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cam advice on a 98 k1500 5.7 vortec build

  
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cam advice on a 98 k1500 5.7 vortec build

 
danomatic danomatic
New User | Posts: 4 | Joined: 05/09
Posted: 05/01/09
07:51 AM

I am having my old 5.7 rebuilt bottom end balanced and blue printed. It will be bored .30 over, stock piston replacement I think about 9.5 to 1 CR. New heaver casting 906 vortec heads ported and polished with the bowels blended and a three angle valve job. I am also having a cloyes roller timing chain installed. I am also updating the fuel injection system from the scfi to the mpfi, new accel dizzy and coil, stock exaust manifolds at this time, I have duel cats and a two in two out cat back exaust system. Transmission is a 4L60e with beefed up torque converter. I also Have a completly rebuilt rear end with 3.73 gears. I have three cams that have been recomended to me. All comp cams with 1.5 roller tip rockers.
1)08-300-8 262hr-12
 Int. .450 Lift with a 206 duration
 Exe. .480             210           112 degree LSA
2)08-525-8 tpx246hr-16
 Int. .470             194
 Exe. .464             206           116 LSA
3)08-500-8 xr258hr
 Int. .480             206
 Exe. .488             212           112 LSA
Any help would be appreciated thanks Dano.
I am looking for good torque through out rpm range as well as HP with decent fuel economy. This will be a daily driver trying to do it right and get the most bang for the buck.  

blacksheep84 blacksheep84
Enthusiast | Posts: 350 | Joined: 02/09
Posted: 05/01/09
01:52 PM

u can go bigger on the cam especially because you have a torque converter , any idea how much it will stall?  

GibTG GibTG
Guru | Posts: 1985 | Joined: 10/03
Posted: 05/01/09
02:43 PM

For a daily driver where fuel economy is of concern porting the heads was pretty much unnecessary. The vast majority of the time porting will attempt to raise the power band. This is especially true if you have someone doing it that doesn't know what they're doing and they end up removing excess material. The only gains for porting to a daily driver would be a bowl blend left with a relatively rough finish and slightly more focus on the exhaust. Even a gasket matching on the intake would most likely be unnecessary.

Bowels relaxed? That's a new one!

What exactly is scfi?

I would stay away from a 116 LSA, that's a little unnecessary and will cost you plenty of midrange power. I think that your third choice would be best. Even this option should still make plenty of vacuum.  
~Gibs

danomatic danomatic
New User | Posts: 4 | Joined: 05/09
Posted: 05/01/09
03:27 PM

The torque converter is a stock stall with beefed up insides. The bowels were blended not relaxed sorry. SCFI sequential central fuel injection. I think they did a gasket matching on the heads.  

GibTG GibTG
Guru | Posts: 1985 | Joined: 10/03
Posted: 05/01/09
03:38 PM

Why is it that you're replacing sequential fire with a multi-point fuel injection system? Isn't the sequential system more advanced?  
~Gibs

danomatic danomatic
New User | Posts: 4 | Joined: 05/09
Posted: 05/02/09
07:04 AM

No the multiport fuel injection is a direct replacement for the scfi which had problems with the poppets clogging or getting stuck open/closed because of fuel additives the mpfi puts the injector right at the port and eliminates the poppet. The scfi system was replaced in 2000 because of this problem. with 11 years and 176000 miles on the old system I felt it was time for an update. I also have noticed some of the symtoms associated with poppets sticking.  

SMOKESHOW SMOKESHOW
Guru | Posts: 1001 | Joined: 09/08
Posted: 05/02/09
07:49 AM

with all the work you are doing, why not spring for some headers?  

danomatic danomatic
New User | Posts: 4 | Joined: 05/09
Posted: 05/02/09
01:12 PM

I have pretty much shot my wad at this point. I will have to wait until I have saved up a little more cash. I have heard that a wider lsa on a cam with mostly stock components will actualy make more power. ??? What type of headers do you recommend. The engine builder that I am working with is wanting to lean toward the cam with the 116 lsa he says it will work with the computer better help to not through any codes, and give me good power through out the intended rpm range 800-5000. Any thoughts??? thanks for the help guys.  

SMOKESHOW SMOKESHOW
Guru | Posts: 1001 | Joined: 09/08
Posted: 05/02/09
02:37 PM

I would lean towards XR 258 or maybe the 262HR12.