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mboger 06-15-2005 08:21 PM

5000 on 7.4
 
has anyone run a 7.4 at 5000 rpms and it held up decent

Hydrocruiser 06-15-2005 08:53 PM

Re: 5000 on 7.4
 

Originally Posted by mboger
has anyone run a 7.4 at 5000 rpms and it held up decent

I was told it does not have 4 bolt mains...and to keep it to 4800 RPM...but what's 200 RPM anyways right? :D

HOTTZU98 06-15-2005 11:50 PM

Re: 5000 on 7.4
 
200 more rpm could lead to a bucket full of piston fragments.

tomas_wallin 06-16-2005 03:04 AM

Re: 5000 on 7.4
 
According to the feedback i have got it should not be any problem. I am going to rev my own rebuilt 7,4 Gen V (1995) to 5100rpm...

tpenfield 06-16-2005 09:41 AM

Re: 5000 on 7.4
 
Rev as high as you want, it is your engine.

Keep in mind that at that RPM range you are on the down side of the horsepower curve and that those extra revs generally come at the expense of torque.

Airpacker 06-16-2005 06:03 PM

Re: 5000 on 7.4
 
I ran my old 330 ( 7.4) to 5200 for 360 hrs intermittently after a cam and intake change before I rebuilt it. It has 4 bolt mains but it also has a cast crank and pistons and small rod bolts.

tomas_wallin 06-16-2005 07:25 PM

Re: 5000 on 7.4
 

Rev as high as you want, it is your engine.

Keep in mind that at that RPM range you are on the down side of the horsepower curve and that those extra revs generally come at the expense of torque.decent
I assume that mboger is going to change something in the engine - cam etc. Otherwise - with a std 7,4 it won't do much of anything besides making the engine much more unreliable...

The cam I put in my 454 has rpm range 1600-5800 and I will set the rpm limit to 5100 to make the engine last.

mboger 06-16-2005 09:20 PM

Re: 5000 on 7.4
 
Im running the 7.4 with a stage one procharger on it now with a 28 labbed bravo prop and running 71 on gps at 4700 rpms and thinking about changing the pulley on blower to raise the boost from 5lbs to 7lbs and would like to put the rev limiter up to 5000

tomas_wallin 06-17-2005 04:51 AM

Re: 5000 on 7.4
 

Originally Posted by mboger
Im running the 7.4 with a stage one procharger on it now with a 28 labbed bravo prop and running 71 on gps at 4700 rpms and thinking about changing the pulley on blower to raise the boost from 5lbs to 7lbs and would like to put the rev limiter up to 5000

Do you have cast or forged rods and pistons? If you have cast ones I read somewhere that 5psi boost is the maximum it will take.

mboger 06-17-2005 10:47 PM

Re: 5000 on 7.4
 
I have cast so will probably leave it alone this year and put bigger power in it during the winter thanks everyone for all the info


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