Jon Kaase Boss 429

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Supposedly, early in the development of the 71 Mustang, one of the design parameters was to make room for inclusion of the BOSS 429. The other runours are that the 429 CJ and SCJ twins were to go on a growth plan to produce a 460 variant in 72 and a 501 cube version by 73. Of course we all know that was derailed.

Can you imagine? a factory-installed BOSS 429 in a 71, or a factory 501 Super Cobra Jet in 73? Sure would have been awesome...

 

Finmach

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I managed to squeeze it down between the original shock towers.

But there is not much space left.

It is a Boss 572.

// Thomas
Not much space to waste, but the exhaust ports are nicely downwards compared to std. port location 429/460 exhaust ports. Are you going to fabricate the headers or gonna use the Ford Powertrain Applications 429 Boss headers? I've got also a A460 block, 4.500" forged crank, rods only waiting for the correct moment to get the Jon Kaase B9 heads. Boresize is not determined yet, but I've got to beat my friends Kaase made Boss 598 cid, so 4.625" can be expected. With 4.625" bore and 4.500" stroke I'll buy two "302 cid" badges and install one on both fenders :D

Supposedly, early in the development of the 71 Mustang, one of the design parameters was to make room for inclusion of the BOSS 429. The other runours are that the 429 CJ and SCJ twins were to go on a growth plan to produce a 460 variant in 72 and a 501 cube version by 73. Of course we all know that was derailed.

Can you imagine? a factory-installed BOSS 429 in a 71, or a factory 501 Super Cobra Jet in 73? Sure would have been awesome...
'71 shocktower factory made notches are there for purpose, Boss 429 valvecovers will fill them nicely like does the 427 SOHC. 429/460 is relatively easy for growthing the cid, since the stock 429 stroke is small blockish 3.590", with 4.140" stroke and 0.030" overbore you're allready at 501cid. 429/460 are commonly bored safely to 0.080" so there would have been plenty of meat on the table with bigger overbore. Guy from Finland built app. 20 years ago a 1971 HT Mustang as factory "highway catch car", it was equipped with nice factory OEM parts using 460 cid which really hauled the Mustang. Whole car was built with Ford OEM parts so that it could be made by Ford back the day. It's still sporting the same 460 cid and original paint from the 1971.
 
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Thomas

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Yes I bought the headers from Stan at FPA, but had to modify them a little bit. Because they were designed for 69/70.

// Thomas

Stan 008.JPG

 

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Yes I bought the headers from Stan at FPA, but had to modify them a little bit. Because they were designed for 69/70.

// Thomas
Nice looking headers. Should be sweet ride. What kind of hp-levels are we talking about? Where in Sweden do you live? Are you familiar with Unik Racing? They make really sweet EFI or 4xweber intakes for B9 engines - just a thought. Would look racy between the wide valvecovers.... :)

 

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Nice looking headers. Should be sweet ride. What kind of hp-levels are we talking about? Where in Sweden do you live? Are you familiar with Unik Racing? They make really sweet EFI or 4xweber intakes for B9 engines - just a thought. Would look racy between the wide valvecovers.... :)

Yes, I know the Unik racing, My buddy has a stack injection on a 351c from him. But if I buy one it will be from Kaase.

(I live in Motala)

// Thomas

USB 780.jpg

 

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Motala is close to Västerås app. 150 miles or so, are you planning to visit Big Power Meet 2015? We're there this summer with '68 428 XL500 Fastback Galaxie, I would loved to see your ride. If you're having a spare time at the 1.st of August 2015 you're welcomed to Finnish Ford Nationals at Alastaro Racing Circuit, so I hope you're having an od-tranmission :)

How did you Thomas built the brake booster? Did you used the angled spacer or something else?

For the original topic, the '71-'73 Mustang is very good platform to Boss 429 engine since the enginebay can swallow the huge engine.

 

Thomas

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Motala is close to Västerås app. 150 miles or so, are you planning to visit Big Power Meet 2015? We're there this summer with '68 428 XL500 Fastback Galaxie, I would loved to see your ride. If you're having a spare time at the 1.st of August 2015 you're welcomed to Finnish Ford Nationals at Alastaro Racing Circuit, so I hope you're having an od-tranmission :)

How did you Thomas built the brake booster? Did you used the angled spacer or something else?

For the original topic, the '71-'73 Mustang is very good platform to Boss 429 engine since the enginebay can swallow the huge engine.
No, I'm not going to Power Meet anymore .I have been there a few times, and that's enough for me. To much people.

The power brake booster I had to adjust a little sideways and tilt to the side, and mount a smoother brake master cylinder. So now I have just over 1/4 "distance from the valve cover.

 

Finmach

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No, I'm not going to Power Meet anymore .I have been there a few times, and that's enough for me. To much people.

The power brake booster I had to adjust a little sideways and tilt to the side, and mount a smoother brake master cylinder. So now I have just over 1/4 "distance from the valve cover.
That is a good way to use the original Style booster. What booster did you used? One guy made a hydraulic booster taken from a Cobra Mustang (if my memory serves me correct). Two of my buddies are using the rrs booster which is intact with the pedal assembly - It's beautiful piece plus you can get the barrel (booster) away to be able to have clean firewall.

I hear you from the Big Power, its HUGE event. We're for the first time at the hot rod meet nearby. There were beautiful cars, built hot rods and big park to hang with the buddies and decent tolerable amount of people. Of course we're every night at Autotek, there were some serious street cars visiting the garage as usually.

Absolutely great thing to have big boss going to big pony! Keep us posted Thomas.

 

Thomas

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IMG_0411.JPG Finally,, the hood getting ready for paint!
 
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