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vortec heads on a 1990 350??

snowdriver

snowdriver

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i will be rebuilding my 1990 tbi 350 this winter,and from what i have seen the vortec heads will bolt on,will the stock tbi and ecm be able to adjust to these or is there something else needed,i am not looking for huge horepower for this rig,but i want what i can get reasonably,and what about camshafts that will work with the tbi system,and this still has to pass emissions
 
tbi manifold will have to be welded to raise the ports to match the vortec's...I believe the bolt pattern is different also.
 
That would take serious mods to the factory intake to get it to work i would think. GM offers an intake with all emissions hookups that convert Vortec heads to the throttle body. No adapters required. You might have to have a chip though, and most likely raise fuel pressure a bit, as them Vortec castings outflow the TBI ones quite a bit.
 
You can use the heads, no issues bolting them on, then either get an aftermarket intake, adapter to bolt the TBI to said intake. Or I think someone makes a TBI/Vortec intake. Would need some ECM work, the worst Vortec heads flow better than the best TBI heads....if there is such a thing...
 
will have to resaerch a intake that will accomadate the tbi and bolt onto the vortec heads,did any of the vortec engines utilize the tbi setup??
 
There was a rumor on the net about 1995 1 ton vans had a vortec headed motor but with TBI. I saw a couple in junkyards and they were regular TBI. I think the only thing using a regular 4 barrel intake with an adapter is the lack of EGR. But with a custom chip that can be eliminated.
 
Yes there were Vortec headed TBI units, as the calibration for the ECM is out there. Obviously not real common or you'd find them more often.

4 barrel to TBI adapters are somewhere around $20 (summit sells them) so that is a viable option. No idea if reasonably priced aftermarket Vortec TBI intakes are sold.

You will most definitely have to get it tuned. Even if it seemed like it ran ok, an emissions test will quickly find otherwise.

Where are you located in OR? One of the guys over on gearhead-efi.com does custom tuning out of Vancouver.
 
make sure to get vortec head gaskets, and use a water pump bypass also.
 
I was going to say something about the water pump bypass, but as long as you aren't running a valve on the heater core (did any of our trucks use those? I've never seen one, maybe the last couple years?) the bypass is already there IMO.
 
I ran a simple loop from the front of the intake to the top of the waterpump...
 
Unfortunately my new radiator is going to take that spot up, but normally yes, you can run it that way.

Still, aren't most of our trucks heater setups plumbed as a "bypass" anyways, even if that was not what it was intended for?
 
No. Although Vortec heads work really well, they are still a somewhat low RPM head, simply based on the runner size. I'm comparing them to all-out racing heads, but the point is, they make very good power "under the curve", which is where a normal truck needs it. The stock throttle body will promote good velocity at lower engine RPM's, which helps keep the fuel atomized as it travels through the intake.

You could probably pick some top end up using the BBC TBI, but I don't think I'd do it if you need/want low end, or you had no real need for all your power to be up high.
 
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good,i am looking for good low to medium rpm power,not building a comp eliminator:D :D just need a bit more towing power and a stronger pull at hi-way speeds
 
I bet if you spend some time over at gearhead-efi.com you may be able to find the "bin" (it's the programming on the PROM, what some people refer to as the chip) for a similar vehicle to yours. I know there is a TBI/Vortec timing table floating around over there.

Timing alone won't do it, but if the timing table is there the whole thing probably is too. Do you have headers? That's another noticeable increase in power that complements better heads too.
 
it will have headers when i finish it along with true dual exhaust ,cats will be removable:whistle:
 
You might consider finding a set of world products S/R torquer heads. For the cost of the vortecs, intake manifold, etc... you'd probably be even, or better. I've bought used torquers for a few hundred bucks in good condition. You just have to look around. They'll yield a very similar improvement to the vortecs, but the casting quality is much better.

Just some food for thought...
 
If your state does emission testing and part of it is a visual then you will probably fail the test using Vortec heads since the EGR would either not be working (unless you also buy the EGR kit) or they may just fail you since the emission equipment has been modified. I would start asking your local emissions test centers some questions about what you want to do and if they would fail you on that alone or visit your local state referee on the subject.

Also, the last I knew the special required Vortec to TBI intake was close to or just over $300 alone. Keep in mind that Vortec heads will only accept about .450" lift cams factory and if you're going bigger then other work will need to be done to the heads first.
 
I'll second the aftermarket heads. Last I knew you could get castings with good chambers, good flow, and overall good parts, with the exhaust crossover and "older" bolt pattern, which would cut down on certain costs, and as mentioned, emissions complications, if a factor.
 
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