2002silverz28matt

when you guys made the swap to a th400 or 350, did you notice a significant drop in power? How much? What kind of stall are you using? I have an 8 inch 5200 in a th 400 and I think it is robbing me blind of power on the dyno, or sometin is going on. Old 346 motor 235/243 cam ported 243's ls6 intake full bolt ons 4k yank stall 4l60e. New motor 383 11.75 cr 242 250 cam ported 243's ls6 intake full boltons th400 8 inch 5200 stall. Old motor made 415 to the tire, new motor made 375 to the tire. I am down 40 horse right there, but we cant forget I put a bigger cam in, bigger motor in, and way more compression!!! I cant complain about the tune or how the car runs, but I mean damn that seams low. This was on the same dyno. I would think this new motor should make 40-50 more hp than the old. So there is a good 80 hp MIA. I am sure the tranny will eat some but damn, i think there is somethn else goin on here. I will take a couple pics here shortly ofthe graphs and post them. The intake will hold me back some, but it shouldnt loose power with the big motor, just not gain as much out of the motor. What do you guys think??

new motor
http://i752.photobucket.com/albums/x...383dyno005.jpg

old motor
http://i752.photobucket.com/albums/x...4/DSCN0932.jpg

LIL SS

iTrader: (9)

Was the 415rwhp with the 60e locked or unlocked? Obviously your not locking the 400.

Also a 400 is more similar to an 80E where a TH350 is similar to a TH350. There is a decent loss between a TH350 and TH400, just like there is a decent loss between a 4L60E and an 80E. In a sense, you went from a TH350 with lock up to a 400 with out. Or a 60E to a non locking 80E. There will be a prety decent change in power.

Get it to the track and see what happens.

2002silverz28matt

Yes that dyno graph of the 60e is locked. The only reason I am comparing it to the unlocked 400 run is because at that time the old 60e was on its way out and slipping. It still put down 390 unlocked, but the graph had jumps in it due to slipping. I will see if I can find one of those graphs. When the car was cam only it put down 367.

I did take it to the track and made a few passes. I am just running street tires because I still have the 10 bolt. I am trapping dead on what it used to (113) and running a few tenths slower(mid 12's instead of low 12's with old setup) I dont care about et since I am on streets, just looking to compare mph. I mean the tune is good, af dead on all the way, I guess it is what it is, its just frustrating to see cam only 346's putting down better numbers than my bigger cam 383. I am hoping a fastbrings in big numbers. I know someone who ran this exact cam(I bought it from him) with a 383 11.0 cr with a 350 and a fast intake and put down 490he was running a 5000+ stall also. I guess I am just curious to see what other similar setups were running on the dyno

383vert

iTrader: (4)

I'd say your stall is eating the power... I have a 383 Ls1 and it has never been a real performer... It just hasn't...
I had ported 243's, Ms4, 1 7/8" l.t.'s, ported t.b., and a Ls6 intake with all the supporting mods. and only put down 435 rwhp on the same dyno. That engine combo also had 11.7:1 stat. comp. and was thru and a 7.5 rearend with 3.73's and a borla open exhaust plate.
The 383 just doesn't pick-up power like I hoped for... Or like the larger strokers do.
Sorry, bro. Just my $.02...

2002silverz28matt

Ya, I guess I was a little optimistic for the new setup. I still really like it, car feels strong and all, and now I dont have to worry about dominating the tranny or engine. Plus I plan on spraying the **** out of it anyway. Sounds like you have a very similar setup to me.

smok'nZ

iTrader: (160)

after i did the th400 swap my car felt slow i had 3 people in it but i wasnt pleased so i changed gears to a 4.10 and added a fast 102 instead of the 90/90 i had car felt 20x better

383vert

iTrader: (4)

Yep. Now I'm low comp. @ 9.6:1 hoping to go with some boost soon...
#'s in my sig. Yes, the car still runs great but it never will match the power of a 402+ c.i. with same combo... just how it is... wright?

The one thing I wish I would have done was try a Fast intake. But, too late now. I'm thinking if I don't get the blower/turbo soon I'm going to de-stroke the Ls1 and put it in my iron block Lq4... Of course with different pistons...

