A I located my old dyno run sheets:
The best my '87 car would pull with the 350 stock bottom end, ported factory plenum, high flow runners, AFR heads, FMS 24#/hr injectors, AFPR @ 46psi, cam, etc, etc, was 242 RWHp.


Something is wrong here.

 

I agree

 

Be patient,

It took me months to get my vortec car to run right- everything has to be healthy. If you had some sort of problem to begin with it will only be magnified. 6* of timming is fine, don't mess with the base timming, everything else needs to be done in the PROM.

My car ran soooo much stronger once it was tuned, it's not even funny.

Just make sure no air leaks, valves adjusted, fuel system is ok, etc.. sensors are ok ..

Vortec's are great once you get them sorted out, I have no regrets. but it was a PITA to get it right for sure.

 

Drop the timing to 0* and see what happens. Vortecs and Swirl Ports need NO MORE THAN 32* TOTAL ADVANCE @ 2,600 and full load. It can run around 42-45 at part throttle and still be fine.

What does the fuel pressure do under load?

BTW, Speedtek (In Fort Worth) is about 5 miles from my house, Hurst.

 

i am going to keep it at 6 for now and when i get it tuned i am sure i will play with it.

355

i am in saginaw,

 

LOL at the plugs, that could definitely do it. Without the LT1/Vortec style long reach plugs your spark would just about have to be going off well down into the plug hole, not in the combustion chamber. If that didn't wreak havoc on the flame front and such and combustion in general and suck some fairly serious power out I don't know what would...

It will be very interesting to see what kinda numbers it puts down now, perhaps the plugs didn't hurt as much as one would think though (I'm betting on some serious rwhp gains myself...)

 

Dont expect a WHOLE lot more, keep in mind he is using the stock cam.

The cam that comes in Vortec 350 chevy truck motors is bigger than the L-98 cam.

 

The Vortec Cam is the B-Body LT1 cam. It really only has a tighter lobe seperation angle than the L-98.

 

LSA = 111.5 deg

lifts at the valve with 1.5 rocker ratio:
0.414 or 0.418" intake depending on year
0.428 or 0.430" exh depending on year

duration: 191.5 deg intake, 196 deg exh both @ 0.050" valve lift

Used in 1994-1996 Bcar L99 and LT1; 1996+ Vortec trucks (L31 5.7; probably also L30 5.0.

The F/Y car LT1 cams have more lift (around 0.45"), more duration (202/207 deg i/e) and a wider LSA (115 or 117 deg). L98 cam (specs near the bottom of this page here) is similar to the F/Y LT1 cam.

 

There is some excellent information here!! This board rocks!

I can see now, with all my planned mods, I need to learn how to tune!!

 

the stock 1989 L-98 cam is bigger than that ... 207/213 duration with a fat 117 LSA



The guy who has only 242 rwhp with AFR heads ...MANNNNN something wrong there