twin turbo sbc 383 help
 

Hi, Im new to the forums here... Anyways my father in law gave me a smoked 355 to tinker with (blown head gasket and 4 spun rod bearings). Well the problem is I have never built a muscle motor before, I was all about the imports. My first thought to do with this motor was just build a simple 383 since all the work to the block has already been done. Although after doing some research I want to mix the import and muscle into one motor, example being variable lifters wich from my understanding would basically make whatever heads I bolt to this beast act as vtec heads, I think that would be pretty cool... As far as the build I am lost. So what Im asking for is a parts list of what Ill need.. Also this motor will be going into an 89 iroc z with the tpi (port and polish of course).

I know I need 2.02 heads, brand ????? 3.75 forged crank, 5.7 or 6.0 rods? inverted dome pistons or flat top?

I need some help here, I used to taking ka24's, sr20's, b16+18's, h2xa's and just slapping forged internals in them. Port and polishing the heads, high flow exhausts, and running 15-20 psi of boost through them.

My goal for this build is 1000+ hp, with twin 68mm turbos running at 1 bar of boost (14.7)...

I was right there w/you... until the last line! lol

Good luck w/that.

Im tryin to figure out how that would be a problem??? Can the sbc not handle that high of boost or what? Ive seen a couple builds online that are running 8-9 psi and are hitting 915+hp...

It's not that it's not possible- it's that it's beyond my experience.

That said, my opinion is that an OEM block will not cut it. Actually, I'd be surprised if there were ANY OEM parts involved, period- unless the length of the fuse was of little concern.

I have no doubt that this block can handle it. When this motor was being bored 30 over it broke the machine shops hone twice. All I know about this block is its from the early 70's, 4 bolt main, and its a mexican block. Anyways Im still needing help on a parts list.

So far what Ive put together is,
Scat procomp light weight crank (6.0 rod)
Dart 2.02/ 1.60 heads, 72 cc cumb chamber (to help lower compression for higher boost)

Still need help building the parts list

Yeah. Like I said, good luck w/that.

As I said I am looking for help on the build, so far all you are providing me with is frustration...

Wow....

I don't think anyone is trying to frustrate you. What you're looking for is something that people here may not have much experience with.
While your build is interesting, it's not something you can do without quite a lot of money (not to mention experience). Variable valve timing aside, building an SBC to take the boost levels you're looking for is going to require a very good builder and a lot of money. There is a reason professional racers will spend $20k or more on their engine.
Building a 1000hp SBC may not be too hard, but building that same power level and having it be reliable is a whole new undertaking. It can be done. However, I agree with cobalt. If you're going to run that kind of boost and those power levels, IMO the OEM block isn't going to cut it.

It is hard to provide help in this case since your idea is helpless...nothing personal just my opinion. No one can bring this motor together with a OEM block I don't care how many honing machines it broke :spank: if it could be done then you would get all the help you needed here, I admire your willingness to bring it to the table though...

Nothing against anyone in here, but from what Ive been reading on here not to many people have played with boost.. Going with a final CR of about 7:1 there should be no problem pushing 12+psi. As I said earlier I have built many import motors in the past running 15+ psi. Dropping my CR will allow me to succeed in pushing more boost. I was reading a TT 383 build on a different site where the guy used an oem block pushing 9 psi and is having no problems yet. The twist I am trying to accomplish (VVT) may throw a different degree of difficulty into the build, but running VVT will actually prolong the life of the motor. Yes I know this is going to cost me a arm and a leg to build, but if I can succeed Ill be happy. Ive got a few custom auto shops helping along with this build as well. One of them being a shop that all they specialize in is boosting the impossible, their latest project was an srt10 viper that they twin centrifugal super charged pushing 13psi on the STOCK BLOCK. Like I said I am just looking for a parts list of good/premium parts to build this motor with. I know a bunch of people have built a few 383 in their day, this is my first...

what does the specialized shop say about twin turbo'in a oem block?

Your experience is with very small bores, short strokes, very light rotating assemblies and very high revs. When you get into the dynamics of pressures in big bores vice small bores, you can see that the big bores require cylinder walls that will withstand the extremely high pressures generated. Then you have to think of containing the much more massive rotating assemblies that are going to have to rotate at a much higher rate to make the horsepower you are talking about. An OEM block just is not going to cut it. Don't care if it is a tired old early 70s, bore tool breaking block made in Mexico(???). You just can't rewrite the laws of physics and rules of metalurgy to achieve unrealistic goals. But go ahead and knock your self out.

Trees

Do it.

With a low compression ratio there is nothing holding me back from pushing 12 psi. A little more work is required to get my 15 I looking for but it can and has been done with retained reliability. Even with 10-12psi my projected hp at the crank is between 950-1010. I also have most of my parts list put together finally after many phone calls throughout the day.

Even if it takes me a year to complete this project Im going to do it just to show what limits you can push a OEM sb to. Also its not like this car/motor is going to be race only (hence the VVT). Like I was always told; where there is a will, there is a way.

Im not sure if you guys are telling me it cant be done because either you have tried and failed, seen others try, or just scared to attempt it? Im surprised out of everyone that has posted none of you have encouraged it, only shot the idea down. Isnt building motors about trial and error?

I quote: "As you wish, sir. Will that be cash or charge?" LOL

But really, what is the name of the shop who says "Do it"?