View Full Version : Derek's Project GFP

09-22-2017, 08:34 PM
I would like to introduce my new project for my 1989 SC 5spd. Currently my car has a perfectly good 4.2 engine with an MPX that makes over 380whp on pump gas. It won its dyno class (M90) at the 2016 shootout. Its running somewhere in the high 12s at the track, trapping ~107mph, and it probably should go mid 12s with a better driver. Itís a great car, and I enjoy driving it to work when the weather is nice, which is most of the year down here in NC. I have learned a tremendous amount from these forums and wrenching on this car over the past 5 years. The car is a blast to drive and is pretty clean for its age. However, as is often the case, I have been bitten by the horsepower bugÖ again.

I have been considering my options for a while now. Should I put a bigger supercharger on it? Should I go turbo? Should I swap the engine? If so, which engine? Iíll share a little bit about my decision making process and let you guys understand where I am coming from, even if you donít agree with it.

Bigger supercharger: These are somewhat hard to come by and usually cost in the $2-4k ball park from what I have seen over the years. Then there is the cost of fuel system upgrades. The cars that I have seen with the ARs and the Whipples seem to make in the 450-500 whp range. While this is impressive, I donít think this option is for me.

Turbo: I thought a long time about just putting a turbo on the current engine. I really like the idea of a turbo, making more power per PSI. This is a bit more expensive option but Iím not really sure how expensive. I would guess in the $6k range. Add another $2k if you want to upgrade the fuel system and convert to corn. Binks has shown that you can make over 700whp with a turbo on E85. Concerns about converting to corn, and the overall stress put on the motor to run at this level are holding me back from this option.

Engine swap: A V8 should be easier to make the kind of power I want. So which engine to swap? The 5.0 is the obvious choice, mainly because it fits. David Dalke going 11.7 on a stock 5.0 with a turbo is pretty awesome. But we all know the stock 5.0 is a time bomb near 500 hp. Looking at Dart blocks to counter act this problem would add at least $2k to the price. And I wouldnít put stock stuff in a Dart block, Iíd have to build 347, and it would end up being $10k knowing me. And really when you get down to buying Dart Block, you can build a 427 almost as cheap as a 347. So facing that decision, I started considering the production 351w. From what I can tell, the stock 351 block can survive in the 600-800 range. My research tells me it will fit, it will be a pain, but it will fit. Iím liking this option.

So what are my goals? Iíd like to make a 700 whp street car. Iíd like to build a turbo car. I need a project and I really enjoy wrenching. I have recently added a tig welder to my shop, so I would love to use that to fabricate some of my own stuff. I have always wanted a 408 or a 427 sbf, why? I donít know, I just like big small blocks. Whats the budget? Im going to say ~$10k, but thatís over a couple years and this project is likely going to evolve. I kind of have the idea that I would spend about the same as I did when I built the 4.2, but end up with 700whp instead of 400whp. I am going to do a better job on this project to save money where I can, and spend it where required. RequiredÖ thatís kind of funny when you have a perfectly good engine in your car.

How to get there? Here is the loose initial plan. I am going to start with a stock 5.8 from E-150 van, a junkyard motor that made about 210hp and 325ftlbs when newÖ not that different than what a 1989 SC makes. The first phase is to get it in the car and running. Add to that finding an intake/hood combination that will work. The second phase is to add a turbo and get that working on the stock motor (with some big ring gaps). The idea is to run low boost, to figure tuning and what not with the turbo. If this phase works well, then the car might stay this way for a while. The third phase, the engine would receive heads and a cam. By this point I would anticipate that it should be making in ~500 whp range at this point on pump gas. Once all that is figured out, the plan is to ďbuildĒ the 351 into a 408 or 427. And somewhere along the way, I will be selling my current motor, MPX , and miscellaneous parts to help offset the cost.

So there you have it. Project GFPÖ Glutton for Punishment. Iíll give DD credit on the project name. However, that phrase has been muttered a number of times over the past few years by me and my cousin as weíve wrenched on the SC. This isnít going to be easy. Not exactly cheap. But it should be a lot of fun and provide a good long term project for me and the SC.

And here we go....


09-22-2017, 10:29 PM
Sounds fun! I wanna do a 351 in my 5.0 car someday.

