Can a 402 get me 550rwhp?
09-21-2005, 04:51 PM
#1
Launching!
Thread Starter
iTrader: (6)
Join Date: Mar 2005
Posts: 227
Likes: 0
Received 0 Likes
on
0 Posts
Can a 402 get me 550rwhp? ok this is what i want..i want a 402 that will give me 550rwhp N/a..what will it take? obviously a set of AFR milled heads and a big *** cam, etc..what will my compression need to be around..and do u think this goal is possible using pump gas? whats the max compression i can run on pump gas...thanks!
09-22-2005, 04:25 AM
#4
TECH Regular
iTrader: (1)
Join Date: Nov 2002
Location: Howell Mi.
Posts: 402
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 5.3litre
ok this is what i want..i want a 402 that will give me 550rwhp N/a..what will it take? obviously a set of AFR milled heads and a big *** cam, etc..what will my compression need to be around..and do u think this goal is possible using pump gas? whats the max compression i can run on pump gas...thanks!
How much can you tolerate
Big heads and solid roller cam race fuel ............
11.2 is about all on 93 octane
A nice 402 would make 450-75 and a 427 + cubes ,is what you need with some big heads from ET Performance .
Do your homework
09-22-2005, 08:50 AM
#5
TECH Fanatic
iTrader: (6)
Join Date: Apr 2005
Location: Rural Retreat VA.
Posts: 1,552
Likes: 0
Received 0 Likes
on
0 Posts
Mike Johnson's
2000 Pewter Trans Am - 6 Speed
517 RWHP!
LS2 Block
SLP 402 rotating assembly
AFR 225 Heads
F.A.S.T. Intake
and more....
Don't know the cam specs or any of the details, but I'm sure most people around the Charlotte NC area know the car.
2000 Pewter Trans Am - 6 Speed
517 RWHP!
LS2 Block
SLP 402 rotating assembly
AFR 225 Heads
F.A.S.T. Intake
and more....
Don't know the cam specs or any of the details, but I'm sure most people around the Charlotte NC area know the car.
09-22-2005, 11:00 AM
#6
TECH Addict
iTrader: (8)
Join Date: Apr 2003
Location: Honolulu HI
Posts: 2,513
Likes: 0
Received 0 Likes
on
0 Posts
this is what confuses me...why would you spent the money on a 402 to make only 450-475 hp, when a h/c 346 can do that with the right combo and tune?? is it solely for the extra torque? and is 50lb ft worth 3-4 thousand dollars?? nitrous would be cheaper and you can run a safe 75 shot- 100 shot...i would expect 500+ out of a bigger cubed engine if a 346 can get 430 -460. am i wrong in my assumption?
09-22-2005, 11:05 AM
#7
Banned
iTrader: (19)
Join Date: Jun 2005
Location: chitown
Posts: 1,879
Likes: 0
Received 0 Likes
on
0 Posts
you can get 550 to the wheels n/a on pump gas w/ a 6spd... but you'll need a huge cam and great heads........ i'm thinking the new e.t. performance heads would make it there.
is trans is in the car???
is trans is in the car???
Trending Topics
09-22-2005, 11:11 AM
#8
You can go much higher than 11.2:1 on 93 octane, but it depends on timing and the cam. Big cams "bleed off compression," or lower the dynamic compression ratio. That's why big cammed cars don't usually make a lot of low end grunt--no cylinder pressure at low RPMs.
With that said, 550 is a bit of a stretch on a 402, because the bore is only 4 or 4.005". I think 530rwhp would be easy to get without going too crazy.
Try this:
-402 LS2 Shortblock
-AFR225s milled .036" to 66cc
-Cometic .040" compressed MLS gaskets
-Morel or Comp "R" Lifters
-Comp Cams XE-R 244/248 .612"/.615" 114+1 LSA Camshaft or Comp Cams LSK 243/247 .653"/.656" 114+1 LSA Camshaft (both have similar ramp rates, but the LSK lobes have more duration at .200" but either will make streetable power)
-Port matched FAST LSX90 intake manifold and Nick Williams 90mm throttle-body
-QTP 1-7/8" High Velocity Merge Headers
-True Duals
Should be good for about 530rwhp easily. If it were a 427 with a 4.125" Bore, I'd say the same combo would net you 550rwhp with no problem. It will have great street manners and make good torque as well. The compression comes out to about 12.1:1 and the DCR is about 8.45:1 which is fine for 93 octane. With the cam setup like it is, I think 550 could be possible.
If you need to run less octane or don't want to run that high of a SCR, you can mill the heads .024" for 68cc and you'd have 11.75:1 with a DCR of 8.25:1, but you'll be giving up a little bit of torque. You could play around the the LSA and advance, but the 244/248 on a 114+1 will keep the intake valve open longer than if you go with a 112+1. That will make a little more horsepower uptop and get you closer to 550rwhp. But, if you want a SCR of 11.75:1 instead of 12.1:1, going to a 112+1 LSA will give you a DCR of 8.4:1, making for some nice torque, still giving you around 530rwhp, and a chopier idle.
Hope that helps.
With that said, 550 is a bit of a stretch on a 402, because the bore is only 4 or 4.005". I think 530rwhp would be easy to get without going too crazy.
