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Discussion Starter · #1 ·
Alright fellas i need some help, ive got this 383 4bolt bored .040 (actually a 384.45 or something) but i have these 601 castings fully ported n polished 1.94/1.60 and 53cc.. And i cannot find any pistons for the damn thing. is it going to be impossible to get workable compression with the stroke and this small of a chamber? ive called summit, eagle, cnc motorsports and a couple others and have been told im pretty mutch screwed and will need to buy some vortecs or something with a larger cc.
 

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I don't know what c.r. you're looking for, but these pistons will result in 9.75:1 c.r. figuring a 0.040" overbore, zero deck and an 8cc gasket (0.040").
http://kb-silvolite.com/performance.php?action=details&P_id=91
Using a cam with an intake closing point around 40 degrees after bottom dead center should make a pump gas runner if you have built a tight squish into the motor. Counsel with the tech guy at your favorite cam grinder.
 

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I would go with Vortecs anyways. I wouldn`t build a 383 just to choke it with 305 heads. Unless the chamber has been deshrouded the larger valve won`t help flow any. The Vortecs have a redesigned chamber that unshrouds the valve, the chamber is more efficiant and best of all the 170cc intake runner induces great swirl characteristics in stock form. And to me you can`t get any better than that a bolt on head you didn`t have to do any work to.
 

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Discussion Starter · #5 ·
yeah i hear ya.. they are the 305 heads.. weres the best place to start looking for some vortecs? which ones do i need to look for/avoid? ive heard porting and polishing them can actually hurt the performance of the head.. any truth to that?

if i buy them bare, how much in parts am i looking at? Im thinking i will have to go alumminum to be safe when i hit the 100-150 shot of giggly, right?
 

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Years ago I got a killer deal on a set of RHS Vortec heads that were bare. Being a I had a set of Manley streetmaster 1.94 1.50 valves I was ready to roll. If your shooting for a 9.5:1 compression ratio you won`t have any issues running cast iron heads even with nitrous. The RHS heads are heavy casted and not light like the factory castings are. I scored mine off ebay for a little over $400. They also flow better than do factory castings.
These are great heads, the power they give my best friends street 350 is outstanding. If you want aluminum heads you can go up on the compression ratio by another half point being aluminum cools faster than does cast iron.
 

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Discussion Starter · #7 ·
So if i manage to get a 9:5 to 1 c/r with some vortecs, the cast iron will be sufficient with a 150 plate nitrous system? i was talking to a gent at a shop and he said i would need to bring my c/r way way way down, like so far down i wouldnt even think it would move, he said like 7:8 to 1 or something rediculus.

so 350 4 bolt 3.75 stroke bored .040 over. vortec heads like 64cc?
also was going to go with a comp solid cam .477 lift
150 plate nitrous system, roller rockers. what size carb?

Also, with the vortecs and nitrous, will flattop dome or dish be better/stronger? just anything that will bring me to 9:5? thanks for the help fellas..
 

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53CC heads using flattops piston or -8CC for eyebrow on a piston will yield 12:1 compression. That is too much. :nono: You have to change to -30CC dish piston to get the compression down or get 76CC Heads. It will give you 9.3:1 compression. Good Luck
 

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Nope, you don`t need compression that low to run nitrous. Turbo`s and super chargers have to have low compression. We`ve ran a 350 horse big shot plate system on a 11:1 compression 400 small block without issue. I hope the guy who told you that don`t do a build of his own, as it sure would run crappy off the bottle with compression at 7:1. He must be another one of those that think nitrous stays on all the time. Scroll down on the link and it`ll answer your question about compression ratio`s and nitrous.
http://www.nitrousexpress.com/Pages/carb_faq.htm
 

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Discussion Starter · #11 ·
do i need to go with flat top, dome or dish with the nitrous? i will bring my c/r down to about 9:5 so i will run a 200 shot instead... if it is a plate system can i have a computer or something on it so i can set when the nitrous kicks? sometimes i might want to have it spray right off the line and other times like when im driving on the street i will just want to have push buttun if needed. is there a computer out there to allow it to spray say a 50 shot after shifts and also have the push buttun? im new at this no2 thing so any help would be appreciated. Also i was looking at the RHS vortecs.. yay? nay? 64 or 76cc? o yes thanks for the link i learned alot from it, still alittle fuzzy though, would like to talk to someone with experience.
 

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Discussion Starter · #12 ·
Also, i have my eyes on a 2 speed powerglide.. i get mixed remarks when i mention this name, i will be running the car 1/4 and 1/8.
350 4bolt stroker clearenced bored .040 over
scat 3.750 crank forged.
5.7 rods forged.
not sure on pistons..
comp solid cam with .477 lift
76 or 64cc rhs vortecs
not sure on intake and carb..

Does this sound like something to spend my time building, or am i going to be dissapointed when it all comes together? ThanKs FoR ThA HelP!!
 

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Discussion Starter · #15 ·
not enough power? what kind of power do you think i will be making? I was thinkin this build would be up there..? 76cc with flatops 200 shot of nitro 750 dp and a single plane? 385 ci? with a .477 solid lift cam? do i need to get a stall and a bigger cam or what? but back to the original question.. how much power do you think this thing willbe putting out?
 

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Well, with a 200 shot I could see right under 700hp being possible. But you really haven't got one part to build at that power level, you MAY be able to use your harmonic balancer bolt, but that's probably about it. You could make 700hp once or twice, but for it to really be used at that level you need to step up on all your parts.
 

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whatsamotor said:
Alright fellas i need some help, ive got this 383 4bolt bored .040 (actually a 384.45 or something) but i have these 601 castings fully ported n polished 1.94/1.60 and 53cc.. And i cannot find any pistons for the damn thing. is it going to be impossible to get workable compression with the stroke and this small of a chamber? ive called summit, eagle, cnc motorsports and a couple others and have been told im pretty mutch screwed and will need to buy some vortecs or something with a larger cc.
Go look at Kieth Black they have D cup hypers with a choice of 12, 18,or 28 cc cups. That makes 10.8, 10.1 or 9.2 all of which can be fudged around with gasket thickness and deck milling if necessary.

Bogie
 

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Discussion Starter · #19 ·
So no nitrous huh? boo.............
i would like to have a 50 shot atleast when i jump off the line.
Could i not get a controll box and set it to just have a small steady mist?
just for an extra push?


maybe im being alittle hard headed here and just want to see the nitro when i pop the hood but ive always wanted to run something with nitrous, and am not going to be seen in a rice burner.

So your thinking around 485-475 ponies huh? thats plenty to spank on most street cars i suppose... :evil:

will the RHS vortec 76cc be the best head for that price range for my app.?
Ive been looking on ebay and have found plenty of reasonable deals.
Thanks for all the help fellas.
 
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