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Discussion Starter #1
Hi everybody.

First, I'm not an expert and I'll probably be wrong about a lot of things. I'm here to learn :)
I have a 383 stroker built in 2005 (I bought the car with this engine) :
- 383 scat crank 5140
- 4340 scat rodes
- 9.8-1 keith black pistons
- 256 - 264 solid flat tapet
- 1.6 rocker
- Dart heads 230cc
- edelbrock victor junior
- 9.9 compression

A compression test shows a good 175psi on all 8 cylinders.

As you can see it is a street/strip engine with a lot of cam and too big heads, 195 or 210 would have been enough.

I'm using it on the street, it is not the perfect combo for me and I want to upgrade it.

What I want/how I use it :
- street only
- I'm running E85 only, it is way cheaper where I live
- As E85 is cheap, I don't care about mpg
- My car is a manual (3.7 rear axle)
- I want maximum area under the curve
- 500hp/tq are my dream numbers (I don't know if it is realistic)

I thing I need something like the medium specs on this article : https://www.hotrod.com/articles/ccrp-0808-383-stroker-small-block-chevy/

In order to keep it cheap, I would like to keep my heads, even if they are too big.

What do you think of :
- increasing CR to 11:1
- smaller cam ~235/240
- roller cam

Thanks :smile2:
 

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Fabien,
I dont know what you have available to you in France but the first thing I would tell a customer here would be to put the car on a chassis dyno and see what you have right now. I would not be a bit surprised that your present combination is very close to the numbers you want.
 

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I agree with Bill. But if you have access to 100+ octane fuel you can go with more static compression pushing 12.5:1 domed pistons at 0.040" overbore (you are at 0.030" now). This is free horsepower but requires a high octane fuel like alcohol to keep you out of detonation. Your current combination is more race than street but it is also a big small block (Chrysler considered a 383 to be their baby big block) that compensates for your lack of bottom to mid range torque.

Reducing head port size while retaining your current valve size will give you more bottom end torque but subtract from that horsepower number unless you are willing to rev it higher (your solid cam with 1.6:1 rocker ratio allows this to happen if you bury your foot to the fire wall. The down side is that cam robs Peter to pay Paul (there is no free lunch). You are shifting the power curve into the higher RPM, but if you are not willing to drive around at WOT (or the gendarme will not tolerate that behavior), then you are wasting the power you need for the street with your current long duration cam. You would benefit from a shorter duration hydraulic roller cam.

Big Dave
 

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What do you think of :
- increasing CR to 11:1
you will need a minimum of 100 octane and 110 is better
I just went through this . 9.9.9-1 to 11-1
 

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What do you think of :
- increasing CR to 11:1
you will need a minimum of 100 octane and 110 is better
I just went through this . 9.9.9-1 to 11-1
He's using E85 so he likely had the octane covered but no idea what it is in France. In the US, it can be a bit of a crap shoot I hear on exactly what the blend is and can be as low as 70% alcohol. Before I went to 11:1 I would want to make sure I could trust my fuel source.

I get the bit about wanting to save money, but I think I'd have to get rid of those heads for a street motor. The 195 AFR CNC's heads seem nice but they aren't cheap. I'd get rid of the Victor Jr in favor of an RPM Air Gap and go with a hydraulic roller came in 280+ degrees of duration and over .500 lift. Keeping then 1.6 rockers will give you more than advertised lift. I'd probably just leave the pistons as is. You didn't say how big the chambers are in the heads but going to a smaller size would give you a little bump in compression without needing to pull out the pistons. Not having to buy new pistons means you can spend elsewhere. You can probably sell those heads and the Victor for a decent price. If I was building a SBC to race, I'd probably be interested in something like that.
 

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You can sell the motor you have and buy a street friendly crate motor with a warranty and be money ahead.

Buy an engine based on how you really use the car. Torque is key on a street car. Forget about advertised peak HP #s.
 

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Discussion Starter #8
Fabien,
I dont know what you have available to you in France but the first thing I would tell a customer here would be to put the car on a chassis dyno and see what you have right now. I would not be a bit surprised that your present combination is very close to the numbers you want.
Hello Bill. You are right, we have chassis dyno and it is a good first step.

