Low 408 results?
Low 408 results? Car is a 98 TA M6 3.42 gears stock 10 bolt.
HKE 408
Probe Pistons
Stock 241 Heads Ported/Polished
Stock Compression
238/242 112+2 Custom Cam
Ls6 Intake
42lb injectors
Put down 440/435 on a dynojet.
Seems low for a 408.. any thoughts? Oh and rev limiter is 6600 they only brought it like 5800
HKE 408
Probe Pistons
Stock 241 Heads Ported/Polished
Stock Compression
238/242 112+2 Custom Cam
Ls6 Intake
42lb injectors
Put down 440/435 on a dynojet.
Seems low for a 408.. any thoughts? Oh and rev limiter is 6600 they only brought it like 5800
i saw 3 things in your 408 :
1- are your 241 heads realy flow good with high port velocity?
2- stock compression around 10:1 you should be 11:1 to 11.8:1 to make more power.
3- your cam is a little on the low side, it should be more like 244/248 to 248/254 or so.
1- are your 241 heads realy flow good with high port velocity?
2- stock compression around 10:1 you should be 11:1 to 11.8:1 to make more power.
3- your cam is a little on the low side, it should be more like 244/248 to 248/254 or so.
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
Yeah your heads and intake are holding you back. Probably mainly your intake and TB at present. Put the fast92/92 on and you should gain a good bit. Heads are probably 5-10% off the pace, but Im betting your intake and tb are the biggest bottle neck.
Trending Topics
I would do Fast 9X/9X and 1 7/8 headers (if you don't already have them) first and see where that puts you. If your power is still not where it should be I would look at a nice set of heads!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
if the dyno operator stopped the pull at 5800 on purpose, they dont know what they are doing with these cars.
ls6 intake is holding you back no more than 25 rwhp based on that cam/compression
ls6 intake is holding you back no more than 25 rwhp based on that cam/compression
IMO The numbers are great for your mods still have a lot left on the table.
compresstion, heads, intake , TB , cam, headers, RPM and tune.
wih these mods 490+rwhp shouldnt be a problem.
compresstion, heads, intake , TB , cam, headers, RPM and tune.
wih these mods 490+rwhp shouldnt be a problem.
i have very similar cam, and tsp ls6 stage 2.5 heads, with a fast 90/90 #s in sig. I just got some arh 1/78" long tubes to get ready for bigger heads and cam after next season. buying things slowly. I should jump to over 500rwhp with better heads, cam, exhaust. YOu are right on track with what you have now. The power is there uncork it when you get the money.
btw Zaccagnini, your dyno numbers look good for the mods you have.
Last edited by Abdullah; Nov 30, 2008 at 01:07 PM.
TECH Regular
Joined: Mar 2006
Posts: 471
Likes: 0
From: Rolesville, NC
TECH Addict
Joined: Jul 2002
Posts: 2,906
Likes: 0
From: Somewhere I Belong
A little bump in the compression (11:1 is a perfect mid point) by either changing head gaskets or swapping to a different cylinder head thats been milled would be a great starting point. I'd look into a "premium" set of cylinder heads if the money is available OR even a great "budget" head like TEA or ETP ported 243 castings if you're trying to save a little coin.
I'm sure that cam is just fine. There's no reason to try and stick a donkey dick cam in there. You'll just wind up being disappointed with the results. Also, there is NOTHING wrong with 1 3/4's on a 402/408 motor. Again, you'll go through all that hassle and spend all that time and money on nothing more than a "few" ponies upstairs and possibly negate all gains made by losing a **** load down low.
Heads and a little bump in compression. After that, see where you're at and then start considering the fast 90/90 or 92/92
I'm sure that cam is just fine. There's no reason to try and stick a donkey dick cam in there. You'll just wind up being disappointed with the results. Also, there is NOTHING wrong with 1 3/4's on a 402/408 motor. Again, you'll go through all that hassle and spend all that time and money on nothing more than a "few" ponies upstairs and possibly negate all gains made by losing a **** load down low.
Heads and a little bump in compression. After that, see where you're at and then start considering the fast 90/90 or 92/92
Thats about the same power my boost 402 was making pre turbos, 10.3:1 compression, stock Dart heads flow 300cfm, 236/242 cam, it made 451rwhp, so I put turbos on it and haven't looked back.
Those pistons must be dished? need more compression, cometic gaskets with tighter quench, depends on how those pistons setup, if they are at 0 deck, I would go with .040" gasket. Mill the heads down to 60cc.
and FAST intake
but pulls only went to 5800 or am I reading that wrong?
Those pistons must be dished? need more compression, cometic gaskets with tighter quench, depends on how those pistons setup, if they are at 0 deck, I would go with .040" gasket. Mill the heads down to 60cc.
and FAST intake
but pulls only went to 5800 or am I reading that wrong?
Last edited by Fraser@SpeedInc; Dec 1, 2008 at 11:24 PM.