I'm in the process of tearing down a motor, and I'm considering possible choices. I was thinking maybe TPI, since I already have a TBI computer, and that can be made to workl for TPI right? I also saw LT1 intakes and such. Are these legal? My car will be my daily driver, and will be inspected, and fuel economy is an issue also. But I'd like fuel injection. I was also thinking of 383, would a carb be the only induction setup to feed a 383?

 

You can't run a carb and expect to be smog legal either. Not unless you have lenient smog laws/inspections

 

Do they do a visual check? If so, I'm gonna say no.

 

Why wouldn't it be legal, they use it on 4th gens and it's completly legal?

 

No one has done it yet. If you take the TPI corvette for example, the EGR has an outside system. SD vortec intake has the parts to make the same system work. How it works, you ask? The EGR system, instead of running through the ports in the head, uses a piece of piping to route it up to the rear of the intake manifold. I am pretty sure that it how the 4th gen cars do it. The LT4 intake uses the same piping but has the EGR system inside of the manifold, somehow. Please double check the LT4 system, for I am not 100% sure of this. If someone was to come up with a way to do it, people would purchase more intakes. I'm sure that John Millican will chime in shortly, I have had many conversations with him on this.

The problem is that the EGR is on the rear of the intake, it would need to be removed for use with the distributor. That is why it wont be street legal and wont be legal with visual inspections. Some people just use the block off plate on the old TPI systems and have passed the emmissions test. Your choice.

 

Well here it wouldnt be legal, because that intake was never available on a normal SBC engine. You'd have to sell it to the state guys as a SBC with a LT1 intake (that'd never work), or as an LT1 engine (which might work, but unlikely).

I dont know how it works up in your neck of the woods.

 

Are LT1 intakes legal?

If you are refering to a LT1 intake on a SBC then the simple answer is "no".

As you may know the EGR valve and external exhaust feed needs to be removed to make room for a standard distributor. So if you have a visual inspection you will fail.

There is a good chance you will also fail if you put a carb on there as well since it wasn't available in your car model year.

And as far as LT4 intakes and EGR system, I have no idea. I have never seen a LT4 intake in person but I suspect it has the same EGR as a LT1.

 

Well, so if it didn't come in my car stock, it isn't legal? So, I'm guessing a Superram wouldn't be legal either huh? I ask this, because I'd like to build a 383, and I'd like EFI with it. Those are the only options I've seen that would support a 383. Is this right? If not, forgive me, I'm still learning. Thanks

 

Superram is, because they jumped through the legal hoops (read:lots of cash payoffs) to get it approved.

 

The SuperRam is smog legal because it hooks in to all the smog equipment the same way that the factory unit does. The LT1 intake is not for the reasons just mentioned.
You could put a NEWER motor in your car (such as a complete LT1) and they would have to smog it based on the specs for that motor but you can't put earlier equipment or parts that were never made for that car (i.e. Can't put an L98 in to a 4th gen). What state do you live in and how tough are the inspections?

 

Have you considered making a High Flow TPI setup instead?
That'd be completely legal.

Port the upper plenum and portmatch to runners

High flow runners of course (SLP siamesed or Large tubes)

Aftermarket base like the bigmouth/edelbrock or maybe even the Superram base.

I imagine a tpi setup consisting of these parts would flow as good or damn close to the popular aftermarkets (stealthram, superram, lt1, mini etc) Also, I happen to think that the long tube runner system looks badass, especially when polished up!

 

I live in Texas. So, a superram and a high flow TPI would be
legal? I can imagine a TPI would, because it came in our cars. But the superram is also? Well, if I do all that you said to a TPI system, wouldn't it cost as much as a superram? You can't tell my 'older' 350 from a newer one from the outside right? So the fact that I would have an older 350 in my thirdgen wouldn't matter right?

 

If you have ever bought items like the Superram or high flow parts, you'd know that it comes w/ a sticker that must be in plain view to the emissions *****. The sticker identifes the part and gives its CARB approval number. I have one for my Trick Flow heads and my Superram lower intake manifold. Thats how these parts are smog legal. Of course I don't have emissions are inspections where I'm from, so I don't know why I saved them...

 

Yes a high flow TPI system would be legal even under visual inspection. Since it's stilla TPI setup, and looks stock to anyone who isn't into thirdgens... I dont imagine a visual inspector would notice different runners/lower intake mani.


Aftermarket runners - 250ish
Aftermarket base - 450ish
Ported Plenum - "Free"

250+450+0 = 700 give or take.

Superram = 1100 give or take

400 means a lot to me i dont know about you =)

 

I can agree with the $450 for the base, and the $250 for the runners, although $250 is for the SLP runners, which are cheapest ones out there by far (I don't know how they compare performance wise though). I do know that if you go with the same brand of runners and base, you will get better matched performance and ease of installation. Personally, I would get the plenum professionally (ensure a quality job, besides, porting mistakes are very costly), most places who sell TPI stuff do the porting work on an exchange basis for about $100.

If you already have a computer, you can get the Stealth Ram for $550. Keep in mind that the Stealth Ram is not emissions legal and I've heard that ported plenums with the EGR walls knocked out have trouble passing smog as well. I'd say that the SuperRam is the best way to go, but it's pricey ($1200). It's up to you. Personaly, I think that the Super Ram is the best, but I want to pass smog, so I'll probably get a SuperRam.

 

I am from TX too and I have a TPI in my monte carlo SS. It is amazing what these guys will pass. The inspection guy did not even take a second look or say anything about it. All the smog equipment is there and it is completely street legal.

The super ram is the easiest way to go and be street/emissions legal. D stroy H8 shows the difference in price but did not mention the "tuned" difference of the "stock" style TPI vs the super ram. Super ram has shorter runners which has a different "tune" giving it a higher RPM HP peak. The super ram is much better suited to track applications. A ported/aftermarket TPI system is better suited to more power in a stop light to stop light application of just out cruising. HTHs

 

Sorry, make that:
Personaly, I think that the Stealth Ram is the best, but I want to pass smog, so I'll probably get a SuperRam.

 

The LT4's don't use an EGR....something to do with the camshaft and its design.

 

Well yeah the Superram is better, I don't disagree...

However the TPI stock style with portmatched plenum/runners/base, SLPs siamesed OR large tubes, edelbrock base OR superram base I think would hit some high RPMs comparable to the Superram, and also keep all that nice low end torque just like the Superram.

So what Im saying is - A high flowing stock style TPI setup would perform nearly as good as a Superram.

For nearly the same amount of money. (400.00 less)

 

So if what you are saying is true, then a p&p TPI system would flow up to ~5500rpm. I have a little trouble believing that. Can anyone with ported TPI show some dyno numbers?

 

Not just ported and polished.

When I say 'High flowing TPI setup" I mean Aftermarket base and runners. No way will the TPI ever perform close to a Superram with stock runners and base.

The aftermarket offers runners that can literally SWALLOW a stock runner, and bases that flow MORE than a fully ported stock base out of the box. If you want, you can FURTHER port out an edelbrock base or a bigmouth from TPIS.

So the question is - Do I think a ported upper plenum portmatched to SLP's siamesed runners which are in turn portmatched to an Edelbrock lower manifold would perform nearly as good as a Superram?

The answer is - Yes. Yes I do.