[tinberwolf]

This is going to go in my sons jeep for fun in the mud, ok here is what I have done 350 block bored .60 over and clearance for 375 crank, 5.7 rods, KB flat top piston 2 valve reliefs, aluminum heads 200cc intake runners and 64cc chambers,Crosswind Dual plane street and strip 1500-6500RPM intake, 600 cfm Edelbrock, Double row timing chain set, hydraulic flat tappet lifters, aluminum roller tip rocker 1.6 ratio, cam .465 intake/.488 exhaust Duration 224/234 112deg with 1.5 rockers but as i said i used 1.6 ratio.

Well I think that's about it, So with what I have listed what might I expect to see for HP out of this and any thoughts on what I should Have done are always welcome. Thank you.

[ayers1981]

Your asking a loaded question , I can tell one thing the next guy will blast me and you and say something different . I have built and ran 383's for about 10 years . I like the 5.7 rod myself . I think for what you are doing with it everything looks good . It's hard to give you a H.P. # . Because of to many unknowns related to tuning . One horsepower per cubic inch is in reach for you .

[ap72]

I think your compression will be too high, for a 5.7" rod... at the RPM that compression will make its peak at the 6" rod will give you an advantage.



Unless you're running E85 cam is too small for the compression too.

a 6" rod will make more power in most cases but on the street you can have oil issues depending on the pistons/rings you use. a 6" rod will also lower the rotating weight, good for longevity.

[tinberwolf]

For the most part This will not see a lot of street use maybe to and from trails 15 to 20 miles at most. Thanks for the reply we where hoping to get around 350 hp you say depending on the tune what all are you referring so i can research and learn this is are first build so i need to learn all this stuff.
Also for Exhaust what would you guys recommend we have a set of outside frame rail long tube headers with 1 3/4 inch tubes.

[ap72]

What fuel do you plan on running? Do you have an idea of what compression you're at?

[tinberwolf]

this is what is on the kb piston specs Flat Top (2 Valve Reliefs 10.3:1 w/64cc
but i am not for sure, was hoping to run cheapest pump gas lol don't know if I will be able to. this is all going to be a learning process for use so please tell me what you all think. if I recall the machinist figured more like 9.5:1

[ap72]

The KB piston isn't really a typical 2VR piston, they have a huge groove running through it, which is good- nonetheless I would plan on 91 or better octane.

[my87Z]

i'm about possitive that your compression is not 9.5:1 you would need atleast a 18cc dish to get that from a 64cc head, depending on how much your motor has been deck (or if at all) you are sitting closer to above 10.5:1 (with a .040" quench) you mentioned that they are 2 valve relief pistons and not 4 so i would guess the -cc's aren't more than 5-7. and with a -7cc piston volume a .040" quench, 4.100" gasket and 64cc head i'm comming up with 11:1, you will certainly need to lower this if you want to run that cam and also run pump gas at all. i also see that you have listed 200cc heads and since you mentionedthis will be a mud truck you want more tq and shouldn't be as worried about hp, i think you would be far better off with a 180cc runner head and look into a 72cc combustion chamber this will help lower the compression to around 10:1 a little more acceptable range

i'm looking on KB's site to try and find what pistons you bought, are they hypereutectic pistons or fordged. under the hyper listings i found KB100's, KB134's, and KB253's all are -7cc valve relief pistons and all mention 11.1:1 compression with a 64cc head. if you already have all these parts you will certainly need to look into a 72cc head and try to set you quench at .050 or look for a set of world SS 76cc heads

[ap72]

KB's pistons aren't your typical 2VR's. They have an "attenuator groove" cut through the valve reliefs that adds a considerable amount to the recessed volume. He probably is under 10:1.

I've used these pistons before, kinda funky looking but they work.

[tinberwolf]

trying to find the part # not having any luck but I think it was 9906HC
block was not decked

[tinberwolf]

Brand Keith Black/KB Pistons
Manufacturer's Part Number 9906HC-060
Part Type Pistons
Product Line Keith Black Silv-O-Lite Claimer Pistons
Summit Racing Part Number UEM-9906HC-060

Bore (in) 4.060 in.
Bore (mm) 103.124mm
Piston Style Flat top, with two valve reliefs
Piston Material Hypereutectic aluminum
Compression Distance (in) 1.433 in.
Piston Head Volume (cc) +5.00cc
Wrist Pin Style Press-fit or floating
Pin Diameter (in) 0.927 in.
Piston Ring Thickness 5/64 in. x 5/64 in. x 3/16 in.
Quantity Sold as a set of 8.
Notes Coated skirt.

here is a link http://www.summitracing.com/parts/UEM-9906HC-060/

[cobalt327]

TW- There are always 383 builds going on, and actually right now, there's a THREAD on just such a build.

It, along w/numerous others are available for reading by UTSE, both here and google, other forums, etc.

One good thing about the 383 SBC stroker is there is a LOT of good first hand info available for them.

Good luck w/yours!

[tinberwolf]

I am not looking to build one I already have it built was just wondering where I might need to improve on it later or if i really goofed lol we have not got the new axles under it yet but have run it through a break in 2500 rpm 20 minutes then let fully cool down. thanks for the advice.

[techinspector1]

795.5 cc's in the cylinder (.7854 x 4.06 x 4.06 x 3.75 x 16.387)
64 cc's in the combustion chamber
3.6 cc's in the deck (.7854 x 4.06 x 4.06 x 0.017 x 16.387)
5 cc's in the piston crown
8.76 cc's in the gasket (typical 0.040" gasket required for use with aluminum cylinder head). This will put the squish at 0.057". If you're using an iron head, you can use a Victor Reinz 0.025" gasket and finalize the squish at 0.042", but the static compression ratio increases.

Anyway, all volumes added together (876.75) and divided by the compressed volume (81.25) yields a 10.79:1 static compression ratio. The thinner VR gasket will yield 11.19:1 SCR, but would improve the squish. Now, you may want to check my work, but my advice would be to fire your machinist and find one who can properly cipher the SCR for you before you buy all the wrong stuff. You're gonna need either larger chambers or larger piston crowns or both.

And don't even think about spec'ing a cam until you get the SCR nailed down. Oh, and another thing. In the first place, I would not use a flat tappet cam, but if I did, I sure as hell wouldn't use 1.6 rockers on it.

EDIT: I see you've already built it and run it. Good luck.

[cobalt327]

Originally Posted by tinberwolf

I am not looking to build one I already have it built

Between the info from
my87z, techinspector1, and ap,72 you see what you're up against- too much CR, at least for that camshaft.

Even though you've already built this engine, the same research into threads, etc. applies though, for getting it put right to run w/o detonation.

Good luck in any event.