408 stroker

-
Never dynoed my 408 but did experiment with shift rpms. I tried everything from 6000 to 7000 rpms, anything below 6400 or above 6600 it would slow down so i shifted it at 6400.
 
Depends on what your cam specs are, if you put in a smallish cam, your peak HP and TQ will be significantly lower than if you run a very large cam. For example, [email protected] .510 will produce a peak in the area of 5000-5800 rpm while a [email protected] .575 lift would produce peak closer to 6200-6600. The first example I would shift around 5000-5200 and the second 6200-6500.
There are other factors as well, cylinder heads and intake, rotating mass weight etc, but for the most part, a well build engine with the correct collection of parts that compliment each other will produce consistent results.


If you get posters to list cam specs and shift points, you will find this info to be pretty predictable.
 
I'm running a small cam in my 408 and it is great for making power down low and it redlines at 5600
I probably put out more torque at idle then most tuners at redline
 
manually shift between 6500-7000, as its still pulling either way. If I just leave it in Drive, it shifts at 6000, for playing on the streets, or I just don't want to manually shift it.

On Brian's dyno, it was still making power up to 7400, but don't feel I need to rev it that much more.
 
diymirage said:
I'm running a small cam in my 408 and it is great for making power down low and it redlines at 5600
I probably put out more torque at idle then most tuners at redline
Click to expand...

found my sheet
peak torque is 470 ft-lbs at 4000 RPM
peak power is 423 hp at 5400 RPM
 
Over 7000...rpm for me too..419 still trying to explode it..let u know soon.but I don't think so.:finga:motor is just getting stronger...2500 miles..TNT still
 
As someOne mentioned (cough cough - MagnumMopar)
Cam specs please
Gear ratio and tire size would help as well.
 
diymirage said:
found my sheet
peak torque is 470 ft-lbs at 4000 RPM
peak power is 423 hp at 5400 RPM
Click to expand...
Whoa! That torque has got to be some nice street engine. Bet you could run just about any rear with that.Ima thinkin 3.23s with a 2.45low. That would put you at about 65 mph for the 1-2shift. Yummy! I like it!
 
I do run 3.23s in there, with an N-50 tire
she has no problem getting off the line (as long as you kinda creep into to throttle, otherwise she'll just sit there and roast the hides)

I'm not sure where my 1-2 shift point lays, but unless I'm on the highway...it is probably close to speeding territory
;)
 
laj340 said:
Over 7000...rpm for me too..419 still trying to explode it..let u know soon.but I don't think so.:finga:motor is just getting stronger...2500 miles..TNT still
Click to expand...
I had a 340 before we built this 360 , wish ihad never got rid of that engine . It was a 69 340 +.030 that would buzz 72 all day long , and like you said it just got stronger . I pounded that motor 25 years without changing anything but oil , plugs and carb . I haven't had this 360 3 years and popped it 2times now with these hyperutectic cast pistons that are supposed to be so nice. talking right now about what is an affordable forged piston and rings for under 600.00 LUV 340"s .
 
mopowers said:
What heads are you running? Any work done to them?
Click to expand...
Stock 75 heads, I think they are J castings
Mike installed the larger valves in them and I'm sure he massaged them some aswell, but you would have to check with him for details on that
 
diymirage said:
found my sheet
peak torque is 470 ft-lbs at 4000 RPM
peak power is 423 hp at 5400 RPM
Click to expand...

diymirage said:
Stock 75 heads, I think they are J castings
Mike installed the larger valves in them and I'm sure he massaged them some aswell, but you would have to check with him for details on that
Click to expand...

diymirage said:
comp cams XE268H
COMP Cams: Xtreme Energy™, XE268H <br> Great for Street Machines
Click to expand...

Can I ask what Dyno this was tested on? Not that I doubt you but the #'s sound high to me. Was there anything else done? what intake? comp? Maybe I am just missing something. sorry no trying to be rude. Have been gathering parts for 408 for a bit now,open intake bowls & gasket matched EQ's, [email protected] .560" roller, modified mopar EFI, big injectors and 1000 cfm TB and my stuff pencils out at 470 HP 475 TQ, I would think there would be a bigger difference or are my numbers low? I cant find any dyno sheets from FI 408 except for chassis dyno w Dakotas. I have built a few of these but never got any dyno time as it was in Portland or Sacramento. They are stupid fast though, guess I need to buy some dyno time now Medford has one:)
 
magnummopar said:
Can I ask what Dyno this was tested on? Not that I doubt you but the #'s sound high to me. Was there anything else done? what intake? comp? Maybe I am just missing something. sorry no trying to be rude. Have been gathering parts for 408 for a bit now,open intake bowls & gasket matched EQ's, [email protected] .560" roller, modified mopar EFI, big injectors and 1000 cfm TB and my stuff pencils out at 470 HP 475 TQ, I would think there would be a bigger difference or are my numbers low? I cant find any dyno sheets from FI 408 except for chassis dyno w Dakotas. I have built a few of these but never got any dyno time as it was in Portland or Sacramento. They are stupid fast though, guess I need to buy some dyno time now Medford has one:)
Click to expand...
the comp cams k20 227 is a nice 1 need 1.6 rockers tho
545 or 557 lift and like 245/237 @ 50 1050 carb on anairgap tsi built trans 10 second car now juice it HAGR81 GUYS
 
You must log in or register to reply here.
-

Back
Top