flat tappet to roller with other issues

[acidh3r3t1c]

I have a 5.0L from a 90 merc grand marquis im putting in my ford ranger and am using a painless wiring harness. They say to use the mustang ecu from for example 91 ho mustang and i have the one for a manual and what im wondering is how this will affect my firing order since the merc is the non ho firing order and the ecu is for the ho motor. I have it all in the truck right now but can easily pull it i have access to roller cams and heads from a 99 explorer will replacing the mercs with these and hooking up the ho firing order fix these issues or what might be some of my options. Im not in need of the ho power it would be nice but not necessary this is just going to be a daily driver/off roader. Another option i was thinking is an ecu from like a 91 f150 with a manual trany because this has the non HO firing order.

 

[Teddyzee]

The Mustang based ECU's are sequential fuel injection, each injector fires according to the spark order.
Non-HO 302/5.0 use batch fire, where all injectors (or all in one side) fire at once.

You'll need to put an HO or 351 style cam in there for it to work properly. If you have access to an Explorer motor, I would use the whole longblock.

 

[Psychopete]

Non-HO 302/5.0 use batch fire, where all injectors (or all in one side) fire at once.

I am not sure if that is just a truck thing or what, I am not sure what the story is behind it, but I am pretty sure my '87 non-HO Marquis engine was SEFI, grey top injectors and all.



Be sure to do your research on those GT40-P heads if you are going with headers! You'll need the orange top 19lbs if going with a newer style Mustang computer if your current engine has the 14lbs grey tops. Not sure if the cam swap is going to cause piston to valve interference(?).

 

[acidh3r3t1c]

I'm trying to avoid changing the block out if at all possible. I was just wondering with an HO upper and lower intake and say explorer camps and heads on the merc block will this work. I just dont know if the roller cams will go into the non ho block. And on the sfi vs batch if the truck is batch would it work with an ho intake and injectors with all of the ho sensors and what not?

 

[fordmike1]

The non HO engine will run just fine on the mustang computer even though it is sequential fire. We have swaped in non-HO engines into Mustangs using the mustang computer and wiring and the engines run just fine. Even the sequential fire goes to bach fire after 2500 rpm any ways. I have a Mustang sitting here at my place right now that we put in a engine from a Crown Vic wagon and it runs great and makes suprising power for a non-HO engine. It will work just fine.

 

[Teddyzee]

The sensors and all hard parts can be swapped, but it will not run correctly mixing sequential EFI with a non-ho cam.

This is based on info from www.fordfuelinjection.com and www.sbftech.com. I cannot quote a specific reference right now due to time.

I have no doubt it will run, but not ideally.

 

[acidh3r3t1c]

ford mike what about the firing order differences between the two engines?and my question about the truck ecu is will it work with the different intake because the 5.0 intake from the trucks is too tall and interferes with with the heater box? Also is it possible to switch the roller cams and explorer heads into a flat tappet block? also i just was informed that the 89 mercury might not be a flat tappet is there identifying marks on the block to tell me if it is a roller or flat cam?

 

[fordmike1]

ford mike what about the firing order differences between the two engines?and my question about the truck ecu is will it work with the different intake because the 5.0 intake from the trucks is too tall and interferes with with the heater box? Also is it possible to switch the roller cams and explorer heads into a flat tappet block? also i just was informed that the 89 mercury might not be a flat tappet is there identifying marks on the block to tell me if it is a roller or flat cam?

Yes the firing order is diffrent but it will run just fine and dont try and change the firing order of the injectors as that can cause you problems. The truck ECM should work just fine with a HO or Explorer intake and I am just doing this setup myself. I am putting a Explorer 5.0 into a 87 F150 and using all the 87 F150 wiring and ECM on it to. All the 5.0 blocks were roller after 88 if I remember right. Baddad can chime in and give you the correct year if he will.

 

[acidh3r3t1c]

so keep the non ho firing order?

 

[Iron Ranger]

If you keep the non-ho firing order, you're gonna be beating yourself up for not going HO simply because the non-HO's are pretty mild in power.

As long as your block has this:

There are 2 places where the spider hold down screws into the block. The roller blocks have 2 built up cast chunks that's drilled and tapped already. Your's may or may not be tapped, but the chunks should be there. Only way to tell is to remove the intake.

I've gone from flat tappet to roller, non-ho to ho firing order and computer from a 93 mustang, and the added power was breathtaking...........

 

[acidh3r3t1c]

so if i get the intake off and discover it is a flat tappet block and not drilled and tapped i will have to do that to convert to the roller and then install the cams along with the roller lifters? and if i want can put the explorer heads on? also if it is a roller i can just install the roller cams and explorer heads and all is good to go?

 

[Iron Ranger]

As long as your block has those 2 chunks, tapped or not, then you can drill and tap them yourself(just be carefull). Some early blocks(I believe pre 70's) don't have those chunks at all.

If it is a roller block, the 2 places will already be drilled and tapped. A roller cam needs roller lifters, and to run roller lifters you need the dogbones and spider hold down to hold the dogbones in place(as seen in the pic).

As for the explorer heads, as long as you don't use an extreme cam with so much lift that it would hit the pistons, I don't see why not. I used Edelbrock aluminum heads on mine, so I'm not 100% positive.

 

[Psychopete]

'90 Marquis is a roller engine.

The non-HO computers that are SEFI are designed to be used with the non-HO engines with the 5.0 firing order and vise versa for the 5.0L HOs w/ the 351W firing order. The batch fire would probably work, but IMO I would rather go with what was recommended with the harness, not unless you want to hack that expensive thing to make it batch fire (or just get the right harness). You can experiment, but good luck diagnosing if it doesn't work out.

Also - there is only one cam...

Heads are going to be off so piston to valve clearance can be checked...

As stated before, sounds like what you want is a different 5.0L. Rebuilding what you have to make it an HO is going to cost more than just selling what you have and getting a used HO. '91 Mustang will even have forged pistons for instance..

 

[acidh3r3t1c]

just pulled the intake off it and it has a roller cam in it already so all i have to do is install the explorer cam and heads if i want but that shouldn't be necessary heads could be done at a later date im not going for something extreme at this point just trying to get this project running and driving for now

 

[fordmike1]

so keep the non ho firing order?

Yes.

And like you said you dont need the power so who cares what cam and how much power it makes its a DD.
Now I myself would do the HO cam......No wait I would use a E or F cam and step up the heads and make more power just becuse I am a power junkie.