Hey guys...I recently made the decision to build a 383 stroker EFI for my TA. I want a car that feels extremely powerful when I drive it on the street in the real world, stoplight to stoplight conditions with some nasty curves thrown in. I want something that will still be way fun to drive on a daily basis if I want. I did a search and am having a hard time deciding which parts to get in order to have a well matched motor for my purposes, so I figured I would just ask and tell you what Ive decided on so far. I plan to spare no expense for this motor as I am stretching it out over a few years. I am a newbie to this so I am trying to learn as much as I can about which parts I need to make this build happen and I want to price this all out.

Here is what I am looking for:

-Street and strip uses
-2200 to 6200 power range, I basically want a happy medium for torque and horsepower, I dont need a giant torque monster motor or a super high revving 7000 rpm screamer, just something that makes its power low to mid and still pulls very strong up to 6000 so it is driveable.
-I am sticking with naturally aspirated

As far as the options I have already picked out....

-L98 350 block .030 over 4 bolt main 1 piece main seal- gotta track one down
-Crower 4340 forged standard crank - summit # CRO-E95125X4
-Full Holley Stealth Ram EFI kit (will be slightly ported) - summit # HLY-91404201
-Comp Pro Magnum roller rockers- summit # CCA-1305-16
-Eagle H beam 6.0" connecting Rods- summit # ESP-6000B3D
-Forged or Aluminum pistons - I want to use dished pistons due to the better burn properties
-Hydraulic roller cam- still researching on lift and duration numbers
-Comp Pro Magnum hydraulic roller lifters- summit # CCA-875-16
-AFR heads-not sure on size
-1 3/4" ceramic coated headers with dual 2.5" into a 3.5" single all the way back to the muffler splitting into dual 3" out the back
-Street filled block

What I am looking to find out:

-Which size AFR heads should I get whether it be 195cc, 210cc, racing, street, etc...in order to match the pistons and achieve the compression ratio I want.
-What is the most useable horsepower I can muster out of this motor without revving out past 6200 and keeping it somewhat controllable for street use? Im ok with sacrificing some driveability for performance, but I dont want all straight line power. I was thinking a 2800 or 3000 stall or so on the tranny.
-Do I need to get forged pistons, if so which ones?
-What compression ratio will get me the power Im looking for?... I was thinking 10.6:1 and with the gaskets it would lower to around 10.3:1? That way I could use 93 pump gas.

I know I asked a lot of questions that may be a little vague so please just answer what you can and I will greatly appreciate it. I have been around motors and cars forever and know alot about them but matching parts and building a good flowing, powerful stroker is not something Ive dove into yet. I said it earlier but Ill say it again I want to get the best of everything for this motor. With this project Im going big or going home, and home isnt an option. Thanks in advance for any help.

Adam

 

You don't need the expensive hard parts to go fast, they don't make any power and hurt the budget and are not needed in your case.

Use the trw/speed pro L2491 piston, afr 195 or trickflow heads, stealthram, slp headers, scat or eagle cast steel crank and I-beam rods or the h-beams made for the stroker. I ran the LPE 219 cam with the TRW pistons listed above with 5.7 gm pink rods and 400 crank turned down and the cam cleared the rods no probem.

Use the 3000 stall convertor and a 3.42 gear. I ran mid 12's at 110 mph with the 383, lpe219 cam, afr 190's, slp headers, 3500 stall and 3.27 gears and superram. Passed emissions and was a great driver, but torque on the street was a tire-burner.

You could use any of the comp 224-230 intake duration cams with a 112 lsa and you can pass emissions and have good driveability.

 

Im not really concerned about emissions, this is not my daily driver but more of a fun car for the street and sometimes the drag strip (if I wasnt so clear I apologize).

If I go with the AFR 195cc heads do I get the 74cc or 68cc model?

