My 351w Swapped 1995 Mustang GT

Paladin1001

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I am planning an engine build after my unfortunate cracked piston in the Mustang.

The current plan is:

-Dart SHP block, 4.125” bore, 9.5” deck height
-Scat Forged Crank, 4.00" Stroke 2.75" Main, internally balanced
-Scat 6.250 H-Beam Rods
-Diamond Forged 2618 Pistons, 1.25” Comp Height (0 deck), 6cc
-AFR 205 Renegade, 72cc chambers
-AFR 8019 Springs (for hydro roller, .650” max lift)
-Morel 5323 Hydro Roller Lifters
-MLS .044” Compressed, 4.125” bore (this lands me at 11:1 comp on the dot)
-Double Roller Timing Set
-FRPP Road Race Oil Pan (has windage tray, baffling, and crank scraper), pickup, gasket
-Melling 10833 High Volume Pump/ARP Driveshaft (planning for an oil cooler down the line)
-Will need to measure for pushrods later, of course
-ARP Head Studs
-Aluminum flywheel and better clutch, FRPP pilot bearing
-Victor Jr Intake
-Holley Sniper 800cfm EFI
-Bullet Custom Cam
-BBK 1-¾” LT Headers, will be 3” pipe back to the rear end, then turned down

Here's my full calculations:
View attachment 9155

This will add some weight over the nose, but we are going to try to counteract that by moving the engine back 1". The MM K Member moves the wheels forward 3/4" and the MM control arms add another 3/4". So in total, the engine will end up being 2.5" further rearward than stock. Obviously, that's not a ton of shift, but that also moves the trans/clutch assembly back too. Might as well do whatever we can and want while the engine is out and on hold.

In addition, I've done my best to do the math on the weight of the rotating assembly, etc. Here's what I have come up with:

View attachment 9154

Obviously, it's not possible to get an exact comparison of the weights, and I have ignored things that DO matter, like the addition of hydraulic roller lifters, shorter pushrods, etc etc, but it is nice to see that the approximations of the big things are fairly equal. I am reusing some things like roller rockers off the old engine. With an aluminum flywheel, this engine will be about 10 pounds lighter on rotating weight than the 357 it's replacing.

Speaking of, I found a good deal ($150!!) on CJ Pony Parts for an SFI Certified aluminum flywheel. This should be a helpful addition in autocross. Some people have had iffy experiences with aluminum flywheels, but with a stroked 427" engine, I'm not too worried about torque or power off the line.

I picked up the LMR ABS delete block. So that will be going on this weekend. That takes about 10 pounds off the nose of the car. I am also going to pick up a Wilwood proportioning valve. The front brakes lock up much faster than the rears, probably because of the 13" Brembo setup in front and the 10.5" stock GT in the rear. This problem was exacerbated by stiffening the car up all the way around.

The AC compressor removal will take out another 20 pounds.
The MM K Member will net me another 23 pounds.
The MAF Racing front bumper takes another 14 right off the nose.

So even though the Dart block is about 30 pounds heavier, I'll still be pulling some weight out of the front, not to mention moving the weight around.

Obviously, with the MM K Member and control arms, there will be some other changes. Bumpsteer kit, sway bar relocation, etc.

Once all the hard parts and engine are back in, the plan is to corner balance the car to get the best symmetrical handling we can.

When all of that is said and done, we should have a much better-balanced car than we had before. Not to mention a ton more power at RPMs more suited to autocross. With a 6800 rev limiter, there will still be plenty of range when we do hit the road courses.

I've reached out to both Kuntz and Craft Performance engines here in Arkansas to do the work. Kuntz has been incredibly responsive and answered the questions I had upfront. Even did some math on the engine out of the gate, quoted me two different cranks to match my budget up to my goals, etc. I asked Craft some questions by email and then had to call 3 times over the course of 2 weeks to talk to them. Not as good of a feeling as Kuntz gave me, and being comfortable with the engine builder is something I'm looking for.

