Ok just for the record, all you guys running with vortec heads, did you take the egr function out of the ecm or just run with out it? I'd like to know what your experences have been as far as spark knock, fuel milage ect... I want to put these heads that are redrilled from pace parts ($484) on a stock '95 L05. My cam at .050 is 195/202. Compression is 9 to 1 with 64cc heads, if a stock truck L05 is the same as the truck replacement crate motor. Would these heads work well with the stock L05? I'm looking for a torque monster but still be able to pull 5000RPM. I am mostly concerned with the egr issue cause I can change the cam and intake later when more funds are avalable. Anything you can add would help a bunch, thanks!!!

 

My experience is on a stock '91 LO5. The engine pinged and rattled with the EGR valve disconnected. The ECM I have adds some 6+ degrees of timing and cuts fuel during EGR operation.

When I disabled EGR in the EPROM, the engine ran fine (EGR still unplugged).

The proper way to do it IMHO is to disable the EGR in the EPROM. Other wise you are risking detonation during cruise and light throttle driving which is hard on rings, rod bearing, etc.

You can test it yourself by unplugging your EGR valve.

 

Do you realize that your intake won't match the heads. The intake ports on the manifold will not cover the intake ports on the head. You not only have a sealing problem you will have a very mismatched port configuration. If you want to use the Vortec heads, why not buy a package deal that comes with everything. It will have a manifold, intake gaskets, heads and bolts. I think the package sales for around 650.00 to 680.00. Check with Pace Parts, I think thats where I saw an ad for the complete kit.

Who can turn the egr off in the chip that won't charge as much as it would cost to buy a custom chip.

Steve

[This message has been edited by steve8586iroc (edited March 23, 2001).]

 

If i wanted to slap some vortec heads on my 91 chevy p/u/350, would it fit right or do i need some mods?

86 Iroc,305 tpi
91 chev p/u/350/3.73 gears/ram-air

 

well you need the proper manifold, vortecs require a vortec specific manifold like edelbrock makes the performer vortec which would be fine for a combo like that. I rode and raced a convertable 88 camaro with that setup and it flat out flew although i think there might have been some headwork

 

Thats it, just the intake? what about valve covers?

 

You would need to either buy the new GM TBI/vortec intake (recast Edelbrock TBI intake), or better-get the Holley 1741 plate and mount it to a carb intake. You also have to address the fact that the vortecs have no EGR passages. I think the GM intake has a set up with it to take exhaust from the manifold/header. Otherwise, you basically need a chip to turn off the EGR so it doesn't look for a signal. You will also need an adjustable fuel pressure regulator, because this will probably make you lean due to the increased efficiency of the heads. You will also need different spark plugs for the vortecs-they are longer (3/4" thread). I use Bosch HR8DPX.

------------------
'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust

 

I thought because Pace Parts redrilled vortec heads for the standard bolt pattern, that you could use an old style intake with them. Am I wrong?!? Does anyone else with vortec heads have anything to add about running without egr with normal ecm control? I would really like to try these heads on my L05 but if the ecm and egr will cause a big problem,I might have to look for an alternative. I'm thinking vortec heads and headers will really wake up a stock L05, right?!?! Thanks

 

They will but you will have to do a lot of tuning with fuel pressure, injector sizing and ignition timing. As for the manifold I believe a vortec performer is the cheapest and easiest to adapt a tbi to.

Steve

 

Does anyone else with vortec experence have anything to add or am I going to jump in with both feet and hope I can remember how to swim!!!!