 

"L98 350 block .030 over 4 bolt main 1 piece main seal- gotta track one down"


L98's only came in 2 bolt main i believe, but u can still get a 4 bolt main roller cam 1pc rear main seal block and its basically the same only with 4 bolt main instead of 2 ....... like the zz4 block for example

 

Bowling's Compression Ratio Calculator
Input Parameters Are the Following:
Cylinder head Volume (CC) = 76.00
Piston Top Volume (CC) = -3.40
Cylinder Bore (Inches) = 4.0
Cylinder Stroke (Inches) = 3.75
Deck Height (Inches) = 0.015
Head Gasket Thickness (Inches) = 0.026
Computation Results:
Computed Compression Ratio is 10.7 to 1


Use the big chamber heads with the victor reinz head gasket which is 26 cc's compressed or the gm head gasket which is 28 cc.

 

I would look into Rotating assemblies for your 383, once you decide whether you are going forged or not. You can find them from hyperpistons, i-beams, cast crank for like $700, and all forged w/ h-beams for $1400. Either way they have what would suit your needs and save you money. You would be happy w/ the AFR 195's especially w/ the powerband you are looking for. Plus as for picking up a block....you could always pick up a 2bolt main block....since it needs to be line bored you can have splayed caps installed at the same time. Oh, and good luck with the build.

 

Ok I got a few more things figured out as far as the engine build goes....So here is a rundown of the full combination so far:

Pistons- JE forged flat top pistons

Crank-Crower Forged 4340 3.75" stroke

Rods- Eagle H-beam 4340 6.0"

Block- ZZ4 street filled

Lifters- Comp Pro Magnum hydraulic roller

Rockers- Comp Pro Magnum roller 1.5

Cam- Part #12370846 GM high performance cam- dual pattern with .509/.528 lift (in./ex.) and 222/230 duration @.050 lift with 112 degree lobe separation. I plan to do some of the cleaning up of the heads myself.

Intake-Holley Stealth Ram full EFI kit

Heads- AFR 195's (how many cc's?) Looking to get a final installed compression ratio between 10 and 10.2:1 to run pump gas safely (93 octane)

Exhaust- 1 3/4" ceramic coated LT headers with dual 2.5" into a 3.5" single all the way back to the muffler splitting into dual 3" out the back

TQ- B&M Holeshot 2400 (should stall at 2500 with the stroker)

Trans- Beefed up 700R4

With the cam I picked out and the rest of the parts I am hoping to have the power start building strong around 2000-2500 and pull through 6000. The SR intake specifies being able to flow until 6000 rpm. From what I can figure it would peak at around 5500 and Ill set up the shifts for 5800-5900 with the rev limiter at 6000.

What I still need to know is what size chambered AFR 195's to get to achieve the 10 to 10.2:1 compression ratio with flat top pistons?

Any more opinions on my future setup would be greatly appreciated and thanks for all the help already.

 

I think you can do better than the B&M Holeshot converter.

 

I second that. Not for the reason most people do, insisting they are junk. I dont have a problem with thier converters, they have never failed me. That just isnt the right converter for the package. I would use no less than a 3000 stall. Look for something in a 10" converter, not a 12".

 

Smaller diameter TCs also have much better "street manners".

 

Im not too familiar with all the different types of torque converters. What would you guys suggest for this motor? As far as I could tell with the cam choice the best rpm stall would have been 2500, but I may be wrong? What brands do you guys prefer over B&M and how does the 10" converter compare to the 12"?

Also is there a formula you guys use to determine the compression ratio based on the cylinder head size and the use of domed, flat, or dished pistons?

 

Ok, lots of variables to figure your c.r.... Here is an example: 4.030 bore, 3.75 stroke, flat tops w/-5 cc valve reliefs, cometic head gaskets @ 4.065 bore & .040 compressed thickness, 74cc chambers, .020" deck clearance=9.55:1. Change any, n change the c.r.! Do a google search for compression ratio calculator. I downloaded EngineCR, works great, even has a free limited trial!

 

In a perfect world, a cam that has a 2000-6000 power band would be perfect with a 2500 stall, but it just isnt so. There are so many variables when it comes to stall converters. You have a reasonably mild cam, I would go with a 3000 stall, if it were me. Something in a 10" converter.

