99 F-250 V-10 4.10 gears 305/55R20 Terra Grapplers on weld evo Velociti 8's


I just got the truck back from the performance shop that managed to remove all the broken studs w/o taking the heads off.

I ran the factory exhaust until 80k, then I had the banks headers installed and all new studs except for two they could not get out at the Ford dealer.

Now at 160k I am running the Thorley headers and IMHO they are much better than the banks. I researched like crazy to find headers that had thicker wall tubes and good inside diameter on the tubes. Every thing I found was 16 ga stainless, except for the borla at 18 ga 304 stainless, and the Thorley's at 14 ga mild steel ceramic coated inside and out.

The Thorley headers are less noisey in the cab verses the banks, but still louder than factory.

They give the V10 a deeper sound than the banks for sure and the low end torque seems to be better than factory.

They also look great when new, I know they won't stay this shinny forever, but the ceramic coating look really slick.

They went on really easy according to the shop. The shop did have to fab a pipe that went from the thorley Y to the factory Cat, since Thorley did not send the right pipe for this. I guess 99's have a different y-pipe to cat setup verses all other years.

I will be having the truck tuned by one of the best shops in my area, as soon as I change the plugs and replace the COPs with the granatelli ones. I will get the dyno graph from the tune and post it here.

 

Thanks for the review, they sound great!!! The pics they sent me would show that an earlier V-10 with the cat pipe behind the crossmemeber would need a fab'd up pipe. Where did you get them from, Summit?

 

The shop I was working with bought them direct from Thorley I believe. The shop charged me $975 for them.

Nick at the Thorley 800 number was saying $900 for the set shipped to me, when I spoke with him.

 

Here are the dyno specs before and after tuning. This was done on a roller drum mass type dyno, if that makes any sense.

Fixed parameters
99 4x4 CC SB V10, Auto Trans, 161,000 miles, Thorley headers, Banks Cat-back, granatelli COPs, done in 3rd gear top speed limiter removed, 87 octane, 66 deg F, 7% humidity, and 28.93 in-Hg.


Stock calibration:
211 RWHP @ 4500rpm
320 RWTQ @ 2600rpm

Tuned performance:
220 RWHP @ 3750rpm
344 RWTQ @ 3100rpm

I will post the dyno graph info as soon as I can scan it in. They tuned the air to fuel mix from 15.24 to 13.4 and advanced the spark a bit. This new air to fuel is supposed to keep the exhaust temps down (prolong the life of my exhaust studs), increase fuel eff, and give more power.

 

900 bucks for 9 Hp. How is the fuel mileage???

 

The 9 hp are purely from tuning. The Thorley's were on the truck for the baseline and tuned.

Before the Thorley's I had the banks headers and they were noisey. The $900 was to reduce noise, 14ga mild steel coated on both sides(Thorley) verses 16 ga 409 stainless(banks).

It's been doing nothing but snowing here and I have not done any highway driving, so the verdict is still out on mpg.