But, don't give up. I bet a set of tfs 220's (or better) and a ported fast with the right cam, you'll get the results your lookin for. Best wishes to ya. I'm sure I'll see you out... Maybe down here in the ljc...

383vert

iTrader: (4)

Are your heads cnc'd or hand ported? what valves? flow #'s?Just wondering also what exhaust set-up? I did pick-up @ 30 rwhp with a long merge y pipe and different convertor

2002silverz28matt

The numbers are the only thing I am not thrilled with, the tune and the work that was done to the car is great, plus the help with selling my old stuff. I have 1 7/8 american racing headers, no cats American Racing ypipe, magnaflow exhaust. The heads are texas speed prc stage 1 cnc ported 243's, here are the flow numbers

Lift
Intake Flow

Exhaust Flow

.200"
147 cfm

114 cfm


.300"
207 cfm

148 cfm


.400"
255 cfm

187 cfm


.500"
292 cfm

202 cfm


.600"
313 cfm

220 cfm


I was considering going to a nice tfs or afr head, but I mean I just cant justify that right now b/c these flow numbers are right up there with those high dollar heads, plus all the work of changing the heads. The fast and underdrive pulley are next, I will post the numbers. I plan on keeping the cam, I think 242 250 is big enough haha. For boost, I like the new D1sc with helical gears, I have a friend that is currently installing one on his bird. I think that should put you over 400 to the tire... Were you up at that car show in St Charles a couple weekends ago, I think I saw your car there?

s346k

iTrader: (4)

what brand stall?

due to its small diameter, the 8" stall would be most likely to provide efficiency vs the bigger sizes. also, what is done to the th400? what rpm do you shift at?

2002silverz28matt

It is a TSI racing stall. The th400 is a rmvb and tbrake, shift kit, deep pan, level 2. I shift at about 6500. The stall comes in on motor at about 4500, it will only stall over 5k on the brake.

383vert

iTrader: (4)

Yep... that was me...

I agree your cam and heads sound like a good combo. Fosho.
My old 243 set-up w/Ms4 that made 435, the heads were hand ported with stock valves flowing only 297 @ .600 and max exh. was like 227... So, your heads seem like a much better pair. I'm running a TSI stall and love it ,too. I'll agree that the fast and a fresh tune hopefully will be the fix... Keep us informed

AINT SKEERED

iTrader: (2)

i made 400 rwhp with my nova with and 8" converter that flashes to 4700,i made 400 rwhp through a th 350.
that converter will rob a lot of power but at the track it should really shine. street tires are holding you back big time. even mph if you had to peddle it out the hole

Zman420

iTrader: (18)

hmm, you seem down a little on power, but the bigger stalls and th400 will def. eat power on a dyno.
For example, my old setup was a stock Ls6 w/ bolt ons and 241 heads and put down 381 on a dynojet through a 6 speed and moser 9 in.
My new setup is a cam only stock bottom end ls6 with stock 243 heads,vic jr/4150 accufab, through a 9in 4000 neil chance and a rossler th400 and moser 9in. and it put down 388 on the same dyno..

So basically, adding a healthy size cam that was made by eps for this specific combo and better heads with a vic jr and accufab over a ls6 intake and stock TB just barely squeaked past where i was with the 6speed. Wich tells me the auto setup is probly eating around 60-80rwhp more then the 6-speed, if not more..

LIL SS

iTrader: (9)

I have never seen a box stock Vic JR make more power than an stock LS6 with ported throttle body. Actually, I have only seen them loose power.

Now if the Vic JR is ported that's another story. I have seen them gain a ton up top over an LS6 and even over a lot of ported Fasts.

Zman420

iTrader: (18)

well ill never really know what the difference is becuase i made too many changes to the car at once. But the bottle neck in my setup is definatly the heads and possibly the intake. I plan on working the heads and Intake over once I find a reason to pull the heads back off.. I was unemployed when I put the motor together and got my job back after it was already in the car, so i said screw it, and just ran with what I had.