I am going to be rebuilding my motor....right now i have all bolt ons for the motor and am looking to modify the motor itself. The truck itself is sitting with a 6" lift and 35 inch tires. I know I will be doing a cam. I really dont want to mess with the computer. I dont want to mess with the compression either so that way the computer can run itself. I want to know what any suggestion were made. I am looking for make serious horsepower. So let me know thanks!

 

I am a little lost here. You want to make serious HP by changing only the cam? If you want to make HP, you will have to bore, stroke, and work the heads in addition to the cam.

The reason I say this is because I am in the middle of a build currently. We started with a HO305, moved up to a HO350, and are now building a HO383. Once you begin building the motor, the internals for a stroker are no more expensive than normal parts. Realism is important here, a cam may give you a few HP, but even so, the computer being modified can be a good way to release HP, and if the right person tunes the computer (www.wait4meperformance.com); it can be inexpensive ($150 includes a new computer). Jesse has programmed 2 computers for me and is writing the program currently for the 383 stroker.

Without knowing the year of your truck, I have learned on this board that the Vortec 350's (97-99) are only good up 5800 RPM and 400 Crank HP (this is due to the manifold) I am not personally sure about these numbers, however they are backed up well here.

Mike

 

I know the rev limiter is true as far as I know, but you can get around both, you can get a marine intake or a ramjet and for the pcm you can swap in the 411pcm and you will get rid of the rev limiter. It all depends on how much $$$ you want to spend.

 

money money money

How fast do you want to spend?
i did my Marine Intake swap for $975 including PCM tuning.
Here is the marine intake swap page
http://www.pacificp.com/forum/viewtopic.php?t=317

Here is the 411 PCM conversion info including 96-97 PCM pinouts and 98-2000 PCm pinouts and the 2002 L31 Vortec 350 Chevy Van 411 PCM pinouts
http://www.pacificp.com/forum/viewtopic.php?t=3240

Slowly but sureley the L31 is being cracked.

here is another shot of a Marine intake manifold as it supplied by GM before MERC sprays them RED.
http://www.sfatek.com/images/efi.jpg

peace
Hog

 

Hey guys
If we can't rev these dam chevy trucks with the vortec 350s past 5800 lets make lets play harder than the other guys by using high compression 383s with 1 3/4 inch long tube headers, good aftermarket cylinder heads, cams with decent duration and about 575" lift, and fuel/air managment like this intake manifold from Edelbrock for vortec heads.

 

If your willing to spend the money to eliminate the 2 things that make our L31 truck so hard to mod then you could make a beast out of it. The new injection system and the new comouter will be pretty expensive mods, but once you get past that its just like any other SBC 350, it can be made very powerful. The computer can be tuned to run well with any internal mods that are done too. You will need a computer tune to make the nest of any big mod you make (like a cam). It would be stupid of you not to tune for it.

-Rob Nap

 

actually the pcm is not very costly to do you can find a 411 pcm for around 100 and all you have to do is wire it in and get it flashed with a van file on it. But as far as the intake goes I am still trying to find a cheaper way totake care of that.

 

If you find a cheaper way, let me know!!!!

 

The 411 PCM or a Roadrunner PCM emulator is the way to go on the Vortec 305/350/454.

peace
Hog

 

Has anyone got a total price for both the marine intake and the ramjet intake to see which is cheaper?