94 Z28 block
bored out to 383
probe industries
Chevy 383 Flat Top -4.0cc - SRS Piston Set by Probe



Part Number: 12337
1.125" Compression Height
3.750" Stroke
6.000" Rod Length
0.927" Pin OD
1/16 in. 1/16 in. 1/8 in. Rings


Forged: pistons, crank, and I beam rods
Probe 5140 Machined Beam Connecting Rods - 5.700" Length
its a full stroker kit
LT1 to LT4 Conversion Kit 1994-97 LT1, Kit Includes Cylinder Heads, Hot Cam Kit, w/Rockers, Intake Manifold

plus small stuff like msd opti
hooker super comp mid tube headers
SLP 1 loud mouth cat back

what i wanting to know if what do u guys think my hp will be around thanks

 

Oh gawd...not much. You're going to plop an LT4 hotcam and LT4 heads on a 383?

Best guess...~350whp. For the price you're paying for all of that stuff you could have a 383 with 75+ more HP.

You've also got some serious issues with your parts list.

1.) You list a piston designed for a 6" rod, but then say you're using a 5.7" rod. What's up with that?

2.) The LT4 stuff is extremely overpriced and outdated. There are some aftermarket companies that are doing WONDERS with porting stock castings (see sig). You need to seriously revise your valvetrain approach.

3.) The MSD opti offers ZERO advantage over an OEM AC Delco optispark, yet is $100 more expensive. Money poorly spent here.

4.) Why mid-tube headers? Are emissions a concern?

Lots of questions to be answered here.

 

ok well im getting the heads ported anyways
and what cam should i go with

 

Send the heads to AI. They have a good cnc program in place for that casting. Let them recommend a cam for you. You'll be 100hp happier when you are done. Sell the LT4 manifold and have them port your stocker.

 

so port the LT4 heads
port my stock intake
and let them choose a cam for me and there will be close to 100hp more
that would put me around 450wrhp?

 

Care to answer some of the question posted above?

 

i dont believe you can use stock intake on lt4 heads. correct me if im wrong but your gonna have to use the lt4 intake and port that

 

If you have dont care about spending alot of on stock designed heads and then have them ported go nuts. If i were in your spot i would get rid of the Lt4 heads and buy a stock casting Trickflow or any aftermarket heads to have good basis the start. In my case i would just reuse your stock heads and send them to LE or AI to get them ported which in the long run will safe you money and perform just aswell. The LT4 intake isnt much better then stock and porting them does squat for power and can even hurt you if not done properly. The LT4 cam is a cheap cam that makes okay power for what it does but for what your already spending there are WAY better options out there and will make more power and perform alot better. Check out AI or LE and email them and tell them what you want out of your car and how you drive it and they will spec you a cam to your needs.

Without doing the calculation check on compression i would expect to have a 383 with a lt4 topend id expect somewhere in the 360hp/tq. A friend of mine did the lt4 topend along time ago and put down 350hp/360tq through a stock lt1/m6. Yeah he shouldve gone another route for what he paid but AI and LE werent really around at the time. After being disappointed with the performance he sent his lt4 heads and intake to LE for his work and a custom cam for his 383. Now puts out 460rwhp with the help from LE so right there you can see on top of a stock lt4 topend you would likely gain 75-100rwhp! Yeah it can be done but all depends what you actually want to spend on your build or what you can save and put into other parts/mods to your car.

Hope this helps!