Disappointing 408 Results
Disappointing 408 Results Here's the details
TSP 408 shortblock
Stage 3 tsp LS6 plus hand worked locally milled 59.5
YT rockers 11.64scr 8.54 dcr
Fast 92/92
24x/24x 62x/6xx 112+2
EWP
6speed thru TEX clutch
4.11 9"
Numbers 467hp 445tq
cutout open 476hp
Dynoed on dynojet by Geoff at EPS Great Guy lot of good info!
Thinking about going to TFS235's what are your thought on swicthing heads and dyno results?? Sorry dont have the graph Geoff didnt have printer on dyno computer!
GRAPH ON POST #22 THANKS MACH1
TSP 408 shortblock
Stage 3 tsp LS6 plus hand worked locally milled 59.5
YT rockers 11.64scr 8.54 dcr
Fast 92/92
24x/24x 62x/6xx 112+2
EWP
6speed thru TEX clutch
4.11 9"
Numbers 467hp 445tq
cutout open 476hp
Dynoed on dynojet by Geoff at EPS Great Guy lot of good info!
Thinking about going to TFS235's what are your thought on swicthing heads and dyno results?? Sorry dont have the graph Geoff didnt have printer on dyno computer!
GRAPH ON POST #22 THANKS MACH1
Last edited by LS1ROPER; Oct 15, 2009 at 07:21 AM.
TECH Enthusiast
Joined: Apr 2007
Posts: 629
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From: Charlotte, NC
You will definitely pick up a lot with the TFS 235's, the question is how much? Won't know until you do it 
I will say I think its worth it and their are a few recent 408's with similar mods as yours making 540-550rwhp but those are Vettes with 4.10's. I think 530 is within reason with your setup depending on how well the cam matches up to the heads. Also make sure the valvetrain is set up properly.
Can you post the graph? Its definitely very low for a 408 with those parts. What is the exhaust setup?
I will say I think its worth it and their are a few recent 408's with similar mods as yours making 540-550rwhp but those are Vettes with 4.10's. I think 530 is within reason with your setup depending on how well the cam matches up to the heads. Also make sure the valvetrain is set up properly.
Can you post the graph? Its definitely very low for a 408 with those parts. What is the exhaust setup?
Unless the head porter has a lot of experience in LS style heads and have proven results time and time again, I'd say the heads are to blame for your low numbers. All your other mods look good.
With a good ported 243 head, you should hit 500 RWHP with no problem.
With a good ported 243 head, you should hit 500 RWHP with no problem.
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for real. i would think that thing would easily put down 520 ish. 
If it were my motor and I was sure the tune- afr, timing ect. was right I would look really hard at mechanical, leak down test, cam timing (with a degree wheel not just dot to dot)