Looking for feedback on 416 w/TFS 225 dyno
Mod list:
SDPC 416
TFS 225
243/247 ~.620 LSL lobes
LG Pro Headers
Stock Ti
Vararam
42lb injectors
LPE 255lph
3.90 gears
ported FAST 90mm
ported LS2 tb
11:1 compression
Centerforce Dual Friction clutch
Centerforce 12" flywheel
Red line (478/459) was with a 238/242 113+2 ~.600 XER cam.
Blue line (485/455) is the cam listed above.
Results have been duplicated by two different tuners on three different dynos. I have talked with a couple vendors that suggest the headers are holding me back. However, I swapped cams based on the recommendation of a vendor and that gained me a whopping 7hp.
Here is the SAE graph with both cams.

STD graph
Last edited by potac; Apr 24, 2009 at 01:00 AM. Reason: Updated graphs
Seems like the compression might be lower than expected.I just finished a 418 ci with a 418ci TFS 225's 11.8-1 comp and a smaller 236/238 Cam with the same mods and made 490hp/475 torque on a mustang dyno which peaked at 5900rpm due to the small cam.
I'd agree with Slowhawk the bigger header, better catback or maybe cutouts at the end of the midpipes. I would say upgrading to the 92mm ported fast will probably not net much of a gain. You could have a speed density tune and put a pipe in place of the MAF and thats shown a average of 5-10hp.
BTW, according to my math your compression is right around 10.72:1 knowing how SDPC sets up their shortblocks.
Let me go look on the dyno and see if I can find my old graph and Ill post it up.
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Looks like headers and cutouts may be the next mod on the list.
I think the heads were milled to 65cc, the pistons have a -10cc dish, and the head gasket was either .052 or .054". Is there an "easy" way to check compression to verify? Did that setup you built use 1-3/4" headers?
Do the math again.
I wouldn't worry about the LT's. LG's been saying for a long time that their 1 3/4 LT's make more power than 1 7/8. They even posted a bunch of dyno charts to prove it.

On a side note, the Tick adjustable master cylinder works as advertised. Before it was installed, I could not shift above ~5500rpms. Now, every shift is smooth and easy. Great mod!
Sorry Kevin, gotta clarify for you. LG posted numerous charts showing there 1 3/4 headers outperform the competitions 1 7/8 in making low end torque, while only losing 1 or 2 hp up top.
To the OP, your setup is bad ***, but is very soft on the bottom end. Considering you are using a slightly more aggressive cam and better flowing heads, also have 14 more cubes I am surprised at your results. Gears lose a couple hp, and you are missing a ud pully and ewp. With that being said I'd say your h/c selection with the 416 should be making in 525 rwhp 500 rwtq range. My little 402 did 517.3 and 513.8 rwtq. I would suggest you have your intakes inlet opened to 95 mm's and swap tb's to a rev extreme 95 mm tb. Terry Lewis can hook you up on the tb. When I swapped from ls2 90 mm tb to rev's 95mm I picked up 7 rwhp and 17 rwhp. Your catback is holding you back as well. What kind of car is this motor in? If its a vette then consider LGM's big 3. It flows very well. I picked up a nice amount of hp/tq vs my old bullets. Also the sound is a little more tolerable. I can hear my stereo and no more headaches lol. Sorry for the long rambling post, but I am just trying to help.
Please feel free to PM if you have any particular q's about my posted opinions, or my setup. Maybe we can figure it out.
More info needed to figure you compression
Head gasket thickness ?
Pistons -cc's
Heads cc size
Bore/Stroke
Sorry if I missed it but please repost for my benefit.
i did 510 through a 5200 stall, 9 inch and slicks.
id expect the dyno #'s to be quite a bit higher for your setup.
have you ran it at the track?
dyno dont mean jack, IMO.
good tuning adgent, but you cant base what the car runs off a #.
06 A4 GTO
416 LS3
3.91 gears
built tranny
3200 stall
236/238 cam (VRX5, shout out for Vengeance
)11.3 compression
2.5" catback (I dropped the catback for a pull and didn't gain any power)
ported fast 92
TFS 235
500/492
i did 510 through a 5200 stall, 9 inch and slicks.
id expect the dyno #'s to be quite a bit higher for your setup.
have you ran it at the track?
dyno dont mean jack, IMO.
good tuning adgent, but you cant base what the car runs off a #.
Nice numbers on your setup. How does the stall affect the driveability of the car?
06 A4 GTO
416 LS3
3.91 gears
built tranny
3200 stall
236/238 cam (VRX5, shout out for Vengeance
)11.3 compression
2.5" catback (I dropped the catback for a pull and didn't gain any power)
ported fast 92
TFS 235
500/492

