• Welcome to For E Bodies Only !

    We are a community of Plymouth Cuda and Dodge Challenger owners. Join now! Its Free!

Starting my 408 Stroker build...

Jetsurgeon

New Member
Joined
Nov 21, 2021
Messages
1
Reaction score
1
Location
IL
Hi all, looking for any tips you may have as I begin my engine rebuild. 72 Challenger Top Banana Rallye 4 speed. California car, factory ordered without the vinyl top :)
The block was replaced at some point with a 77 vintage 360. The block tested good and has standard bores. Ted at Opel Engineering is prepping the block for me to put a 408 stroker kit into it with the help of the team at Hughes Engines. Since I'm restoring the car I figure I may as well go with fuel injection (Holley Sniper?). With Dave Hughes' help I decided on his high compression stroker kit. He says that with his "Super Prep" CNC porting and combustion chamber work he is going to do to the Edelbrock RPM aluminum heads I just sent him we should be at about 11:1 for compression ratio, and with a mild cam will probably be in the 525 HP range, which is just about where I want to be I think for a "Hot" street car (was wanting it to be close in feel to my 2016 Plum Crazy Scat Pack Shaker car). As mentioned previously I plan on putting the Holley Sniper EFI (or similar) on this car, and I actually have a Holley Strip Dominator manifold laying around and wondering if that will do, or should I get the Super Victor?? They "look" very similar?...Any thoughts on that or anything else would be appreciated!
 

Righty Tighty

Well-Known Member
Joined
Mar 4, 2021
Messages
132
Reaction score
59
Location
Sahuarita, AZ
Welcome to the forum! I'll be following along, been looking do build a 408 for some time now. We have some very knowledgable members here who will steer you in the right direction.
 

autoxcuda

Well-Known Member
Joined
Apr 16, 2016
Messages
57
Reaction score
10
Location
Los Angeles
choose the intake your engine builder suggests.

I’m interested in 11:1 compression with pump 91 octane gas.

But to get 525 hp, it’s got to have a pretty healthy cam and that will bleed some compression down.

Has Opel already built your same combo before with EFI ?
 

70chall440

Well-Known Member
Joined
Dec 11, 2010
Messages
1,065
Reaction score
765
Location
Western Washington
Personally I think that compression is going to be an issue due to the quality of fuel available. In other words, that CR might take some drivability away, but then again with the aluminum heads perhaps not. I usually try and stay around 10:1 or so for anything I intend to actually use. But, since you are working with professionals, they definitely know what they are doing so it should be good.
 

Chryco Psycho

Well-Known Member
Joined
Dec 28, 2008
Messages
3,159
Reaction score
1,091
Location
Panama
Welcome to the forum .
with EFI the intake is far less critical although multiport injection is far better than throttle body injection so with T body injection a wet intake the intake is still more critical .
 
Last edited:

sir_veza

Well-Known Member
Joined
Feb 10, 2021
Messages
141
Reaction score
66
Location
Brampton, Ontario Canada
Hi all, looking for any tips you may have as I begin my engine rebuild. 72 Challenger Top Banana Rallye 4 speed. California car, factory ordered without the vinyl top :)
The block was replaced at some point with a 77 vintage 360. The block tested good and has standard bores. Ted at Opel Engineering is prepping the block for me to put a 408 stroker kit into it with the help of the team at Hughes Engines. Since I'm restoring the car I figure I may as well go with fuel injection (Holley Sniper?). With Dave Hughes' help I decided on his high compression stroker kit. He says that with his "Super Prep" CNC porting and combustion chamber work he is going to do to the Edelbrock RPM aluminum heads I just sent him we should be at about 11:1 for compression ratio, and with a mild cam will probably be in the 525 HP range, which is just about where I want to be I think for a "Hot" street car (was wanting it to be close in feel to my 2016 Plum Crazy Scat Pack Shaker car). As mentioned previously I plan on putting the Holley Sniper EFI (or similar) on this car, and I actually have a Holley Strip Dominator manifold laying around and wondering if that will do, or should I get the Super Victor?? They "look" very similar?...Any thoughts on that or anything else would be appreciated!
Welcome from Ontario, Canada. My Challenger also has a 408 stroked motor, (9:5:1 compression with a slightly aggressive flat tappet cam), but with a Holley 750 4 barrel. 94 octane gas is available in Canada but has 10% ethanol. For the last few years I've been using Klotz (KL-628) Octane Boost @ 1 fluid oz per gallon on every tank. Not cheap but it pulls out the moisture from the fuel and helps the motor deliver on it's potential...
 