I agree with Bill. But if you have access to 100+ octane fuel you can go with more static compression pushing 12.5:1 domed pistons at 0.040" overbore (you are at 0.030" now). This is free horsepower but requires a high octane fuel like alcohol to keep you out of detonation. Your current combination is more race than street but it is also a big small block (Chrysler considered a 383 to be their baby big block) that compensates for your lack of bottom to mid range torque.

Reducing head port size while retaining your current valve size will give you more bottom end torque but subtract from that horsepower number unless you are willing to rev it higher (your solid cam with 1.6:1 rocker ratio allows this to happen if you bury your foot to the fire wall. The down side is that cam robs Peter to pay Paul (there is no free lunch). You are shifting the power curve into the higher RPM, but if you are not willing to drive around at WOT (or the gendarme will not tolerate that behavior), then you are wasting the power you need for the street with your current long duration cam. You would benefit from a shorter duration hydraulic roller cam.

Big Dave
E85 octane is a bit tricky.
You guys in the US use AKI octane rating (=RON - MON / 2) on your pump (93 in the US = 98 in France because we use RON rating) but when you speak of E85 it seems you are speaking MON rating?
E85 is rated ~95 AKI in the US and 96 AKI in Europe.
Are we ok with that?

Build for torque, its what pegs your 'Seat-of-Pants' meter.
I agree.

What do you think of :
- increasing CR to 11:1
you will need a minimum of 100 octane and 110 is better
I just went through this . 9.9.9-1 to 11-1
How do I do that?

He's using E85 so he likely had the octane covered but no idea what it is in France. In the US, it can be a bit of a crap shoot I hear on exactly what the blend is and can be as low as 70% alcohol. Before I went to 11:1 I would want to make sure I could trust my fuel source.

I get the bit about wanting to save money, but I think I'd have to get rid of those heads for a street motor. The 195 AFR CNC's heads seem nice but they aren't cheap. I'd get rid of the Victor Jr in favor of an RPM Air Gap and go with a hydraulic roller came in 280+ degrees of duration and over .500 lift. Keeping then 1.6 rockers will give you more than advertised lift. I'd probably just leave the pistons as is. You didn't say how big the chambers are in the heads but going to a smaller size would give you a little bump in compression without needing to pull out the pistons. Not having to buy new pistons means you can spend elsewhere. You can probably sell those heads and the Victor for a decent price. If I was building a SBC to race, I'd probably be interested in something like that.
My heads caractristics:
Material: Superior iron alloy
Comb Chambers: 64cc
Intake Valve Dia: 2.08”
Intake Port volume: 230cc
Intake Port Dim: 2.230” x 1.260”
Int Port Location: Stock
Intake Gasket: Fel-Pro# 1206
Exh Valve Dia.: 1.600”
Exh Port volume: 82cc
Exhaust Port Dim: 1.380” x 1.400” w
Exh Port Location: Stock location & bolt pattern
Exhaust Gasket: Fel-Pro # 1405
Flow, Intake: 308cfm @ .700” lift / 28”
Flow, Exhaust: 207cfm @ .700” lift / 28”

You can sell the motor you have and buy a street friendly crate motor with a warranty and be money ahead.

Buy an engine based on how you really use the car. Torque is key on a street car. Forget about advertised peak HP #s.
I forgot to mention that I need to change my cam (I think it is used by the flat tapet : my valve lash was .1" the first time I checked it) and at least one of my rockers (one broke).
Maybe i could just put a 240 ish roller cam. Try it and if I don't like it, sold the engine to a racer.
How much does my engine worth in the US?
 

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Had a similar build (406" SBC with that cam, but a solid roller) and on the street can be a bit much.

Your 500/500 dream can be had, as that motor may be close.

For street-ability, and those numbers, I would look into a power adder like a turbo or supercharger of some sort.

Big numbers on the street are just numbers if you don't/can't use them, and can make it tough to drive. As above sad....build it for torque (it's what moves you) and let the HP fall where it falls.

Something else....higher octane fuel in a motor that doesn't need it CAN reduce power output.
 

