Allright-I know I'm asking about some ancient technology here-but if anyone has any info, I would appreciate it. I want to know if anyone has or knows of any modifications that would be advisable for this engine-in regards to head milling/porting/valve jobs. Or TB boring and possible cam swapping? Any info would be great-thx

 

A local guy built a 98 5.7 to put in his jeep about a year ago. I'm not 100% positive about this but If I remember right he took a 98 5.7L, had some minor head work done (shaved the heads and cleaned up ports) then put a cam from an LT1 Trans Am and made a lil over 350hp at the crank. I'll try to give him a call shortly and find out exactly what he did and all the specifics.

 

Excellent-sounds great, thx

 

sell the 98 and buy a 99+

sorry prolly shouldnt of said that..haha i had 97 gmc (that i totaled) that had a hypercrap and dual straight pipe is was ok for what it was but for the 99 and up have so many more performance parts for them and you have alot wider tuning range for the 99+ trucks..for what you can spend on those you could prolly spend that money on a 99 and and up and have 12-13 second truck but i know some one will prolly prove me wrong

 

I have seen some people switching out the spider injection for Ram Jet Injection. If you went this route you could Ram Jet Computer with FAST XFI unit and your performance capabilities would be endless. However both of these computer are stand alone so they will need a stand alone tranny computer.

 

Another thread with NO LOVE for the Gen-I Vortec! Come on guys....

I'll share the truth. They have a ton of potential, but at a price. The stock L31 Vortec (350) shortblock will handle 550HP day in, day out, without burning a drop of oil, slapping a piston against a cylinder wall, going lean on cylinder 7, or busting piston ring lands. (that's a DIGGER y'all, lol)

Making power with one is more complicated:
1. The stock cam was designed in an era where trucks were built to pull things. It's profiled for TORQUE, not RPM.
2. The valve springs on the stock heads only handle about 4800RPM, beyond which the springs are not strong enough to control valvetrain geometry.
3. Stock heads support only low lift, something like .450" due to the design of the valve guides.
4. Stock head gaskets support 425HP only. Keep this in mind if you like laughing gas.
5. Stock intake manifold houses stock fuel injectors. These are non-upgradable 19 lbs/hr proprietary injectors housed ina special spider assembly. To get bigger injectors in there the intake must be swapped out to something else. There are several choices for that.
6. The stock computer can only be reprogrammed by one product on the market. It was developed by TunerCAT and was recently (unfortunately) sold to Jet electronics who immediately restricted the number of vehicles you can flash and added $100 and change to the price tag.

Depends how much you want to spend but a Vortec 350 is no slouch if it's limitations are overcome. The stock computer can even run the show for you.

 

In regards to JAMES B-thanks for the info-I was aware of some of the valvetrain limitations-I know that people want the speed thing-but I am actually looking for the more Torque factor here-I actually use this truck to move cars and such, long distances. Anything that can give me a bit more grunt to it is beneficial-I was contemplating contacting Jesse at wait4me to see what options I may have thru that.

 

There is a basic start to upgrading any truck no matter year. It usually follows headers, exhaust(in your case, upgrading the 2" and smaller pipe to 2 1/2" from the headers out), computer tuning and taking off the little torque management that GM put in those engines, and air intakes. Stay away from the throttle body spacers b/c they will give you nothing for performance. Other mods would be electric fans and roller rockers if you wanted a little more lift and less friction. However, some vortec heads have to be modified to be fitted with a 1.6 rocker so be aware of that. Good luck!!

 

all vortec heads have to be modified for 1.6 RRs, but it is simple you just have to drill the pushrod holes out one size bigger, from 3/8 to 1/2.....as long as you get self-aligning RRs...if you don't you have to put guide plates in