Exhaust 351 Swap Headers And X/h-pipe (bolt-in Sn95 Solution)?

WhiteCobra95

Mod Dude
May 2, 2006
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Can someone who either owns an SN95 with a 351 swap or has done the swap please help me out with an exhaust question.

I'm helping a friend install a 351 into his 1994 GT hardtop to replace his (tired - 200k miles) stock 302. The 351 is a mild-build roller cam motor with ported iron GT40 heads. The car is going to be a summer daily driver and will be smog inspected.

I'm looking for shorty headers and a matched H or X pipe with cats that we can bolt right in. Can anyone recommend a brand or part numbers that you've used and had good results with? (He's trying to avoid exhaust fabrication work if possible.)

Long tubes might be another option, but I think that's more difficult with his requirement for having cats and a bolt-in installation.

Several years ago when I was considering a 351 swap for my car, BBK recommended their shorty Fox 351 swap headers, P/N 1511 / 15110, and told me that they will bolt right up to their SN95 mid-pipes, but I would like to hear from someone who can actually confirm that this mix-match of parts works.

He already has a Maximum Motorsports steering shaft installed, in case that makes a difference on the header fitment for the driver-side.

Thanks!
 
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I can say both from my "research" and personal experience that the only difference between SN and Fox 5.0 shorty headers and long tubes have to do with EGR and the bell housings specific to each platform.

With short tubes, the only difference is EGR. As you know, '94-'95 5.0 cars take the EGR feed directly from the primary tube for the #3 cylinder. Foxes don't have this as the EGR is internal to the cylinder heads. If the car is to be smog tested, then this may be an issue unless he is planning to convert to a Fox-style internal EGR.

With long tubes, the only difference in addition to the aforementioned EGR is the primary tube routing on the driver side header due to the different clutch fork position between the Fox and SN 5.0 cars with manual transmission. The clutch fork on Foxes is closer to 9 o'clock while it's closer to 7 o'clock on the SNs.

I don't know anything about how the MM shaft affects clearance.
 
02 281 GT,

Thank you very much for the detailed information. This is exactly what I needed!

The EGR detail is a great point. We'll either have to use the internal Fox system or weld a fitting onto the #3 runner and fabricate the pipe to the EGR valve since the SN95 302 tube will be way too short and misaligned on the 351.

Thanks again, I really appreciate the help! =)
 
The different routing of the driver side primary tubes for long tubes also applies to short tubes with the h-pipes. The driver side pipe is also routed differently between '94-'95 5.0 cars compared to Fox 5.0s for the same reasons as long tube headers. So if you go with Fox short tube swap headers, you may run into problems using a Fox h-pipe if you're planning to use the stock '94-'95 bell housing. It would be better to run the '94-'95-specific h-pipe in this case (especially since BBK already confirmed it would bolt right up).
 
Thanks once again! :) That's good info about the mid-pipes. I know about the difference in hanger bars, but I didn't know about the clutch fork changes. That makes perfect sense and explains whey the aftermarket had to create different parts for those years.

He's planning to order the '94/'95 mid pipe with cats, so if the flanges on the BBK Fox swap headers dump in the same spot we should be okay. I can't think of too much worse than getting the engine in and realizing that the exhaust won't fit!

Thanks again for your help and your input. The aftermarket is definitely cutting back on parts for the 5.0 SN95s, so it's good to document these details somewhere in case the SN95 specific parts go away entirely.
 
I thought I would post this in case anyone else is interested in 351 swap info.

I recently found a part number for Hooker SN95 351 swap headers:
6133-HKR (painted)
6133-1HKR (ceramic)

They are quite a bit more expensive than the BBK 351 swap shorties, but the BBK swap headers don't seem to get very good reviews on other forums in terms of fit or quality.

The other nice thing about the Hooker shorties is that they're supposed to mate up to a factory H-pipe or aftermarket H/X pipe that uses the stock flange location. My experience with the 5.0 SN95 BBK shorties is that they've turned the flanges a mall bit, so only their own H / X pipes will seal up properly.

I had Hooker supercomp long tubes on my big block drag car and they were very nice headers, but I'm not sure if they were daily-driver quality (thin tubing and thin flanges). Please chime in if anyone out there has used these Hooker swap headers and what you thought of them in terms of fit, finish, and durability. $565 is a lot of $$$ for coated shorty headers, unless they're extremely nice / well-made pieces!