350 TBI vortec head swap and smog questions

[Steve95]

I want to put a set of vortec heads on my 350 TBI motor. My questions are:
How will my mpg be effected? I'm imagining it will increase with the better flow of the vortec heads?
Will it pass smog? I drive it daily, would be nice to pass smog at a normal place.
Will all aftermarket headers for the TBI motor fit?

I may build my first motor and swap in to my '94 Sierra. I also have a '97 suburban 4wd lifted on 33's (usually on 35's). It has a vortec 350 that's bone stock with a little tune and it totally stomps out my '94 2wd on smaller tires. The GMC is my DD right now, but will eventually be a toy.

The whole smog thing is confusing to me. I can get my truck smog'd, but id rather not pay $200 every time. There are ideas of a newer LS swap floating around in my brain for this truck too.

 

[Mdauch]

I'd also LOVE to know this if anyone cares to share.

 

[TylerZ281500]

depends how smog is from what ihear, visually you might not pass, if egr and everything is hooked up you should pass in a perfet world. mileage and power will increase youll feel a difference thats for sure. building from the bottom up is alot of fun but shop around first. if your doing heads on just a plain jane tbi motor then your cam will limit it so now you be the time to put all your balls into one basket and do it right. also a tune should be datalogged and made for the engine, dont leave your trans hagning with a beefed up motor though.

with vortec heads tbi headers should all still fit.

 

[whyteboy97]

about to do the vortec heads on my 95 tbi. i was wondering if the stick tbi will be ok with just a chip. or get a high flowing tbi like cfm-tech.

 

[TylerZ281500]

ultimate tbi mods and both spacers will do just fine, chip would be best if your camming it too and so on

 

[Mdauch]

If this is too complicated then just say so but: What kind of tune should i be looking to do?

 

[TylerZ281500]

datalogging is your best bet, or find a local tuner good with tbi and obd1. hypertech, tbichips, jet, etc are a waste for these trucks. the only proper way to do it is datlogging it yourself or having someone do it for you because theres too many variables to suggest one chip for every truck.

 

[Mdauch]

Another question with these heads: My family happens to be great friends with a local junk yard, they have a couple SBC Vortecs and i was wondering since i could probably get them for free, is if the intake manifold directly bolt up or would i have to buy a specialty one. Also what should i have done to these heads to get them reconditioned. Such as valved, shaved, magnafluxed, etc. I'm very inexperienced with heads

 

[ccreddell]

You absolutely dont want the Vortec intake manifold. I used a Edelbrock 2116 and a TBI adapter on mine. But, do get the roller cam parts from the Vortec and when you swap in a cam get a roller one-like an LT1, or LT4 cam. As far as the heads, just a good valve job does fine in a fairly stock truck. Alex's parts has valve springs that allow you to get the lift you need without machining.

 

[Mdauch]

Thanks I appreciate it, should i shoot for shaving to get a better combustion ratio? I'm a machinist so it would be free, might have to buy an operator lunch but pretty much free. Also I was told my engine was bored .30 over no way to tell (yet) is this going to affect anything?