Another 383
 

I know.. another 383. My first, and all the threads I've found seem to be years old and none of the reference links work anymore.

I'm building a 383 with standard bore (..so a 377) in a 94 z28 a4.

Balanced eagle kit.. Cast crank, I beams, and KB -18cc pistons.

AFR 195CC eliminators 54cc combustion chambers for 10.5ish to 1 comp. (Saving for the idea of nitrous one day)

LE 230/238 .565/.565 110 LSA

42lb bosch injectors/340lph pump

Performabuilt stage 2 w/ 2500 stall

pacesetters/ORY/SLP


My questions:
.stock intake manifold enough for this setup?
.what kind of air intake best? I've seen talk about the ls1 lid
.Would anyone recommend running a wide band to keep an eye on air fuel ratio with the new injectors and pump?
.Is the factory fuel pressure regulator going to do OK with that pump?
​​. Would anyone think a better stall converter to be a good idea? Maybe a yank or something a little better than the no name 2500 i have?
​​​.do i still need the factory crank pulley on top of the underdrive pulley with a balanced rotating assembly?


Thanks For your time!

Re: Another 383
 

Heads out of the box or ported? Stock intake is fine if matched to the heads by a quality head porter.

Do a search on the Eagle cast crank. Questionable quality NA. Out of the question w/ nitrous.

Is your U/D pulley an integrated pulley/damper like the ASP, or a sandwich style pulley that mounts with the stock damper. The stock pulley is not a balancer. It is only a neutral balanced damper. In any case, the setup must include a damper, not just a pulley.

Ask LE about the stall, but 2,500 seems too low.

Re: Another 383
 

Afr heads out of the box.

Bbk aluminum underdrive pulley, looks as if the factory one fits on the front of it.

I've heard that about the cast cranks so I will keep it in mind. Hold off on nitrous.

le did say about getting another stall. And that the quality is more important than the number itself. I could go with a 2500 if its a good quality converter. Which I doubt mine is.

thanks for the reply!

Re: Another 383
 

As a member of the 2 piece Eagle cast crank club on a NA motor...I would STRONGLY encourage you to go Scat forged at a minimum

Re: Another 383
 

Did you buy the heads already? If not, LE can get the same results porting your stock heads, along with the intake manifold. Less $$$


That is a "sandwich" style U/D pulley, requiring the factory damper to be used. There is very little to be gained with an U/D pulley on the LT1 engine, because the water pump is not driven by the serpentine belt. Here's a dyno that shows a gain of less than 1 HP. And that's for an integrated type, which weighs less than the sandwich design. IMHO they add more problems than they solve, particularly with an auto trans, where you typically have a lower programmed idle speed. That can lead to a weak battery, and that's the last thing you want on an engine that relies on electric power for the fuel pump and the injectors.

Drivetrain Modifications #2


In particular, the Eagle is junk. I'm glad Chimera96 gave his feedback. I was just trying to be diplomatic and not overtly trash the Eagle crank.


I'd guess 3,000 RPM would be the minimum, but ask LE. I'm no auto trans guru. I have an ATI converter, but the shop that built the engine selected it. It's designed to flash to 5,000 RPM when the 800 lb-ft of nitrous hits.

Re: Another 383
 

Thanks for the replies. I might send this crank back and get a forged kit. As far as the pistons, the guy at jegs, who seemed knowledgeable, more so than I on stroker kits to be honest, recommended -18cc's matched with 54cc combustion chambers for around 10.5:1 comp. Is this even worth my time? Not really gaining any more compression, not sure of the power difference?

Thanks

Re: Another 383
 

Did you check the compression ratio calculation, using an online calculator? You'll also need the deck clearance and compressed gasket thickness.

How did you get away without boring the cylinders? I had a decent used block, and we went 0.020" (381ci) over to preserve cylinder wall thickness, based on sonic measurements. Went for 10.8:1, but ended up a bit higher when we had to take a couple thousandths off the heads after they were ported to keep them flat. There are no huge gains with higher CR, and depending on the cam specs you can get into trouble with pump gas octane vs. detonation. That gets into calculating the dynamic compression ratio, and can be affected by the altitude you live at, and the octane of the available fuel.

Re: Another 383
 

OP

I have yet to find any online "tech" selling car parts have a clue on a Gen2 LT1. Because of their reverse cooling they can run higher compression than a regular Gen1 SBC which they seem clueless on so spew stuff out that is just wrong

Eagle forged crank is low end but "ok"...Scat is a step up and what I did. Top shelf would be Callies. On pistons you want to get a quality forged one that is not stupid heavy....like cranks you get what you pay for. SRP are decent. Mahle likely better

If it were me I would send your stock LT1 heads to Lloyd and get a cam from him based on your intended HP goals...but understand bigger cams move the max HP levels higher up in RPM range so for "street cars" you need to get something that has good manners and performs without having to spin the motor to 7k rpm to make it. Discuss with Lloyd

The whole build needs to be a plan, not just buying label parts. Quench, how much the block needs to be decked, head gasket thickness, chamber size, etc, etc.

Re: Another 383
 

Tons to reply to here. Love it thanks guys.

I had the cylinders checked at a local machine shop. They told me they looked great. They honed them for me, grinded the block and threw the cam bearings in.

I did the online calculator while ordering the heads, so did the guy I was on the phone with. We used the recommended gaskets for the CR.

Scat is not out of the question for me, maybe I'll check on those instead. Keith black pistons are what I currently have ready to install, but I can do some looking at the brands mentioned.

Also I already ordered the heads. So I called up LE.

As far as the cam goes, I spoke with him - hell of a guy btw - and told him the setup i had, and he recommended 230/238 .565/.565 110 LSA.

Re: Another 383
 

LE is pretty amazing. He will not only take the time to talk about your setup and what he recommends, but will get into the detail of why if you ask. You might want to talk to him about porting your intake, the full job is $200.

Re: Another 383
 

I'll look into it thank you