 1990 car?

I'm gonna try to talk the guy down to $200 since I have to pull it.

[Italian LX]

All I heard from mustang forums is that its the same motor but with a different cam. Put a b303 cam or even stock HO cam and it'd be just as much power.
That won't work. The firing order in a Non-HO 302 is different; the lobes would be hitting in the wrong order. You would have to get a custom ground cam.

[Italian LX]

Question though.. being a 1990 motor why did they put the intake on teh other side? Just because they did for that model of the motor/car?
The way the intake is facing is only due to the body it came out of. The Lighting 351W are facing the opposite way too.

[88 Sleeper Coupe]

he made it sound like I could throw in a different cam and just change the firing order to a HO. Sure that isn't possible?

[Italian LX]

he made it sound like I could throw in a different cam and just change the firing order to a HO. Sure that isn't possible?
Sure, you could do that... but he failed to remind you that you'd also have to change out the crank to one with the HO firing order.

[QWKSNKE]

Sure, you could do that... but he failed to remind you that you'd also have to change out the crank to one with the HO firing order.


:think:
The crank? Cam swap is all you have to do to convert a non h.o to a h.o. Crankshaft doesn't care they are all the same.

[88 Sleeper Coupe]

Lol so whats the answer? I got mixed oppinions. So just a HO or upgraded like b303 cam and changing the firing order of the distributor would convert it to HO?

[Italian LX]

:think:
The crank? Cam swap is all you have to do to convert a non h.o to a h.o. Crankshaft doesn't care they are all the same.
Yeah, you're right. I was thinking I had read somewhere that the cylinders actually hit in a different order on the crank, but I was apparently mistaken.

Yes, all you would need to do is swap cams and rewire the plugs.

[QWKSNKE]

Lol so whats the answer? I got mixed oppinions. So just a HO or upgraded like b303 cam and changing the firing order of the distributor would convert it to HO?

cam swap is all you have to do

[88 Sleeper Coupe]

sweet.. well i guess im gonna try to organize picking it up sometime then.. i'll go ahead and call the guy..

hey even though its not HO would it be forged bottom end since its a 1990 motor?

[joker]

sweet.. well i guess im gonna try to organize picking it up sometime then.. i'll go ahead and call the guy..

hey even though its not HO would it be forged bottom end since its a 1990 motor?

I am not sure if it would be the same internals as a 90 mustang 5.0. For example I dont think the lincolns mark vii's came with forged pistons.

I am not correcting but want to make sure you arent misinformed. The mustangs didn't come with a forged bottom end in the 5.0's, only forged pistons. I believe the rods and crank were still cast pieces. In fact the only mustangs that I know of (I could very well be mistaken though) that came with a complete forged bottom end were the 03-04 cobras.

[TheJeanyus]

In fact the only mustangs that I know of (I could very well be mistaken though) that came with a complete forged bottom end were the 03-04 cobras.
I believe that is correct. :yup:

[04 Mach1]

Yeah, you're right. I was thinking I had read somewhere that the cylinders actually hit in a different order on the crank, but I was apparently mistaken.

Yes, all you would need to do is swap cams and rewire the plugs.

:bad:

[CrazyInBlack]

I am not sure if it would be the same internals as a 90 mustang 5.0. For example I dont think the lincolns mark vii's came with forged pistons.

I don't even know that

[88 Sleeper Coupe]

well thats what I meant forged pistons... think they're forged?

So only thing different in this motor is gonna be the cam? even if its hyper bottom end it'll have just as much or more power output if I just swap in a b cam? and based on qwksnake I won't have to change the firing order of the plugs?

[QWKSNKE]

b cam = ho firing order

[CrazyInBlack]

Mark lower end is the same, not sure about the Grand Marquis

[86GT]

You will also have to get a custom chip. The firing order is different, therefore the EEC will not work the way it is programmed.

You can either re wire the injector harness or get a chip. As for the crank it is the same on both HO and Non HO. All you need is the CAM and the chip.

[QWKSNKE]

I think he is going to use his mustang harness Clint

[86GT]

If he plans on going the chip route then all that is needed is to change the firing order in the tune.

If the chip is not going to be done then the same harnes can be used but the pins on the salt and pepper connectors will have to be rewired. I do NOT think that just slapping on a mustang harness will do it. I believe the inputs to the EEC are in the same place.

Edit:
I just looked up the EEC pins and both use the same pins for the injectors. All that is needed, is to match the firing order with the injector outputs of the processor. You can either change the pins at the EEC or at the salt and pepper connectors. I would do it at the salt and pepper connectors.

[QWKSNKE]

If he plans on going the chip route then all that is needed is to change the firing order in the tune.

If the chip is not going to be done then the same harnes can be used but the pins on the salt and pepper connectors will have to be rewired. I do NOT think that just slapping on a mustang harness will do it. I believe the inputs to the EEC are in the same place.

Edit:
I just looked up the EEC pins and both use the same pins for the injectors. All that is needed, is to match the firing order with the injector outputs of the processor. You can either change the pins at the EEC or at the salt and pepper connectors. I would do it at the salt and pepper connectors.

Unless I am missing something, he is buying an engine from a grand marquis to put in his mustang. So, other than a cam swap and turning the intake around (if he doesn't use his stock mustang intake) there is nothing else that has to be done. Unless he is getting the motor from a genrous salvage yard, he won't get the wiring harness anyhow

[86GT]

Yes you are right, If he puts a new HO cam in the Marquis motor and turns the upper intake around then the firing order will match.

I thought that he was using the Marquis EEC with a HO motor. I miss read that. oops.

I read into it, My father and I did just the opposite. We used a 289 with the injection system off an A9L motor in a 1966 coupe. We did not chip the EEC therefore we had to re pin the salt and pepper connectors. This was back in 1990 when we did this.

[CrazyInBlack]

damn this is a lot of trouble, i hope it is bad cheap