I currently have an L03 in my car. I want an engine that will give me 300+hp and get 20+mpg. I have seen many of you do it. I have looked in my area for an L98 and can't find one. The LT1 swap has too many conversion factors for me. What I have decided to do is start from the bottom and build up a block. Here is the plan:
Vortec Heads (mildly ported) and Manifold
ZZ9 Cam (hear it does well with gas mileage)
24Lb Injectors

My question is about the intake. What would be a good choice? I want to use some sort of EFI. I've heard about tpi intakes not having a good powerband. I know some have ported them and seen good results. I have been thinking of buying the whole setup ported if i can find one. Is there anything better for what I am trying to do. Remember it's a street car. I just want to have that power available to me when I want it, because this L03 isn't cutting it. I pay insurance to drive a "High Performance Vehicle" and right now it's deffinetly not one. Help me make it one and still get good gas mileage.
Thanks
Wes

 

The TBI forum is a much better place to find information about swapping engines under TBI. I suggest you start with the "Budget 350" sticky in the top section of that forum.

Stock Vortec heads won't handle the lift of a ZZ9 cam. sdparts.com has Vortec heads modified to handle that kind of lift. They also have a package that includes the heads and a TBI intake manifold.

 

I was thinking of loosing the TBI and going for TPI or some other EFI.

 

I'm kind of a fan of running what you've got - unless you go radical like an LS1, but you already nixed the even easier LT1.

Switching to TPI would be a little easier than LT1. But, I thought you said you couldn't find an L98 engine. Unless you have a TPI set-up available (engine hardware, harnesses, ECM, fuel pump), you're in for a lot more work with TBI->TPI than you are from 305 TBI to 350 TBI, for about the same amount of power. The break-even point would be a lot farther out with TPI than it would with 350 TBI - if there ever would be a break-even point.

TBI wasn't a "bad" system, it just wasn't maxed by the factory for performance. The aftermarket went after the sexier TPI upgrade market. Holley & others make stand-alone EFI systems that are TBI-type systems, if that says anything.

 

Thanks alot. I did read about the budget 350, after I posted that. I guess I just based all TBI on the L03. That is probably a common mistake. I will try to follow that thread. After all it is cheaper and probably better than what I would have come up with. So Thanks again