StangFreak

Hey guys, got a question and I hope some of you can answer from experience. I have a 90 GT convertible which I would like to start doing some motor mods to. Up to now all of my mods have been either the suspension, trans or appearance mods (see my sig). I have 105,000 miles on the car and am a little leary about modding a motor with that many miles. I've had my local dealer do a compression/leak down test and they told me that there was no loss of compression in any of the cylinders. Even so I'm considering a rebuild or just replacing the motor with a Ford crate motor.

The main set of mods I'm considering are a set of GT40x heads, E303 cam, and a 93 Cobra intake. So my question is am I tempting fate by modding my existing high milage motor or would it be smarter to just spend the dough for a rebuild or crate motor???

luvthe440Aroush

how much money are you looking to spend...i'm a fan of the crate motor, if you have the cash by the ford racing 340HP long block with the B303 in it. if you cant have a B cam in your car get the 320HP engine with the E303 cam...i've seen them on sites for about 3k then you re-use or buy new the rest of the parts for the long block (buy the intake new, alternator new, ect.)

mr-mstng

I sold my 87 GT back in 94 and the guy I sold it to did a few mods and ran a 13.6 with 161K on the clock.

The 5.0 bottom ends are pretty solid, however, since you are going through the work of getting new heads/cam, an overhaul of the bottom end would not be a bad idea.

StangFreak

Thanks for the advice guys. I think I'm going to spring for a new bottom end and not tempt fate.

joker

105k miles is NOTHING on a 5.0. That motor is most likely just getting broke in good if it has been taken care of. Why replace something that isnt broken? Heads / cam / intake isnt going to cause any extra stress on the motor. You are mearly wasting your money by rebuilding the bottom end now. Wait till it blows then replace it. Keep the oil and filter changed in that motor, and I will bet you it will hold together atleast another 50 to 100k miles.

The only way I would recomend changing the bottom end now is if you want to put in forged rods and a forged crank, you already have forged pistons. There is no real reason to go to forged sutff now either unless you are planning on putting down ALOT of power.

MustangFanatic

I would certainly echo Joker's comments, unless you plan on boosting or spraying the engine, I wouldn't waste the money on a rebuild at this stage, unless you are REALLY going to be beating on the car. I've modded cars with over 100K before with no issues, just limiting the mods to mostly bolt-on items like heads, intake, exhaust and camshaft.

I8URVTEC

I would also have to say why not just mod it with the 105k miles on it. Worst case senario the bottom end goes...then just keep the mods you have...i.e. cam, heads etc and put them on a new block with new internals.

joker

Honestly, with only 105k on the motor, and it having forged pistons, I wouldnt even think twice about throwing about a 150 shot of juice on it either. As long as it is tuned right, you most likely wouldnt have any problems at all. THe motors are by far the strongest link in these cars. If you were gonna drag race it a bunch, I would worry about other things ( transmission, clutch, differential, axles, control arms, or torque boxes) going well before the motor ever does.

MustangFanatic

Definitely the 5.0 engine is the most durable part of the Fox beast. I've torn up transmissions and broken other various parts all while the engine just kept humming. I had a '90 5.0 Sedan with over 200K on the clock and just a few mild mods (exhaust, intake and heads) and it never used a drop of oil and had great ring seal. Save the dough on the bottom end and strengthen other areas of the car like the chassis.

StangFreak

The cars set up for more power with the Lentech trans and bracing I have in it so that I'm not worried about. The car is never drag raced and is only driven as a toy. I exercise it but don't thrash the crap out of it. By adding the heads, cam and intake I figured it wouldn't be putting any stress on the motor. I may just go ahead and do it. I'm not planning on doing any thing till spring so I have some time to think about it.

conv_stang

i would leave the bottom end alone. unless you are planning on like 400 HP. my sisters B/F has a 91 with like 220K and the engine still runs great. heads intake and cam shouldnt stress the bottom end enough to cause and major problems. and you had a compression check done and that checked out good.