to post this but whatever. i am new to the dodge world. i am building a off road rock racing car. and since i have not seen a late modle 5.7 hemi in a rock racer i thought it would be a good idea to build a car with one in it. so i have a couple of questions,

1. how much power can i get out of a 07 5.7 hemi without the smog stuff? (this race car will be for offroad use only)
2. will the motor be ok to run in the 4500 rpm to the 5000 rpm all day?
3. what would be the best trans to put behinde the motor?
thats all for now. and just remeber i know these are stupid question but i did just leave the toyota world and step up to dodge world. thanks for any info

 

yup, this would be the correct place for you to post! Welcome to the foum by the way, although I cannot help you out too much, I'll let other more educated forum members in this area chime in and give you some insight.

EDIT: I believe the answer to your first question would be about 310hp, the newer (2009) hemis are 390 I'm pretty sure, correct me if I'm wrong.

 

The stock 2007 HEMI made 345hp and 390ft/lbs tq. With a free intake, headers, a free flowing exhaust as well as a custometune (to delete MDS and get the most out of running a higher grade fuel) I would estimate a nice 400hp and 450ft/lbs.


Oh totally forgot throw a cam in there too for another 30 or so hp. and yes I am sure that if it is cooled right 5k should be fine just done go over the factory 5600 and you should be perfectly safe.

 

thanks for the info. but how would a stock trans hold up?

 

If your not running a crazy amount of upgraded on the motor and the power is still around stock it should hold up fine but if you start adding things like turbo or supercharger you might need to make tranny plans. I could be wrong but I'm sure someone will say something if I am.

 

I plan on getting as much reliable horsepwer as i can out of the motor. i dont want to be stranded out in the desert. I just read that you could mate up a 4L65E (gm trans) to the 5.7. is this true?

 

I have seen kits in hot rodding magazines that allow the gm tans to mate to the HEMI. The brand slips my mind but I know it can be done.