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I agree with Doug and Everett, build for torque. I would rather have 475 lbs of torque and 300 hp than 475 hp and 300 lbs of torque. The torque is what moves the car and gives you that seat of the pants when you pour the coals to it. Years ago I used to believe deep gears and rev it up to the stars but they were little motors. One day a dear friend and competitor machine shop built a real nice 406 for his 69 nova. He came by my shop smiling from ear to ear and said take my car down the access road and let her rip. when I came back I was smiling more than him. these days I build for torque and larger cubes. a wise man once said the only replacement for cubic inches is cubic money or more cubic inches. Alex
 

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Discussion Starter #11
Okay. With my setup, how can I do that the easiest way?
If I need to buy another engine? Can you give me examples?
 

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Compare these engines. They share common head size (190 cc intake runners with 2.02 intake valves) and a hydraulic roller cam with a miserable 9.2:1 static compression to run on American pump gas.

This is a GMPP motor (built and warranted by Chevrolet in America as a brand new Chevy engine, not so sure in France):

https://sdparts.com/i-24080712-blueprint-engines-bp3830ct1-base-long-block-383-with-vortec-heads.html?gclid=EAIaIQobChMIzdv2r93e6QIVGonICh1yrwaaEAQYAyABEgLl6PD_BwE

Normal Vortec heads are only 170 cc intakes but the "Bow Tie" version (and it doesn't mention which version they chose to use) is 190 cc in size. (I recommend a 190 to 210 cc port size as bigger isn't better for the street).

Here is another example using cheap brand X Chinese heads.

https://www.speedwaymotors.com/BluePrint-383-Small-Block-Chevy-Roller-Crate-Engine,60536.html?sku=91533383&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=EAIaIQobChMIzdv2r93e6QIVGonICh1yrwaaEAQYAiABEgKq7_D_BwE

These engines make just over 400 horse with 440 to 450 foot pounds of torque.

Note the cam specs on the second engine. That should be your never exceed maximum for duration for a street engine. But even then it requires a 2,500 RPM stall converter to be drivable.

I recommend duration on street engines to be split but no longer than 218° on the intake and 224° exhaust on a 108° or longer lobe separation angle (bigger the LSA the quieter the cam sound as there is less overlap).

https://www.amazon.com/Chevy-1958-95-Roller-Camshaft-MC22135/dp/B07L57H7GK

Here is a brand X cam and you can compare the numbers and the engine characteristics. Keep in mind most cars have rear gears of 3.07 or lower (two series gear). I don't know what you have but; the higher number means the higher the cruise RPM will be. You use gearing and the engine's torque to get you moving (gears multiply torque, and torque is what accelerates the car up until you loose traction).

Big Dave
 

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FWIW, on that Blueprint Engines 383, everyone seems to report that they make more than the advertised power. I just got their 355 with those heads and it was advertised at 390HP and the dyno sheet they sent had 403 at 5900. The curve was still going but they shut it down, I assume because that engine wasn;t really intended to go higher than that.

If your block and rotating assembly is fine, stick with what you have. Different heads, hyd roller and different intake will probably get you want you want. More cubes would definitely be fun though but you'll have to move to something more like a 400 block. Blueprint makes those too. You can get more displacement from the LS line as well.
 

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Discussion Starter #14
Thank you. I'll think calmly about this.

In all case I need to change my rockers, they are cooked.
Is it a good idea to get 1.5 rockers instead of 1.6?
Do I need to change the pushrod consequently?
 

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Thank you. I'll think calmly about this.

In all case I need to change my rockers, they are cooked.
Is it a good idea to get 1.5 rockers instead of 1.6?
Do I need to change the pushrod consequently?
PR length would be the same....but "cocked" RR?...the roller end should be centered on the valve stem assuming these are NSA RR and you have guideplates. ISKY makes "adjustable" guideplates to allow independent alignment of the int & exh valve per cyl. if the "cocked" RR is not landing on the valve stem centered
 

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Discussion Starter #16
The roller is centered.
What I want to know is if I change my rocker ratio from 1.6 to 1.5 do I get more low end torque as it kind of "decrease" my cam?
 
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