The plan is to head down one day next week and get them some money to start building it.

From my own experience, I have an 86 I put a 351W in that Kuntz built back in 2001, its still running great, and is a beast. Jim Kuntz was a great guy, I did business with him a lot, I heard they got sold and Jim passed away but if the same folks work there its a top notch shop.
 
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Chris Stephens

Chris Stephens

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From my own experience, I have an 86 I put a 351W in that Kuntz built back in 2001, its still running great, and is a beast. Jim Kuntz was a great guy, I did business with him a lot, I heard they got sold and Jim passed away but if the same folks work there its a top notch shop.

Some guys may be the same, I am not sure. The guy I am dealing with is the VP, he came in when Gwatney Performance bought out Jim. But Jim stayed working for him after the buyout for several months, right up until he passed in 2019. With it being so recent, I am sure some of the old guys are still there. Gwatney has a good reputation around here, too, though mainly for late model LS/LT stuff. The guy seems knowledgeable. Prices are a little high, but nothing too crazy for solid work and a really responsive crew.

Thanks for sharing your experience! I was supposed to go there on Monday and meet everyone, tour the place, and get them some money to start, but we got a rare snow/ice storm, so I had to call and cancel.
 

Paladin1001

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Some guys may be the same, I am not sure. The guy I am dealing with is the VP, he came in when Gwatney Performance bought out Jim. But Jim stayed working for him after the buyout for several months, right up until he passed in 2019. With it being so recent, I am sure some of the old guys are still there. Gwatney has a good reputation around here, too, though mainly for late model LS/LT stuff. The guy seems knowledgeable. Prices are a little high, but nothing too crazy for solid work and a really responsive crew.

Thanks for sharing your experience! I was supposed to go there on Monday and meet everyone, tour the place, and get them some money to start, but we got a rare snow/ice storm, so I had to call and cancel.

I saw that storm, it was a bad one! If you go see if Larry is still there, I used to deal with him a lot and he was always knowledgeable and cool. If it's the same guys as when Jim owned it, it would be hard to go wrong dealing with them.
 
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Chris Stephens

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I saw that storm, it was a bad one! If you go see if Larry is still there, I used to deal with him a lot and he was always knowledgeable and cool. If it's the same guys as when Jim owned it, it would be hard to go wrong dealing with them.

I talked to my contact, and is Larry still there. He's the one working on my build, too. I'm pretty excited, I finally gave them the full go-ahead on the build today!

I've picked up some of the parts already. FRPP road race pan, a slew of ARP bolts and studs, McLeod aluminum flywheel, things like that.

I need to get it into gear and get some things done on the car. I got an ABS delete manifold, proportioning valve, stainless lines for the rear to install. Part of the plan with the new engine is to set it back 1", so I need to get the K Member in and installed and start test-fitting the new oil pan with the old block and headers.

I did get the MAF Racing lightweight front bumper ordered yesterday, along with the Stiffler's transmission mount and some other things.
 
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Chris Stephens

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Got some more parts ordered up today from my pal Nick at RoadRace1.com (who I highly recommend):
MM K Member MM MMKM-1
MM Steering Rack Bushings MM MMST-6
MM Bumpsteer Bolt Through MM MMTR-3
MM Control Arms MM MMFCA-11
MM Swaybar Relocation Bracket MM MMFSB-51
Universal Sway Bar Bushings MM 9-5168G
MM Pinion Snubber MMPS
MM Solid Motor Mounts MMSMM-1
MM Bumpsteer Gauge

Plus a Ram Powergrip Clutch from LMR.

Unfortunately, I just found out that the K Member will be back-ordered for 2-3 months. That really puts a damper on my plan to use the new K Member, new oil pan, and old block/heads/etc, to test fit setting the new engine back one inch. So that particular thing might get put on the back burner for now. I really want to do it, though, especially since I already have the Stiffler's cross member on the way. So it's just going to depend on how much time I have before the Hallett event that my family goes to in June. If I have all the other stuff sorted that I wanted to do, I may have time for the setback. But I won't miss the Hallett event just to do it.
 

