L98 383 engine buildup

[Coupe de jour]

I have a 91 coupe that I am planning to upgrade. I came across an intersting goody in the 2003 GMPP catalog. It is a 383 with 425 hp. It uses the 383 short block with the fast burn heads. Rather than go thru all the trouble of getting my stock L98 upgraded this sounds like a great option.

1. Does anyone know if the fast burn heads are compatible with the stock TPI base or the TPIS big mouth base?

2. Also, this engine has a lot of cam and I have to worry about smog since I live in California. How much cam can I get by with and still pass smog?

3. Is this engine compatible with the ZF-6 speed?

My ultimate goal is big torque. I live in an area with lots of great windy roads so accelerating out of turns is a kick. As a result I operate the car almost always in the midrange rpm. My plan was to mate the engine above with a TPIS big mouth base, non-siamese runners, and plenum as well as a complete exhaust with 3" cats. I was considering a cam with about 210 deg @ .050 and around .500 lift.

4. Can I go for more duration without killing the bottom end.

Thanks for the help,
Coupe de jour

 

[69MyWay]

Unless your engine is just plain worn out and ready for a rebuild, I suggest you look into putting a super charger on your car. That way, you get 40% more power, cool under the hood looks, and you can pull it all off in one weekend and stay emission legal.

The 383 would be great...except, there is no way it is going to be smog compliant for a variety of reasons.

It won't bolt up to your L98 intake, and there are no aftermarket intakes that have the EGR still in them (required emissions part).

The cam is way too radical.

By the time you invest in a new intake, fuel rail, computer calibration, sensors, etc....you will sink a fortune in it, and it will take you months and months to get the finall programming down straight...and it still won't pass emissions.

YES, the good news is that it will bolt right up to your ZF, no sweat.

Now...go find a cooooool super charger with intercooler for that bad boy, and get to spanking some curves in a hurry! (as well as a few mustangs, and anything else that gets in your way).

 

[-=Jeff=-]

It won't bolt up to your L98 intake, and there are no aftermarket intakes that have the EGR still in them (required emissions part).

Scoggin Dickey Chevrolet makes a TPI Base the bolts to the Vortec and Fast Burn Heads.

TPiS Makes the Minram 3 that bolts to them as well

 

[69MyWay]

Scoggin Dickey Chevrolet makes a TPI Base the bolts to the Vortec and Fast Burn Heads.

TPiS Makes the Minram 3 that bolts to them as well

agreed, but neither will be C.A.R.B. compliant..right?

 

[vader86]

There is no set limit to the 'amount of cam' you can have. But, the 210 setup youre suggesting can easily pass WITH tuning. Whatever duration/lift combination you have has to be factored in with intake and heads, then the front portion of the exhaust, the duration itself wont hurt the bottom end. The intake cant breathe enough air to rev high enough to put you in serious danger.

I know though that the Accel 74219 cam has CARB #'s with the Superram intake (which does also).

I would not use the fastburn heads unless you already have them. The stock heads will be just fine, although porting would be in your best interests with a 383 underneath.

A 383 will pass emissions with the Superram and 219 cam. PROVIDED you keep the stock exhaust up to the main cat. There are no CARB legal longtube headers, shorties though are available. (i just cant remember who makes them)

The ZF6 can handle the torque output.

I would do the Superram, 219 cam, 383. That should get you close to the 425 goal and still pass emissions, with tuning and stock exhaust. (catback you can change)

 

[69MyWay]

Yes, it can be done, but I don't see it simply by buying that 425 crate motor. The CA smog Nazis are tough to get around.

He would be better to stroke out his own short block, then work on all CARB legal parts from there out.

 

[-=Jeff=-]

agreed, but neither will be C.A.R.B. compliant..right?

Not sure on the Vortec TPI Intake, it does have an EGR and all the Emissions stuff. But you could probably pass inspection with it

and the Miniram is not CARB compliant.

 

[Coupe de jour]

Thanks for all the great feedback. I had previously considered a supercharger. Maybe I'll do both!!!

When I was looking in the GMPP catalog at the fast burn heads intake runner view there appears to be two sets of bolt holes for intakes. On top is the four hole set-up for the Vortec and on the bottom looks like the traditional six hole set up. My TPI base has six bolts holding it in. Is the reason it won't fit because of raised runners or just the geometry of the base?

It sounds like I don't need to worry about cams other than proper PROM calibration as long as I keep my choice reasonable.

It was mentioned that I would need to keep the exhaust stock on the 383 for smog considerations. Was that because of emmissions performance or simply because the exhaust parts did not have a CARB exemption number?

Thank again for all the help.

 

[vader86]

There are no CARB legal longtube headers, and you will not pass sniffer with them either, unless your county is fairly lenient and you have a very good main cat.
They will fail visual.

Shortys are available with CARB numbers, however any Front Y without the precats will fail visual. It may or may not fail sniffer, provided the main cat is good, depending on the county restrictions.

 

[86PACER]

I agree. I installed long tubes when I lived in North Carolina. When I moved back to Cal, it would fail the visual inspection. Even though it passed the tailpipe part of it. My only solutions was to temporarily swap them back to stock.

 

[Eagle85C4]

Pace Parts has both Edelbrock intakes for stock and vortech heads. Both are priced a bit over 300.00...

 

[Coupe de jour]

I found these headers at TPI Specialties. They come equipped with air injection manifolds and EGR tube provisions. That will be enough for them to pass smog here in California since they do not defeat any of the original smog devices. I tried this on my Chevy 4X4 with a SB 400 and a set of similarly equipped Doug Thorely tri-y's. I passed with flying colors and the truck ran extremely clean. The tech was surprised. As for the rest of the fuel injection setup, their super ram does not have an EGR provision so I will go with the big mouth base, large tube runners, and ported plenum.

Have a Merry Christmas

 

[coop]

The price of that engine is $6500, I wonder how much it cost you to build your own motor?

 

[tntcorvette]

For $6500 ide rebuild with a excellent engine builter and may have money left over. Can you do the work yourself?