Planning to get rid of the 5.9 in my ZJ and drop in a forged 408. Hoping for 475-525fwhp with a 250 shot of gas or more if I could get away with it safely? Daily rig, must be able to cruise on the highway for hours. Something to scare some TBSS's with and still be used as a Jeep.

From what I've been able to gather, coolant temps will be easier to control but oil temp will rise. Thinking filling right up to the water pump inlets is the way to go. With the tall deck heights we have and 4" stroke. I can get high quality 10w60 synthetic in 5gal buckets at wholesale so don't mind changing oil every 3-5k to keep it from getting too thin. Will add an oil cooler and temp gauge.

Haven't read of any sbm guys running block fillers. Seems much more popular with sbc/sbf. Wondering why that is? Just don't want to regret not doing it later down the road, thanks.

 

Daily driver and block filler........buy a better block, I'm not sure whats out there for small blocks but I wouldn't fill a daily driver block.

 

https://www.racingjunk.com/8-Cylinde...&from=category

 

Sounds like it wouldn't work but folks are running their daily's with a tall fill just fine other than adding an oil cooler. Mostly what I'm picking up on the LS forums.

Thanks for the link, did he mean 9.6 deck instead of 9.2? Not familiar with the older stuff but I already have magnum indy heads and want to stay FI. Not sure but thought I couldn't use the older blocks?

 

Sounds like fun. But it will be short lived as a street daily driver. Plenty of the guy I know running half filled block have cooling issues.
The folks that I know that do this type of Mod, only do a 1/4 fill and run a short skirt piston, However those are still not daily drivers
I would think the main caps would be huge issue on a stock block even being 1/2 filled.

Keep us posted on what you try and the results...

 

Oh man, sounds like I should skip the block fill and nitrous. Figured the fill would help the bottom end last longer with the longer stroke.

Stuff I have laying around: IMM indy magnum heads, 58mmx2 FB TB, 4bbl m1, 1.7 rr, 24lb injectors, 180 tstat, cloyes timing set and tensioner. Have a new 212 110lsa .332" single pattern cam I was going to use with the 5.9 but I think the 5.9 is due for an overhaul. Rather go 408 with either a 230 115lsa single pattern or 230/236 115lsa. Expecting close to 500hp/tq.

Since I won't be going over 550hp/6500rpm max, should I even go with forged crank and pistons for about $700 more? All scat components so thinking I should be fine with their cast stuff.

 

Dude... 550hp on cast stuff.. Wow.... I think you better call Brian and have a chat with him on what your trying to do with your left over stuff.
I see this having a short fuse building it this way.... You know, one of them "Sayonara Motors"
Brian might be in with the block fill, but I don't think he will think it is a good idea also.

Bottom line, it's your money. But a daily drive built like this.... I don't see it happing.... Sorry..

Keep us posted on what you decide....

 

I broke a stock cast crank with 350 HP /360

 

I'll stick to forged and NA lol thanks for the advice guys. Saving me trouble down the road. Saw a dyno chart of a 408 magnum with mildly ported heads, port matched m1 and similar mods with a single pattern 236 cam hit 550hp and almost 550tq. Carried peak power up to 6300rpm so figure I'll be in the sweet spot with a 230 single pattern or 230/236. Shifting at 6k and limiter at 6300.

One thing I haven't gotten anywere with is what my exhaust duration should be with a wider LSA like 115. Don't know if a wider LSA wants less exh duration or more. Midrange is very important to me since I have some tall *** gearing. 1st goes to 60mph and 2nd to 100mph at 6k rpm. Stuck using doug thorley tri y headers with 1 5/8 primarys to a single 3" mandrel exhaust. Going duals is not an option unfortunately.

 

Taken from forAbodiesonly, bongy337

Mopar 408 Magnum
Engine Specs

408 Cubic inches
Bore 4.030
Stroke 4.00 Ohio Crankshaft 4340
Rods Cat 6.123 H-beam
Pistons Probe
Compression 11.5
Cam Comp XFI Lobe HYD roller (236/236 duration at 0.050-inch, 0..576/0.576-inch lift). Heads Edelbrock RPM Magnums Ported
Intake Mopar M1 single plane Ported
Comp 1.6 ratio exhaust roller rockers
Carb 1050 Quick Fuel
DYNO RESULTS Mopar 408 Magnum Stroker SuperFlow 901 Engine Dyno
STP Correction Factor Tested

RPM TORQUE HORSEPOWER
3200 491 299
3400 495 321
3600 496 340
3800 508 368
4000 509 388
4200 517 414
4400 522 438
4600 529 463
4800 532 486
4900 533 497
5000 532 506
5200 528 523
5400 522 537
5600 513 547
5800 501 553
6000 484 553
6100 477 554
6200 468 552

 

How did this motor work out as a daily drive?

 

Not sure about that build specifically but on some FB groups folks with similar builds are happy with them in rams, jeeps and dakotas. I don't see why a build like that would be an issue as a DD though? Reasonable street cam, high quality parts, safe rpm, etc.

 

That motor is going to like gear and converter.