Paladin1001

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I think you are smart to wait until it is how you want it, be patient, and do it one time, correctly. you will like Larry, he was great to deal with and I can say after all the years and lots of 7500 RPM shifts they built me a great motor.
 
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Chris Stephens

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As is fairly normal for anything I do to this car, the plan is changing a little bit. The engine builder called last week to tell me he was having trouble getting a set of AFR 205s. His offer instead was for a set of cheaper castings, but that he would do the CNC porting and flow bench work in-house and match them to my intake and exhaust. He thinks he can make a little more power with a larger cross section/more intake port volume without compromising the lower end power I'm after anyway, something he had mentioned to me before, and I turned down because I didn't want to pay for more port work and flow bench time on a new set of AFR CNC heads.

But with my timeline of having the car done by early June, I honestly thought it'd be cheaper and easier to get a set of CNC port AFR 205s than it would be to go the more custom route. But, I guess I'm going his preferred route now. It will be kind of nice to see the flow numbers on the exact heads going on the engine.

-Dart SHP block, 4.125” bore, 9.5” deck height
-Scat Forged Crank, 4.00" Stroke 2.75" Main, internally balanced
-Scat 6.250 H-Beam Rods
-Diamond Forged 2618 Pistons
-Kuntz CNC Ported/Matched Heads, 220cc intake ports, 2.08/1.60 SS valves
-Titanium Retainers
-Kuntz spec'd springs
-Johnson Short Travel Hydro Roller Lifters
-MLS Head Gaskets
-Double Roller Timing Set
-FRPP Road Race Oil Pan (has windage tray, baffling, and crank scraper), pickup, gasket
-Melling Pump/ARP Driveshaft
-.120" Wall Pushrods
-ARP Head Studs
-Aluminum flywheel and Ram Clutch, FRPP pilot bearing
-Victor Jr Intake
-Holley Sniper 800cfm EFI
-Kuntz Custom Cam
-Innovator West 205 Balancer
-BBK 1-¾” LT Headers, will be 3” pipe back to the rear end, then turned down
 

Daryl

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Very recently, my engine builder actually had to buy the AFR heads from Summit. Parts demand is insanely high right now.
Try Summit racing.com see if they have the 205’s
 
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Chris Stephens

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Very recently, my engine builder actually had to buy the AFR heads from Summit. Parts demand is insanely high right now.
Try Summit racing.com see if they have the 205’s

Summit doesn't have the 72cc/205cc AFRs. But it's alright to me, I'll probably be happier with the more-custom heads. Though it would be nice to say I have AFR heads, they weren't gonna be ported further and were gonna stay as they come from AFR. I'm excited at the prospect of some custom CNC and flow-bench work, especially with everything else I'll have in this engine.
 
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Chris Stephens

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Some photo updates from the engine builder. Things went a bit further than planned in the budget department since January...but I get the feeling I won't regret it...
170987303_1234966600282510_5219857906592007368_n.jpg 171048615_497815241592534_7931488063319864226_n.jpg 170703651_498214947883632_5894585348377074258_n.jpg 171007808_1563219643877540_9031273876243164682_n.jpg 171046933_1083391748738063_4055870339387246516_n.jpg 171031010_448020959614860_9029661938810395383_n.jpg 171288039_140530344672858_6824288864377725309_n.jpg 171031011_4105792969431187_6492938295137283462_n.jpg

OH, and this is only barely car-related, but I'm excited about it, so I will share...since I started dieting, I have lost 23 pounds! Probably half that was water weight from going to a lower sodium/healthier diet, but the racecar won't care whether it was fat or water weight anyway. I started monitoring my blood pressure, and I was averaging about 145/85 until I started meticulously counting calories, watching sodium intake, keeping cholesterol down, no sodas, no fast food, limited alcohol, etc. I've since brought my average BP down to about 130/80 in the past few weeks. Still not great, and I'm going back to the doctor at the end of the month for a physical and bloodwork, but it is a major decrease from where it was.

