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S197 BOSS 302 Race Car Build Thread Build Thread Profile - S197 Mustangs

ArizonaBOSS

Because racecar.
Moderator
8,512
2,310
Arizona, USA
Well, guys, it's been a bit of a hiatus from this thread (some COVID-inflicted, some self-inflicted). After the prior update I ran a weekend at Chuckwalla in February 2020 where I was on my way to a class win, but had a brain fart late in the race and nearly took out a SPECE46 I was lapping--destroyed (another) splitter in the process and punctured the radiator. I managed to get the car all wrapped up for a local March 2020 event where I took two wins in-class, then discovered a massive exhaust leak on the scales after the final race. Turns out the "spike" inside the header had decided to separate from the rest of the assembly...

We're not 100% sure why the header failed, but the best theory is the solid motor mounts not giving the vibration anywhere to go. I purchased a set of new headers (ARH, this time) and had the Kooks ones repaired and sold. I had my fabricator friend install a couple of flexible bellows on the new X-Pipe to help with the vibrations in the future.

Anyways, with the motor basically having to come out of the car to get the header repaired, I decided after 5 seasons it was time to refresh it. Then COVID lockdown hit at the end of March and I kind of lost all motivation to actually get the engine out of the car. By the time I cared again, it was June. I was hoping to get the engine rebuild done locally in a month or two and be ready to race by September 2020--but it turns out that was a wishful estimate, as I didn't get the engine back from the builder until February 2021. On the plus side, I saved a lot of money not racing the rest of 2020. If the motor ever needs to be worked over again I'll get a crate engine and save myself the schedule pain.

The good news is that the refreshed engine is back in the car, and makes a nice 465hp to the tires. We had the break-in done a couple weeks ago at Chuckwalla and everything ran great! Here are a couple videos from the weekend...


 

cholmes1

400lb Gorilla
271
136
Denver, CO
Congrats on getting back out there. Can you share what mods were done to the engine to achieve the 465 NA RWHP?

Knowing you in the past you consistently steered towards reliability I am curious what parts were chosen and why.

Thanks
 

ArizonaBOSS

Because racecar.
Moderator
8,512
2,310
Arizona, USA
Congrats on getting back out there. Can you share what mods were done to the engine to achieve the 465 NA RWHP?

Knowing you in the past you consistently steered towards reliability I am curious what parts were chosen and why.

Thanks
Really nothing crazy--the key parts are effectively the same as my last build. Boss heads, L&M intake-only cams, forged shortblock, CJ intake, VMP 67mm twin TB, Ford Racing air intake tube and filter.

In this go-round, I had the heads polished further and also had bronze valve guides installed, along with machining the seats and adding larger valves for more airflow. I figured this would get me some extra power but apparently not, as the motor did basically exactly the same as my last one, when it was fresh. But at least it has fresh valve guides and seals now.

For reliability's sake, I installed the Archetype Racing oil-balancing kit, 5.2L valve lash adjusters, and GT4 secondary timing chain guides. Probably no power to be had there, but with the amount of time we spend in 6500+ RPM it makes sense for me.
 
3,574
2,845
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Really nothing crazy--the key parts are effectively the same as my last build. Boss heads, L&M intake-only cams, forged shortblock, CJ intake, VMP 67mm twin TB, Ford Racing air intake tube and filter.

In this go-round, I had the heads polished further and also had bronze valve guides installed, along with machining the seats and adding larger valves for more airflow. I figured this would get me some extra power but apparently not, as the motor did basically exactly the same as my last one, when it was fresh. But at least it has fresh valve guides and seals now.

For reliability's sake, I installed the Archetype Racing oil-balancing kit, 5.2L valve lash adjusters, and GT4 secondary timing chain guides. Probably no power to be had there, but with the amount of time we spend in 6500+ RPM it makes sense for me.
How tight are you turning it?
 

ArizonaBOSS

Because racecar.
Moderator
8,512
2,310
Arizona, USA
I assume you mean RPM-wise--which I've limited to a "modest" 7800 RPM. I used the "regular" B302 valvesprings again this time--for more revs than that I would have wanted to go with the PAC1234X setup from the FP350S like @captdistraction did on his build.

The engine isn't making any more power up there, from what the dyno says, though--so no real benefit for me. I figured with more airflow from the valves, there would be more up-top power, but apparently not. Those heads must be pretty damn dialed-in from the factory.
 
