402 & 408 guys?
Thread Starter
Instructor
Joined: May 2006
Posts: 150
Likes: 0
From: Jacksonville North Carolina
402 & 408 guys?
So how many of you guys have gone with a 402cid or a 408cid set up? If you did, what kind of set up (as in heads, cam), and how much power are you putting down.
I'm thinking about one of these set ups but i'm not sure exactly what i want. I use my car as a daily driver and want it easy to drive.
Also i know this is a retarded question but how are your mpg's with these big motors?
I'm thinking about one of these set ups but i'm not sure exactly what i want. I use my car as a daily driver and want it easy to drive.
Also i know this is a retarded question but how are your mpg's with these big motors?
Advanced
Joined: Apr 2005
Posts: 65
Likes: 0
402
All forged parts
Lunati crank
Callies rods
Eagle pistons -3 cc
ARP main, rod, and head bolts
68 cc 225 AFR heads (ported and polished AGAIN)
Comp 921 springs
Comp 7.400 pushtubes
42 lb injectors
Fast 90/90 port matched to heads and TB
ASP underdrive pulley
Cometic .040 gaskets
11.6 CR
LS2 conversion parts
Motion dual LS2 gear and chain set
Melling Ported oil pump
Stock roller rockers
Comp R lifters
Comp cam 251/255 661/664 111 sep
Cobra T-1 intake
LG headers
Random cats
X-pipe
Borla 4 tips
Aussie clutch and flywheel
Hurst shifter
All forged parts
Lunati crank
Callies rods
Eagle pistons -3 cc
ARP main, rod, and head bolts
68 cc 225 AFR heads (ported and polished AGAIN)
Comp 921 springs
Comp 7.400 pushtubes
42 lb injectors
Fast 90/90 port matched to heads and TB
ASP underdrive pulley
Cometic .040 gaskets
11.6 CR
LS2 conversion parts
Motion dual LS2 gear and chain set
Melling Ported oil pump
Stock roller rockers
Comp R lifters
Comp cam 251/255 661/664 111 sep
Cobra T-1 intake
LG headers
Random cats
X-pipe
Borla 4 tips
Aussie clutch and flywheel
Hurst shifter
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
403 here. Same as 408 with thicker walls. Mileage should be a few percent less. I went with the iron because of the inherent bore distortion that occurs with sleeved blocks as well as the lower expense to bore and freshen up later. Will be making ~900hp and expect to have to freshen up in a few years.
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
Specs in sig. Just did mileage on 90 mile trip. Reset when on highway. Averaged 25.8 @65-70mph, stopped for tolls etc. Get less around town. ~15-18mpg. Not a retarded question at all, especially with todays gas prices and it being a DD. As far as drivability... it's all in the tune.
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
My factory stock car came from the factory with an LS2 403 built with L92/LS3 heads.
510/470 (this week
) and drives fairly close to stock. I drive mine in DC rush hour and take it on long trips all the time. I average about 15 MPG driving it any way I want to.
510/470 (this week
) and drives fairly close to stock. I drive mine in DC rush hour and take it on long trips all the time. I average about 15 MPG driving it any way I want to.
Last edited by WKMCD; Jul 9, 2008 at 11:54 AM.
Advanced
Joined: Apr 2005
Posts: 65
Likes: 0
After tuning the ECM, the fuel mileage shown in the display will be incorrect. The injector offset has been changed. Don't think the ECM is looking at fuel flow. It is a reading that the ECM is giving you off a known injector flow using the factory setting. Once you change that offset, IT IS INCORRECT. If in doubt, figure it out on paper and then look at the display, you will see it isn't correct anymore after a MAJOR tune. No frigging way my 402 at 549 rwhp is getting 32 mpg on the highway. That is better than a new Honda Civic.
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
After tuning the ECM, the fuel mileage shown in the display will be incorrect. The injector offset has been changed. Don't think the ECM is looking at fuel flow. It is a reading that the ECM is giving you off a known injector flow using the factory setting. Once you change that offset, IT IS INCORRECT. If in doubt, figure it out on paper and then look at the display, you will see it isn't correct anymore after a MAJOR tune. No frigging way my 402 at 549 rwhp is getting 32 mpg on the highway. That is better than a new Honda Civic.
BTW, one big factor that is helping your gas mileage is higher than stock compression ratio. That will increase the efficiency of the engie quite a bit. Also, a new Honda Civic weighs more than your car ans is less aerodynamic.
Melting Slicks
Joined: Aug 2005
Posts: 2,873
Likes: 614
My uncle had a 404ci LS2 built by MTI Racing for his C5Z over two years ago. It's making 480/470 with some ported LS6s and a decent cam. It's been pretty much bulletproof over the past 10K+ miles including trackdays and hard driving. Still gets 26-27mpg on the highway with 3.73s.
The low-end torque is the best part of stroker motors. You might see a stock cube motor make the same high-end power but the low and mid-range is far superior with a 402/408. Most vendors on this site have experience with these engines and will make great power. It's worth the money.
The low-end torque is the best part of stroker motors. You might see a stock cube motor make the same high-end power but the low and mid-range is far superior with a 402/408. Most vendors on this site have experience with these engines and will make great power. It's worth the money.
Last edited by Kappa; Jul 9, 2008 at 06:41 PM.
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Burning Brakes
Joined: Feb 2007
Posts: 1,037
Likes: 0
From: Kansas City Missouri
St. Jude Donor '09
I have a 408 sleeper setup. It has:
Eagle Crank
Eagle Rods
ETP 215 62cc heads
Diamond -2cc pistons
11.5:1 CR
LPE GT11 Cam
Stock Rockers
Stock Lifters
LS6 intake
SLP Underdrive Pulley
1 3/4 headers
Stock Paper Air Filter
Made 445hp/465tq on a very safe tune and gets about 20mpg still. I drive it everyday and it is quiter than any other c5 out here.
Eagle Crank
Eagle Rods
ETP 215 62cc heads
Diamond -2cc pistons
11.5:1 CR
LPE GT11 Cam
Stock Rockers
Stock Lifters
LS6 intake
SLP Underdrive Pulley
1 3/4 headers
Stock Paper Air Filter
Made 445hp/465tq on a very safe tune and gets about 20mpg still. I drive it everyday and it is quiter than any other c5 out here.
Le Mans Master
Joined: Nov 2003
Posts: 8,004
Likes: 250
From: Tampa Fl
St. Jude Donor '12-'13-'14
Someone's nose is growing ! 