Hey I was just wanting to know I have a 350 with a Qjet carburetor. The engine is out of a 84 G series van so I know the heads are crap but I am wanting to possible put vortec Heads on. The heads I might get are off a 2000 Chevy 3500. So is it worth it and will they work together? Thanks

 

You will have to get a different intake, but if it's worth it depends on price. It will really wake up that engine though.

 

Ya I know about the intake I looking at an Edelbrock Performer Vortec Intake. Do i need to worry about compression or clearance issues?

 

These are the best bang for the buck short of nitrous, do them. Shouldn't have any clearance issues, if the pistons are stock you should be around 9:1-9.5:1.

 

If you have the tools time and are willing to call it "good enough" you can use a non-vortec specific intake for a budget build.

It looks like your going my route and buying used OE heads so you will have a few issues to contend with.

All it takes is a little planning with your ultimate goals in mind.

#1 You will have to determine if the heads will clear your cam/rocker combo. The only way to know for sure is to measure the clearance your self on the heads you will be using. If it's close you can use a set of locks to raise the retainer assemble a bit. I believe the figure is around .050" , be sure that the self guided rockers dont hit the retainers or locks.

#2 spring diameter clearance. The one or two conical spring pn's available actualy work well with a broad range of street roller cams and flat tappets, since they fit the stock spring pocket's they are worth consideration.

If you cant use any of the options above because of your cam selection then you might want to invest in a tool available from several companies that enlarges the spring seat, narrows the guide boss and lowers the guide all in one motion allowing you to run larger springs and more lift.

And that will likely bring you to point #3. Studs.

Stock pressed in studs proably wont last if you need to do the alterations listed above so investing in another tool specificaly for drilling and tapping the stock stud bosses for stock style screw in studs is a good idea.

Do a couple of your friends heads for a small charge and your sure to makeup for the cost of the tools and you'll still be spending less than what a shop will likely charge.

"Performance" studs require milling the head and most people cant do that in the garage. Thats the reasoning behind using OE style studs when you can.


Some people are sceptical of Vortecs because if you pay out of pocket to have everything done and add the cost of the special manifold they claim you are too close to a basic set of aftermarket alluminum heads that flow much more to make them worth it.

What they dont consider is the fact that these "basic" heads are old tech, with old style chambers and runners.


A good set of aftermarket heads with chambers that are as good as vortecs "let alone any better" are in an entirely different price bracket.

 

I don't mean to hijack the thread, but I am in the process of putting 5.0L Vortec heads on my Firebird with a 305 TBI. I am going to keep the TBI no matter what, but I am looking for a cheap manifold that will fit under my hood.
I have heard that for one year only (1996) that G-Series Chevy Vans came with Vortec heads and TBI; same thing with trucks made in Mexico during those years. Is this true, and do they have EGR provisions?

 

Those 96-98 YM Trucks with TBI and Vortec heads DID NOT have EGR and it was eliminated in the Chip. Marine engines had an even nicer intake manifold and 454 size 2" bore TBI.



This underhood shot is a 1998 Grand Blazer (rebadged Tahoe) with the Vortec TBI 5.7. Notice the 96+ vortec era alternator, compressor, and brackets.

 

Beautiful!


I guess you learn something new every day lol, I never knew this.


I had been thinking about converting a TBI manifold to multi point with a cadillac TB (late model 4.9's came with port injection and a TBI style TB without the injector pod and resulting gaping hole) but I still want to run Vortecs. TBI manifolds looked to be more dificult to fit to Vortecs than TPI bases and the EGR location would have interfered with the fuel rails, injectors and lines.


Was this only available outside of the US or did US spec 96 Vans come with this manifold?


PS, it looks like it could be modified for a carb if you were really on a budget.

 

I am going to buy the heads first and am hoping to have them machined for lift. I have access to a mill and cnc machine, Think you guys could help me out with what tools I would need. As for the cam and intake I was going to buy these after the heads are done. Hoping to match the intake and cam to whatever is best with the heads. Any idea's for what would work best. Thanks

 

http://www.jegs.com/i/Comp+Cams/249/4726/10002/-1

This is the tool that reduces the id of the boss and increases the od of the pocket.

Search around Jegs and Summit and you'll find tools for machining the upper guide for both height and other types of seals.

And since the intakes specificaly for the Vortecs are limited heres a trick I picked up.

Besides the drilling and/or tapping required to mount non-Vortec heads you also need a certain minimum overlap at the top of the ports to compress the gasket.

Finding somebody that'll lay a couple beads on an aluminum manifold isnt that hard or expensive but having the manifold milled afterward's can be.

Just bold a strip of relatively thick copper plate to the manifold flange and lay several overlaping beads. The aluminum wont stick to the copper and tha copper will leave the weld nearly flat with the rest of the flange.

A few minutes with a large flat stone with fine sand paper over it will yeald a flat flange that'll seal perfectly.

 

That does it. I'm going to Mexico today and hit the junkyards until I find one of those manifolds.
I'll let y'all know what I find.

 

Ok, I went by a bunch of junkyards in Reynosa and Rio Bravo, Tamaulipas today, and those manifolds don't exist. All of the Tahoes and pickups from those years had regular Vortec manifolds.

 

AH, YEA they DO exist!!!! They have to be MEXICO production for the MEXICAN market...Not ones brought in from the US. I even have the stock PCM calibration on my truck for one. $63 ECM Code