Try this:
-402 LS2 Shortblock
-AFR225s milled .036" to 66cc
-Cometic .040" compressed MLS gaskets
-Morel or Comp "R" Lifters
-Comp Cams XE-R 244/248 .612"/.615" 114+1 LSA Camshaft or Comp Cams LSK 243/247 .653"/.656" 114+1 LSA Camshaft (both have similar ramp rates, but the LSK lobes have more duration at .200" but either will make streetable power)
-Port matched FAST LSX90 intake manifold and Nick Williams 90mm throttle-body
-QTP 1-7/8" High Velocity Merge Headers
-True Duals
Should be good for about 530rwhp easily. If it were a 427 with a 4.125" Bore, I'd say the same combo would net you 550rwhp with no problem. It will have great street manners and make good torque as well. The compression comes out to about 12.1:1 and the DCR is about 8.45:1 which is fine for 93 octane. With the cam setup like it is, I think 550 could be possible.
If you need to run less octane or don't want to run that high of a SCR, you can mill the heads .024" for 68cc and you'd have 11.75:1 with a DCR of 8.25:1, but you'll be giving up a little bit of torque. You could play around the the LSA and advance, but the 244/248 on a 114+1 will keep the intake valve open longer than if you go with a 112+1. That will make a little more horsepower uptop and get you closer to 550rwhp. But, if you want a SCR of 11.75:1 instead of 12.1:1, going to a 112+1 LSA will give you a DCR of 8.4:1, making for some nice torque, still giving you around 530rwhp, and a chopier idle.
Hope that helps.
09-22-2005, 11:59 AM
#9
TECH Senior Member
iTrader: (10)
Join Date: Nov 2001
Location: Gainesville, Denton TX
Posts: 8,766
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ninobrn99
this is what confuses me...why would you spent the money on a 402 to make only 450-475 hp, when a h/c 346 can do that with the right combo and tune?? is it solely for the extra torque? and is 50lb ft worth 3-4 thousand dollars?? nitrous would be cheaper and you can run a safe 75 shot- 100 shot...i would expect 500+ out of a bigger cubed engine if a 346 can get 430 -460. am i wrong in my assumption?
a 408 with decent heads and cam should be a minimum of 500.
the tq is insane on a 400+ motor, and the power curves are less of a peak, smoother...
I remember reading a few weeks ago a 408 w/ 241s (un ported) that went in the 460-70 range... Now, throw some heads on there and who knows what will happen.
460ish at 6200rpm or there abouts i believe, shows how much the heads are choking the motor.
09-22-2005, 12:15 PM
#10
TECH Fanatic
iTrader: (35)
Join Date: Sep 2004
Location: Maryland/Illinois
Posts: 1,660
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Brandon
not at all.
a 408 with decent heads and cam should be a minimum of 500.
the tq is insane on a 400+ motor, and the power curves are less of a peak, smoother...
I remember reading a few weeks ago a 408 w/ 241s (un ported) that went in the 460-70 range... Now, throw some heads on there and who knows what will happen.
460ish at 6200rpm or there abouts i believe, shows how much the heads are choking the motor.
a 408 with decent heads and cam should be a minimum of 500.
the tq is insane on a 400+ motor, and the power curves are less of a peak, smoother...
I remember reading a few weeks ago a 408 w/ 241s (un ported) that went in the 460-70 range... Now, throw some heads on there and who knows what will happen.
460ish at 6200rpm or there abouts i believe, shows how much the heads are choking the motor.
09-22-2005, 01:32 PM
#12
TECH Senior Member
iTrader: (4)
Join Date: Dec 2003
Location: Arlington TX
Posts: 5,276
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Brandon
not at all.
a 408 with decent heads and cam should be a minimum of 500.
the tq is insane on a 400+ motor, and the power curves are less of a peak, smoother...
I remember reading a few weeks ago a 408 w/ 241s (un ported) that went in the 460-70 range... Now, throw some heads on there and who knows what will happen.
460ish at 6200rpm or there abouts i believe, shows how much the heads are choking the motor.
a 408 with decent heads and cam should be a minimum of 500.
the tq is insane on a 400+ motor, and the power curves are less of a peak, smoother...
I remember reading a few weeks ago a 408 w/ 241s (un ported) that went in the 460-70 range... Now, throw some heads on there and who knows what will happen.
460ish at 6200rpm or there abouts i believe, shows how much the heads are choking the motor.
09-22-2005, 03:49 PM
#15
TECH Enthusiast
iTrader: (1)
Join Date: Oct 2004
Location: huntingtown ,MD
Posts: 738
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Ryan02SS
Mikey at Rapid Motorsports should be able to answer all your questions as he sends out pump gas 550+rwhp strokers. RapidMotorsports.com
09-23-2005, 12:33 AM
#18
Staging Lane
iTrader: (1)
Join Date: Jun 2004
Location: Pevely, MO
Posts: 72
Likes: 0
Received 0 Likes
on
0 Posts
for those of u that dont think u can make it out of 402 or 408 talk to this guy. its the real deal. https://ls1tech.com/forums/drag-racing-results/381685-can-you-say-9-second-n-ls1-6-speed.html