 

Hey man one other thing, I would recomend running a bit higher compression ratio than 10.2:1, I know you want it pump gas friendly, but aluminum dissapates heat so quickly you really need to run 1 point more compression to have all advantages of aluminum heads, weight and power! I would shoot for around 11:1 w/ those heads and that cam, you can still easily do that w/ a flat-top piston, and will be totally pump-gas friendly. If you are set on that cam you can get all the specs on it, and check for dynamic compression ratio, which will affect its ability to run on pump gas more than static compression ratio will. You will want a dynamic ratio of 8.5-9.0:1 to run on pump gas, and get the most out of your new engine.

 

12secformula, I'm curious bout this dynamic c.r. with my setup, 60cc chambers will give me 11.2 static n w/"847" cam, a dynamic of 7.88.... this good, bad, or indiff?? This is an LT4 383 stroker, all forged w/AFR195's. Enlighten me, O' Knowledgeable One! (OMG, were r all the smilies?) Thanx in advance!

 

12secformula, I'm curious bout this dynamic c.r. with my setup, 60cc chambers will give me 11.2 static n w/"847" cam, a dynamic of 7.88.... this good, bad, or indiff?? This is an LT4 383 stroker, all forged w/AFR195's. Enlighten me, O' Knowledgeable One!

 

Well I am also relatively new to the wonders of engine building, I stumbled upon this information while reading up on all sorts of onfo, about building matching engine combinations. Now first off I will not tell you that I am entirely correct in my thoughts, but I will say that my conlusions are fact based inferences about the information gathered. You said that your static compression ratio stands at 11.2:1, which w/out second guessing is what many of the other people may recomend you to run if they do not know what cam, etc you are running. However w/ a cam that size to get the most power and efficiency out of your engine you would wnat between 8.65-9.0:1 dynamic compresson ratio. Now with that said you have a few options to get your ratio changed to something more optimal, you can advance or retard your cam, get a higher static ratio, or get a different cam. Before anybody jumps on my back about this post I have gathered alot of this info from some very talented cam designers and engine builders. I must say I have seen my fair share of people who set out to build the perfect matched combo and have missed the point about this, static compression doesn't mean dick.....dynamic ratio is what is most important. Also I have seen multiple people run 12.5:1 static ratio on pump gas, and I'm sure People might challenge that, but its true. You can run that if everyhting else matches and the dynamic ratio is where it needs to be. This is one of a few major points in engine designing where people lack the knowledge or choose not to care about which leads them to wonder why there engine is a "turd". Also Z92maro I believe your combo should run very well, but if you want to get the most out of it, make sure the quench and Dynamic ratio is perfect and you will have a monster.

 

How would the following setup work for still running on pump gas?

Bore 4.03 (inches)
Stroke 3.75 (inches)
Rod Length 6.0 (inches)
Cyl. Head Vol. 68 (cc)
Deck Height 0.025 (inches)
Head Gasket Bore 4.166 (inches)
Head Gasket Thickness 0.026 (inches)
Piston to Cyl. Wall Clearance 0.003 (inches)
Top Ring Land Height 0.25 (inches)
Piston Dome Vol. 0 (cc)

Dynamic Stroke 3.434 (in)

Dynamic Compression Ratio:
10.075 : 1

Compression Ratio:
10.912 : 1

Bore / Stroke Ratio:
1.075 : 1

Rod / Stroke Ratio:
1.6 : 1

Total volume:
863.088 cc's

Compressed volume:
79.099 cc's

I found this calculator at http://www.smokemup.com/auto_math/dy...ion_ratio.php. I want it to be on the safer side seeing as this will mostly be a street car, I just want to be able to fill up with some 93 and go.

 

85_TA_WS6, thats the one I'm using! The biggest prob I'm findin is the cam timing. I'm using a GM 847 cam, using the no.'s from the Crane clone, intake @ 79deg atdc(?), I think? This is @ .004", not .050", this the right value for this calculator?

