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**BigMerc96** · 08-25-2019, 09:31 AM

I...don't think I've driven a box faster than the stock 85mph speedometer. Then again, most of the boxes I've driven were a bit unsound in the suspension/braking department, except my buddy's wagon, but with 3.55s and a sad worn out LoPo it really didn't much like going over 75. Your car sounded WAY better and seemed way more planted to the ground than any of the boxes I've driven.

Ya know, I must just be getting older or something. I know first hand where the speed limiter was in my 2.73 equipped '96 GMQ (109), the 3.08 equipped Town Car (107), but I have never even attempted to find it in my '98 HPP. However, the past 10 years have seen all of our freeways crumble to the point where the 70mph speed limit almost feels like too much. Not that I'd do any of that on a public roadway of course.

**87gtVIC** · 08-25-2019, 10:35 AM

Originally posted by gadget73 View Post

THe feel of the car is somewhat important lest you be the one screaming as it goes off the road in a random direction.

Truth. It felt good so I kept laying into it.

Originally posted by BigMerc96 View Post

I...don't think I've driven a box faster than the stock 85mph speedometer. Then again, most of the boxes I've driven were a bit unsound in the suspension/braking department, except my buddy's wagon, but with 3.55s and a sad worn out LoPo it really didn't much like going over 75. Your car sounded WAY better and seemed way more planted to the ground than any of the boxes I've driven.

Ya know, I must just be getting older or something. I know first hand where the speed limiter was in my 2.73 equipped '96 GMQ (109), the 3.08 equipped Town Car (107), but I have never even attempted to find it in my '98 HPP. However, the past 10 years have seen all of our freeways crumble to the point where the 70mph speed limit almost feels like too much. Not that I'd do any of that on a public roadway of course.

The car is far from stock. It took AGES for the old LOPO in this car to reach any triple digit speed. This motor does it with ease and I now have the suspension and braking to feel confident enough in doing so.

**gadget73** · 08-25-2019, 11:06 AM

thats the trick though, extra motor in a worn out shitbox that can't be controlled is no bueno. I did that for a while, and trust me when I tell you its sketchy. With the suspension in good order these feel solid well into triple digits but I don't think I've ever had mine that fast. best I know of is about 120, and that was when the heater core blew up. I haven't repeated that with an actually better performing engine.

**DerekTheGreat** · 08-27-2019, 06:27 AM

I once had my 1969 Fury III north of 130mph.. It got there fairly quickly with it's warmed over 318, I assume I was north of 130 because the speedo only read up to 120 and was buried below that. Wind noise kept getting louder and then the thing got real squirrely. I pulled right off the go pedal at that point. All stock suspension save shock absorbers.

Box stuff? I think I had my '85 at 100ish. Felt pretty good, just ran out of road.

**packman** · 08-27-2019, 03:33 PM

I had to change the suspension in the '86 CV because with just the worn out lopo, it was floating quite a bit; and that was at 70mph. Can't imagine anything over that speed with the stock suspension.

**sly** · 08-27-2019, 04:13 PM

If you get the back end up a little (even an inch) over the height of the front, it helps a lot. When you're catching air under the car, it helps it float. I was more concerned with drive line and wheel vibration at anything over 70-75mph in the Mad Marquis. It was stable to 95 though. I think that was as high as I ever got it going. The aero with a little rake is much more stable. Though right now, I need to check my front wheel bearings. Something wants to hum when I get over 80. Might just be the new tires with the thick tread.

**gadget73** · 08-27-2019, 04:22 PM

yeah, nose-up NG. It just lifts the front end and you lose steering.

Aeros make a lot less annoying noises at speed than boxes do. The complete lack of aerodynamics becomes audible. Towncars at least whistle loudly over about 100, pretty sure its the mirrors.

**DerekTheGreat** · 08-28-2019, 06:19 AM

Haha yeah, can confirm. It's like the old speed warnings from the late 60's and into the early 70's where there was a red line or something past a certain speed, only they traded that for something audible and irritating.

**BigMerc96** · 08-28-2019, 10:23 AM

Originally posted by DerekTheGreat View Post

Haha yeah, can confirm. It's like the old speed warnings from the late 60's and into the early 70's where there was a red line or something past a certain speed, only they traded that for something audible and irritating.

A lot of cars had the 55mph mark circled or otherwise highlighted well into the '80s. An artifact of the 55mph national speed limit.

**DerekTheGreat** · 08-28-2019, 10:58 AM

LoL. Tell me something I don't know. I do not own a single car post 1992.

**gadget73** · 08-28-2019, 04:33 PM

No circles on my digital speedo but it stops at 85. The Townie has a circled double nickle mark. I think all boxes did, at least all the 80s ones I've been in.

**DerekTheGreat** · 08-29-2019, 05:51 AM

That's how my Townie is. Firebird has the double nickle bolded and in red. Although none of our GM trucks have that. I can't remember if the original slice 'o' pie cluster from my '89 had something special for 55 or not. I think it was also to remind people that 55 was approximately where best MPG was obtained.

**87gtVIC** · 08-31-2019, 04:14 PM

New Replacement Oil cooler Install

Got around to installing a new oil cooler today.

Some may remember back in May when my stock ford oil cooler started weeping from one of the fittings up at the cooler which turned out to be a cracked threaded boss. http://www.grandmarq.net/vb/showthre...l=1#post829479

I wanted to find a used replacement....and started a looking to buy thread: http://www.grandmarq.net/vb/showthre...ine-Oil-Cooler

I then thought about the chances of those being damaged and just flat out old and potentially sludged up so I then set out looking for a direct replacement part.

I stumbled upon this: https://derale.com/product-footer/fl...n/15405-detail

I checked out the dimensions:

and Compared it to the stock ford unit and the numbers came up very close.

So I purchased the kit and then installed it onto the car with all of the factory ford lines and adapters. They all just fit right into the new cooler!

The new cooler just needed one hole enlarged and the factory ford lower bracket needed its slot for the J nut/j clip slotted out some. Otherwise a direct fit.

Upper mount:

and lower mount:

Super happy with the outcome and No need to worry about installing a used oil cooler.

If any body happens to want the remnants of the derale kit (I just used the oil cooler) let me know and we can work something out. I have no need for it.

Attached Files

**87gtVIC** · 10-06-2019, 10:08 AM

Took the car out for the first time in three weeks. Started right up without issue. Romped on her for a few hours and took these pics before putting her away:

5sp swap finally coming this winter...Car has been very good to me the past two years. Gonna go ahead and do the swap.

Attached Files