1991 GT Technical Information

[dreamer]

I have a 1991 Mustang GT Hatchback that I purchased about a year ago. Here is the thing. The guy I purchased the car from was not mechanically inclined at all and had the engine rebuilt by a speed shop in CA about 2 years ago. He knew that it cost a lot of money to rebuild it, but never really requested any of the specs as to what was done, all he knew for sure was it was tremendously suped up and had an E-cam installed. Over the last year I have been trying to research and understand what was done and have found some interesting info. However, I need some assistance in understanding if what I have found sounds right, and how I would check more. I have had difficulty in finding specific expertise, especially since the people have had no hand in tricking the car. I have contacted the speed shop, and they were of some help, but do not keep records for more then a year.
The car appears stock under the hood, unless you look closely- falls in line with tricking cars in CA- have to look stock to pass emissions legally
-Engine- 5.0 built by Manning Motorsports in CA- pretty positive taken to GT-40 specs using machining, grinding, and valve replacement
-Something was done to intake, MassFlow removed, no PCV valve, but passes emissions with flying colors!
-Rev limiter either removed, bypassed- speculate high performance chip
-shorty headers, flowmaster exhaust, 21/2 inch pipe to rear 4inch chrome - I did this
-R-4 Borg Warner 5 speed transmission? Is this the T-5- ford says it isn't stock?
-Poly bushings on front
The car definately doesn't sound stock and most agree it is a GT-40 motor. I want to supercharge it in the future, and am going to have to do some trans work soon. I am timid about doing too much though until I know more about what I have. Any ideas would be highly welcome.
Thanks-

[squeeeg]

GT-40 is the ford racing parts that were used on the 93 cobra and many other vehicles. The GT40 heads come in about 4 different varieties. There is also a GT40 intake.

You mentioned that the MassFlow was removed?? I assume that you mean Mass Air meter but i don't understand why anybody would remove that.

The stock 5 speed transmission is the borg and warner t-5. I have never heard of the r-4 but i would imagine that it is another type of transmission that they make.


My guess is that the bottom end is still stock. so keep that in mind when you supercharge it.

[dreamer]

Thanks for the input and your are right about the transmission- I actually just found out yesterday evening- it is a CR4- T5 for that year, probably came stock with the GT, as far as any gear work that might have been done, can't tell until I open the case I guess

I am not sure if the bottom end is stock but highly appreciate your advise and better to treat it as such when setting up for my supercharger. The cam isn't too rough and think it will handle a nice nominal boost, nothing too outragious but enough to push me over 500hp I think. After posting on here have realized that it might just be smart to pull the engine and blueprint a rebuild with the supercharger. Then there will not be any question as to what is inside.

You are also correct that I ment Air Meter, and I don't know why it was removed either except that it came stock supposedly after 88 and I don't have one... Makes it kind of weird though knowing things were changed and not sure why.

The car does scoot though- I don't play around too much (can't afford the tickets) but have taken several of what should have been faster cars- I attribute most of their losses on the fact most people don't know how to drive and then try to pass me! Doesn't work- even if they do have a turbo (subaru)

Thanks again-

[squeeeg]

Originally posted by dreamer
nothing too outragious but enough to push me over 500hp I think.

I wouldn't say that . The stock block will handle about 500hp but the days are limited when you are up that high. With those power levels you should be looking into a dart or frpp sportsman block.

[Bo408]

526-531 lift cam with a 290 duration... all roller, all forged internals... 373 gears steeda underdrive pullies, mac full length comp headers ram air intake 70mm throttle body 77mm maf all ported and polished intake manifold and heads it runs
What's that? :( :( :rolleyes: :rolleyes:
302 is in cubic inches, 5.0 is liters