I'm only 24, but have been obese all my life. Junior year of college I spent a lot of time drinking beer and eating cheap pizza at the fraternity house. I am a 6'1", large frame guy anyway, so I carry my weight well and most people wouldn't peg me being as heavy as I am, but the fact is that it takes a toll and I NEED to lose it while I'm still young enough to do it (and save my health from the long term effects).

Here's to losing weight so I can go faster
1f37b.png
 

lwarrior1016

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Now that’s dedication! Good job on getting the weight under control and living a healthier lifestyle. A lot of folks don’t understand just how much of an impact it makes on your weight and health if you cut processed sugars (stock to things sweetened with stevia) and eat healthy carbs instead of processed white carbs.


The engine build is coming along nicely, I can’t wait to hear how it turns out.
 

Zutz23

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Congratulations on the weight loss, I’m on that adventure too. Has its moments but the rewards are amazing.

What are you doing for the build ? I’m looking to forge a 2v engine I have sitting. I’m by no means a mechanic and could use all the help I can get.


Sent from my iPhone using Tapatalk
 
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Chris Stephens

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Congratulations on the weight loss, I’m on that adventure too. Has its moments but the rewards are amazing.

What are you doing for the build ? I’m looking to forge a 2v engine I have sitting. I’m by no means a mechanic and could use all the help I can get.


Sent from my iPhone using Tapatalk

Thank you!

It's outlined up above a little more in-depth, but essentially doing a 351 Windsor-based Dart aftermarket block. Large bore (4.125"), 4" stroke (7.0l/427 cubic inch), Scat forged crank and rods, Diamond pistons, a set of custom CNC'd heads (220cc ports, 2.08/1.6 SS valves), 10.8:1 compression, port matched Victor Jr intake, Holley Sniper fuel injection and ignition system, short travel hydraulic roller, custom cam, track/autocross oriented oil pan, ARP studs, etc etc.

As for building 2 valve engines, I would not be much help there. I know enough about engines and engine building to be dangerous with 302/351s, but I am not as familiar with the Mod motors.
 
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Chris Stephens

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Couple more photos, engine builder says heads, intake, etc are done. All the parts are there, they are working on assembling the shortblock right now. There's one guy ahead of me, but they say dyno day should be no more than 3 weeks, no less than 2. Very exciting!

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Burninrock24

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Congrats on the personal health gains! This is a great build. I've always been intrigued by the pushrod motors. Being able to say you've got a 427 is awesome. If I could get my hands on an aluminum 351 block without donating a kidney it would be hard to not go this same route.
 
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Chris Stephens

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Man! What a great day!

My engine builder called me Monday afternoon and told me that the engine was pretty much finished. He had a guy whose engine was supposed to be on the dyno ahead of me, but they were still waiting on some parts. Asked me if I wanted to run it this week. Obviously, yes! But I was supposed to be going to Nebraska for work on Wednesday. Thankfully, I was able to delay my trip by a day and go dyno this bad boy. And it didn't disappoint!

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Tuesday night, they put it on the dyno and used their 850 cfm carb to test fire and run it in. Figured if it was gonna window the block, they might as well know that before I took a day off work. After a little tuning and timing changes, it ran out to 645HP on 110 octane race gas.

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When I brought the Holley Sniper to them today, we installed it, put in some 93 pump gas, and played with the tuning. Peak power at 635HP!

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This particular pull went to 7300 where it was STILL making great power. I don't plan to run it that high, but knowing it's strong and stable enough to do it is a great feeling.

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On another pull, we started at 3700, and it made 500 lb/ft of torque. This thing is gonna be a monster. And this year is gonna be fun!
 

Burninrock24

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Thats badass!! I bet that thing sounded amazing at 7300. How much in total do you think you have into this engine? It's a pretty tempting setup with those numbers.
 

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