sir_veza

Well-Known Member
Joined
Feb 10, 2021
Messages
141
Reaction score
66
Location
Brampton, Ontario Canada
Welcome from Ontario, Canada. My Challenger also has a 408 stroked motor, (9:5:1 compression with a slightly aggressive flat tappet cam), but with a Holley 750 4 barrel. 94 octane gas is available in Canada but has 10% ethanol. For the last few years I've been using Klotz (KL-628) Octane Boost @ 1 fluid oz per gallon on every tank. Not cheap but it pulls out the moisture from the fuel and helps the motor deliver on it's potential...
Sorry meant to add I'm getting 425 HP & 504 lbs torque to the wheels.
 

SDChallenger

Member
Joined
Jul 4, 2014
Messages
9
Reaction score
3
Hi all, looking for any tips you may have as I begin my engine rebuild. 72 Challenger Top Banana Rallye 4 speed. California car, factory ordered without the vinyl top :)
The block was replaced at some point with a 77 vintage 360. The block tested good and has standard bores. Ted at Opel Engineering is prepping the block for me to put a 408 stroker kit into it with the help of the team at Hughes Engines. Since I'm restoring the car I figure I may as well go with fuel injection (Holley Sniper?). With Dave Hughes' help I decided on his high compression stroker kit. He says that with his "Super Prep" CNC porting and combustion chamber work he is going to do to the Edelbrock RPM aluminum heads I just sent him we should be at about 11:1 for compression ratio, and with a mild cam will probably be in the 525 HP range, which is just about where I want to be I think for a "Hot" street car (was wanting it to be close in feel to my 2016 Plum Crazy Scat Pack Shaker car). As mentioned previously I plan on putting the Holley Sniper EFI (or similar) on this car, and I actually have a Holley Strip Dominator manifold laying around and wondering if that will do, or should I get the Super Victor?? They "look" very similar?...Any thoughts on that or anything else would be appreciated!
Thought you might like some encouragement in your project. Numbers matching 72 Challenger Rallye 4-spd. Added stroker kit, 6-pack w hood, Edelbrock RPM heads, mild cam, Firm Feel steering rebuild, TTi headers, etc.. Gets where I am going pretty fast. Good luck.
 

Attachments

  • Challenger - Arrival in Colorado.jpg
    Challenger - Arrival in Colorado.jpg
    2.1 MB · Views: 5

autoxcuda

Well-Known Member
Joined
Apr 16, 2016
Messages
57
Reaction score
10
Location
Los Angeles
Sorry meant to add I'm getting 425 HP & 504 lbs torque to the wheels.

Still impressive.

What cam p/n are you running?

Have you tried running it on straight 91 octane ?

What was the estimate of HP/TQ at the motor without drivetrain losses?
 

sir_veza

Well-Known Member
Joined
Feb 10, 2021
Messages
141
Reaction score
66
Location
Brampton, Ontario Canada
The specs on the cam are
duration at .050", lift 239 intake & 246 exhaust
lift .484" intake & .484" exhaust
lobe separation is 108

Yes I've tried 91 octane with and without Klotz but there's a slight ping (and knock) especially without the octane boost

I haven't had the motor dyno'd outside the car
 

autoxcuda

Well-Known Member
Joined
Apr 16, 2016
Messages
57
Reaction score
10
Location
Los Angeles
The specs on the cam are
duration at .050", lift 239 intake & 246 exhaust
lift .484" intake & .484" exhaust
lobe separation is 108

Yes I've tried 91 octane with and without Klotz but there's a slight ping (and knock) especially without the octane boost

I haven't had the motor dyno'd outside the car

Some wheel dyno will give a customer a conversion of what they think the hp/to is at the motor.

Just wondered if they gave that number or factor to you.
 

sir_veza

Well-Known Member
Joined
Feb 10, 2021
Messages
141
Reaction score
66
Location
Brampton, Ontario Canada
Some wheel dyno will give a customer a conversion of what they think the hp/to is at the motor.

Just wondered if they gave that number or factor to you.
My results are SAE numbers - weather corrected...not seeing an STD number on the print out if that's what you are referring to...BTW HP & torque peaked at 5200
 
Top