5.0 help

[slystang]

I'm building up an engine out of an 87 mark VII to drop into my mustang. I was wondering if I had an H.O. motor. There is no H.O. badging on the upper intake manifold. I need to know what computer to order, the different motors have different firing orders.

[mdcluth]

Easiest way to find out what computer to buy would be to use the engine code from your build tag. You can find the info on the tag by the driver's door latch post in the door well. 302 H.O. has an "M" code.

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Mark D. Cluth

[slystang]

Unfortunately, I dont have the whole car. I just have the engine. Are there any distinctions on the block? The engine didn't have the valve covers on it when I bought it, so the tag that would normally be there isn't.

[Lscman]

It sounds like your Mustang was not a V8 from the questions you're asking. Is this correct?? If so, you have your work cut out for you. I have all necessary swap components in a big box for shipment! The '87 Mark VII motor was a bastard wannabe '87 HO motor. It was actually manufactured using a mix of '86 200 HP HO and '87 225 HP HO Mustang parts. First off, the '86 HO Mustang and '86 HO Mark VII engines are the same. The '87 Mustang HO motor had many new parts that the Mark VII line did not recieve until '88. Many, if not all '87 Mark VII's had the '86 style intake and smaller 58mm Throttle body. Some even had the flat top pistons and high swirl heads from the '86 motor. They can be identified by looking at the spark plugs. They are shaped uniquely for the early motor. DO NOT DISCARD THEM, since this is the simplest identifier. The Mustang and Mark VII '86 and '87 motors are so similar that you can use any '87 Mustang computer for the conversion. All Mark VII's and all '87 HO Mustangs used Speed Density computer and were rated at 225 HP. The 49 state '88 Mustang HO computer will work too.

[slystang]

right now my car has a 2.3L 4-cyl. I decided I'd swap in a 5.0L. I guess I'm gonna switch my engine over to carbureted, so whether or not it's H.O. really doesn't matter now.

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[Lscman]

The conversion project from 2.3L to 5.0L will cost more than buying a used 5.0L Mustang and it is a huge, time-consuming project. I would strongly advise against it. You can not buy things like V-8 radiator, transmission, clutch, bellhousing, non-EFI distributor, clutch, motor mounts, driveshaft, intake, exhaust and carb etc for a 5.0L's book value of $2K-3K. Plus, it will not pass emissions. The engine block is only 1 part that's worth less than a $200 '85-style carb-compatible factory distributor.

[Avu3]

I'm not a mustang expert, but I also remember a discussion with some other folks who said there is chassis stiffening that has to be done to a 4 cyl too. I think some of the suspension parts may need changing. Also, the rear end may be a 7.5", not the more durable 8.8 that you'd want. I had an 85 Tbird that had a lot of the lesser durable parts that would have needed upgrading for any kind of performance mods.

[Lscman]

Depending upon the year, the spindles, struts, calipers, rotors and hoses are different on a V8. Then, you may need new wheels to fit over the larger brakes. There's another grand or so. The front K-Member/chassis is the same on all motors, although the springs are different. The car will ride like a Pinto carrying a ton of gravel on the hood until the 4 cyl 350 lb/in springs are upgraded to about twice that rate. Yes, the 4 cylinder 7.5 axle is marginal but it'll work as it did in the '82-'85 HO cars. The electrical issues are not simple either. a conversion to V8 is only practical for off-road racing use or when you have a V8 salvage vehicle sitting right next to your 4 cylinder that you bought for next to nothing. A careful process of removing and reinstalling parts one-at-a-time (in an assembly line fashion) from the radiator to the rear axle can lead to success if you have many free manhrs. Even stuff under the dash is different.

[This message has been edited by Lscman (edited October 27, 2000).]