3,574
2,845
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I assume you mean RPM-wise--which I've limited to a "modest" 7800 RPM. I used the "regular" B302 valvesprings again this time--for more revs than that I would have wanted to go with the PAC1234X setup from the FP350S like @captdistraction did on his build.

The engine isn't making any more power up there, from what the dyno says, though--so no real benefit for me. I figured with more airflow from the valves, there would be more up-top power, but apparently not. Those heads must be pretty damn dialed-in from the factory.
Same deal here, mine peaks at 7500 rpm but I need 500 more rpm to get to 3 corners in a row and I'm hitting 7985 to get there. As I dial the car (and get used to driving it) and also get the ABS working I expect that # will go up so I am probably going to swap out the 4:10's for 3:90's. Shaun says just wind it up, its wont blow....and I trust him but man it makes me nervous. Check the video on my thread....you can see me go for the shifter and then let it spin up instead....makes me nervous as hell but so far its held together.
 

ArizonaBOSS

Because racecar.
Moderator
8,512
2,310
Arizona, USA
Same deal here, mine peaks at 7500 rpm but I need 500 more rpm to get to 3 corners in a row and I'm hitting 7985 to get there. As I dial the car (and get used to driving it) and also get the ABS working I expect that # will go up so I am probably going to swap out the 4:10's for 3:90's. Shaun says just wind it up, its wont blow....and I trust him but man it makes me nervous. Check the video on my thread....you can see me go for the shifter and then let it spin up instead....makes me nervous as hell but so far its held together.
Which corners at LS? I love revving the hell out of my engine but there are times when a gear up works better (but doesn't seem as sexy).
 

Dave_W

Cones - not just for ice cream
223
222
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
Really nothing crazy--the key parts are effectively the same as my last build. Boss heads, L&M intake-only cams, forged shortblock, CJ intake, VMP 67mm twin TB, Ford Racing air intake tube and filter.
After seeing the dyno graphs from you and wwilde001 (https://trackmustangsonline.com/threads/cobra-jet-intake-and-cams-on-boss-motor.8584/post-185364 and the following post), a CJ intake is on my list of eventual upgrades for my '13 Boss, and I'm trying to gather info on package variations. Any particular reasons for the VMP 67mm vs the Ford 65mm vs VMP 69mm? And the Ford vs PMAS intake tube? Thanks.
 

ArizonaBOSS

Because racecar.
Moderator
8,512
2,310
Arizona, USA
I downshift to 3rd in 2 and carry it all the way to 11.

Oh. I would be doing a bit more shifting. Up to 4th between T4 and T5 (then back down to 3rd entering T5), probably up to 4th after T6, back to 3rd (or 2nd) going down the Corkscrew, then back up to 3rd...tap the limiter in 3rd before 10 if necessary.
After seeing the dyno graphs from you and wwilde001 (https://trackmustangsonline.com/threads/cobra-jet-intake-and-cams-on-boss-motor.8584/post-185364 and the following post), a CJ intake is on my list of eventual upgrades for my '13 Boss, and I'm trying to gather info on package variations. Any particular reasons for the VMP 67mm vs the Ford 65mm vs VMP 69mm? And the Ford vs PMAS intake tube? Thanks.
The VMP twin 69mm didn't exist at the time I did my build, the 67 was a "more flow" option vs. the 65, and less problematic than the CJ Monoblade. I am actually considering switching to the VMP twin 69, now that you have brought this up...
Ford intake option was fire-and-forget, and looks professional. PMAS looked like someone wrapped a 2L bottle in silicone and sold it for $400. But, it might make more power.
 
3,574
2,845
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I suppose...sorry. His video on your thread through me a curve. Or the reciprocal of that. Either way I was confused, but that doesn't take much effort... 🤣.
I do wear a fire suit for races.
This was just a test day. Nobody ever catches fire on a test day...oh wait....yes I do.


59534433_10157251755638535_1242807825718050816_n.jpg
65440186_10157415456748535_3962297735050166272_n.jpg


Yes I'll be doing some more shifting.
My tuner says to wind her up to 8k so I did but it makes me nervous so I'll be using 4th more this weekend.
If that doesn't feel good I'll be making a rear gear change......stay tuned.
 

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