 

I just went through your post quick, but I doubt that your piton dome is 0 cc's, do you have flat-tops? If so, I am sure you have valve reliefs in them, find out what the volume of these relief "eyebrows" are, that is your piston dome volume. That will lower your DCR, and SCR. If you really have 10:1 dynamic ratio, it will NOT run on pump gas.

 

what DR will run on pump gas?

z92maroo I got my numbers from my cam and the desktop dyno. I used 40 degrees and duration at .050" lift. I think that is what you were asking.

 

9:1 DCR will run on pump gas.

 

Ok I just called JE about my piston choice. They informed me that to run on pump gas with all of my choices in parts, I will be looking at this piston: JE/SRP Summit part # SRP-138093. They run about $499 for the pistons and $133 for the rings. They are flat top and JE said I should have a 10.17:1 static compression ratio.

 

While DCR is very important to engine building and should NOT be overlooked, SCR DOES mean a lot. The idea behind DCR is that a long duration cam will bleed off cylinder pressure, thereby reducing the amount compression the engine sees. This is true to a certain point. When you start sticking your foot into it, the SCR comes into to play. With the engine winding up so high (say at WOT, right before you shift), you are getting maximum cylinder filling (no more bleeding pressure). You are untilizing the full duration of the cam and your SCR comes in full force be it 10:1 or 12:1.

I'm not great at explaining things, but an ideal example would be a Pro Stock car. Some of these guys are running upwards of 18:1 SCR with huge duration cams (more than we'll ever see). So they should be able to run pump gas, right? Nope. These guys are running huge octane numbers because they are running at WOT all the time; they're utilizing all that compression. If they were to run pump gas, they would be out of a job real quick.

Sorry for all the blah, blah. Go here to read up on DCR and then download the CR calculator at the bottom of the page. I would recommend AFR 195s w/ 68cc heads. If you run flat tops w/ -5cc reliefs, a "0" decked block, and a .040" gasket, you should yield a 10.59 SCR.

Given your desired RPM range, I would suggest something like Comps XR282 for the cam. This will yield a 8.32 DCR. Quite doable on 93 octane.

 

theno1prince: That was a pretty decent post you have there, however you are assuming that I don't realize that someone running around 18:1 could run on pump gas. Nowhere was that ever said.....Also, I fail to see the point of most of your post, were you trying to prove me wrong? We are talking about a street engine here, not some pro-street setup. I said you could he could run on pump gas w/ 9:1 DCR, and you recomend somethingn at 8.4:1.....pretty close, but at 9:1 he would maximize his benefits. I told him he should raise his compression because of that, and the fact that ALuminum heads dissapate heat so quickly that, naturaly w/out say around 1 point more compression he may actually give up some performance over an Iron head. Any disputes there?

 

The point I'm trying to get across is SCR does affect engine performance. It does not rely solely on DCR. The example of an 18:1 compression was only to show that a high SCR will require more octane even if one is to try to "tame" it with a super-high duration cam. The point of my post was not to question your competence; I apologize if I came across that way.


This is what I recommend as a general guidline for a street/strip engine given aluminum heads (yes, my own personal opinion; not a requirement) : 10.5 SCR, 8.5 DCR, .035-.045 quench area. Some may feel this is a tad conservative; however, this will allow you to run a tight timing curve without having to worry about pinging on those hot summer days.

 

Yes, I understand that SCR affects performance a good deal...however my point I have been trying to make is that....SCR does not affect the ability to run on pump gas like it is so comenly thought. And my point is not meant to tame the cam, it is meant to work w/ it. Although your idea may be conservative, it is about the combination....and that's why it will work well. It was apparent to me that 85_TA_WS6 was not shooting for a miild setup, that he wanted more. I am trying to tell him that, with a large cam....that I believe he may choose to use, he can retain a higher compression ratio and it will match. Now if he was gonna use a peanut cam....then I would say, yeah run 10:1, but not in this case. He must want a fair amount of power because he is getting a stealthram, AFR heads, and Stroking the engine. Once you decide the cam you want, you can have the block "0" decked, that will also yeild you a higher SCR, and tighten the quench.