09-25-2017, 01:10 PM
Cool, Derek :)

Sounds like we were on the same mental path this summer..lol.

Since I had a broken motor though, I chose to take the 3.8 further for now to get it back up and running. Glad I did, this time!

Be sure to post up your fabrication pictures...that's the real fun stuff, if you ask me. :)

09-25-2017, 09:01 PM
Awesome Derek! make I your own.

09-30-2017, 09:56 PM
For the last week or so, I have begun the process of tearing the motor down. I didnít want to do this, but when I did a leak down test, 4 of the 8 cylinders were at 50% or worse. #1 cylinder was the worst, holding 20-40% (which is 60-80% leak). I got the head off and tore it down. The exhaust valves are worn and pitted. The valve seats and guides look ok on the head, but the seats have some slight pitting. I ordered one new exhaust valve and some lapping compound to see if the head was salvageable. I lapped both the intake and exhaust valve on #1 and the valve and seats look pretty good now. I will order the rest of the exhaust valves and continue this process. I didnít want to spend any money on these heads (the stock heads are very poor performing heads), but for the sake of the project, spending $50 buck on exhaust valves is a lot better than having to spend $2k on heads at this point. I will have to take the heads to a machinist to remove the front most intake manifold bolt on each side that broke off when I removed the intake. I was able to remove the broke exhaust bolt and a broken water pump stud. After removing the rotating assembly, I also found that it also needs new rod and main bearings. The crank could also use a quick polish, but it really looks pretty good all things considered. Time to order some parts and get the block all cleaned up.

10-04-2017, 07:20 PM
Good luck with your new project buddy!!!

Will miss hanging out with ya this years Shootout man!

10-04-2017, 09:33 PM
Thanks Tom I am going to miss you guys too. I hate to miss the shootout, but its probably for the best this time around. This year got messed up with the job situation. I hope a lot of guys set some new personal best at the track!

10-04-2017, 11:40 PM
Any pics of this work??? I'm interested in seeing the photos that go with the descriptions of wear, tear and damage.

10-05-2017, 09:41 PM
Any pics of this work??? I'm interested in seeing the photos that go with the descriptions of wear, tear and damage.

I have not taken a lot of pictures of the tear down, because it is pretty nasty work, but since you asked :)

This is what the exhaust valves looked like...


This is what the main bearings looked like...


This is what the rod bearings looked like...


The crank looks pretty good. It mic'd to 2.9995 on the mains journals and the rod journals were 2.3102/2.3105ish. So they were still in good shape. I am going to hit them with some 600/1200 grit just to remove the superficial stuff.


10-06-2017, 01:40 AM
Cool - thanks!

10-06-2017, 10:47 AM
If you have a few hundred dollars in your budget you may consider trying to find some GT40 or GT40P heads rather than reworking those heads. They came on the explorer 5.0 engines and can be had for very cheap. It would be a lot of power for little money. If you get the GT40Ps you may need some work on the headers, as the spark plug angle is different on them.

10-06-2017, 12:28 PM
If you have a few hundred dollars in your budget you may consider trying to find some GT40 or GT40P heads rather than reworking those heads.

I thought about that. However, these heads only needed $50 worth of valves and then lap them in. These heads will be replaced with aftermarket heads at some point. I did not think it made sense to buy gt40 heads only to replace them again at a later date.

Its hard to resist the urge to do upgrades along the way.

10-06-2017, 04:46 PM
Its hard to resist the urge to do upgrades along the way.

...head spins..."but it's already apart", "really don't want to do this again if I don't have too".....:rolleyes:

I have a '99 5.0 sitting in a Mountaineer at my parents' place that honestly just needs a tune up (at 220,000 miles, only ever replaced the radiator and water pump once). Chassis components started going bad though, and the body is rotting out so I parked it since I already had my truck at that point. Still on the fence of whether I want to do anything with it. Thought about it going in my '91 more than once, but we're doing baby steps first.

10-06-2017, 07:15 PM
Didn't some of those Mountaineers/Exploders have GT40 stuff in them too?

10-06-2017, 09:57 PM
Didn't some of those Mountaineers/Exploders have GT40 stuff in them too?

Yep, the heads were GT40 heads.