anti-ballooning convertors

Remember me? Respect? Your disagreement with my post,maybe you should read it again.Two way street with respect Leviakashock.I will not respond back to any post directed towards me on this matter.Cleanup your language or stop posting.  WIEDER  

WOW, I MUST HAVE MISSED ALL THE EXCITEMENT WHILE I WAS AT WORK.THIS IS NOT ROCKET SCIENCE.IM BUILDING A 305 FOR MY EL CAMINO RIGHT NOW,VORTEC FACTORY CASTINGS(WITH MINOR WORK)LUNATI CAM,EDELBROCK INTAKE,HOLLEY 650,FRESH FACTORY SHORTBLOCK(WITH ARP ROD BOLTS)NX 150 SHOT.NOW MY CAR IS ALL ORIGINAL (1980)AND I WANT TO KEEP NUMBERS MATCHING BECAUSE THE CAR IS MINT CONDITION WITH ONLY 90,000 MILES.I SHOULD SEE 325-350HP WITHOUT SPRAY AND THAT IS MORE THAN I CAN REALLY PUT TO THE GROND WITHOUT MODIFICATION TO SUSPENSION.NOW I WILL BE USING LIMITED SLIP DIFFERENTIAL BUT A STREET CAR WONT NEED MUCH MORE THAN THIS TO KILL MOST STANGS AROUND HERE AND IF NOT ENOUGH OPEN THE BOTTLE.JUST REMEMBER,ITS NOT WHAT YOU GOT BUT HOW YOU USE IT AND ON THE STREET THOSE FIGURES ARE A LITTLE OVERBOARD BUT WERE ALL ADULTS SO GET OUT THERE AND REPRESENT.HOPE I DIDNT HURT ANY FEELINGS ABOUT THE MUSTANG COMMENT,I USED TO OWN ONE BUT IT SO MUCH FUN CATCHING THEM OUT ON THE STREET AND LETTING THEM KNOW THAT THEY GOT SMOKED BY A PRETTY MUCH STOCK 305.              FOOD FOR THOUGHT,HOFFY  

what are you talking about dude?  you were the furthest person from my mind.  

i guess you don't comprehend well. and what does you posting one of my loses on the board have to do with anything?  i never said that 800hp wad walk in the park i just... you know what never mind this is ridiculously immature and i said before that i did not come on this forum to argue with people.  i am over this.  and if you think you are cool because you found one of my loses to post keep looking you will find more and also double the wins.  

all i did with that post if i am thinking of what you are actually referring to, all i said was that i disagreed with you,  thats all, how is that disrespectful?  i am confused as to your way of thinking.  

this last post was directed toward Weider.  i am not sure why you just busted out and told me what you did but i don't know why and ...  

Hoff mayer,

sound like a sweet camaro, mine is not like that mine has like 160,000 miles on it it is a 1991 rs.  It was given to me for free with a hole in each side of the block big enough to put a fist in.  so i got the bottom end out of a 1985 z28 with the 305 h.o. flat tops and put my heads intake and tbi on it with an cam and a lot of other stuff.  I am making 320 hp. if you want more info on my car i would love to trade info back and forth.  but any way i just wanted to let you know i don't have matching numbers i just want to see what i can do with a 305 because no body likes them.  i want to push it to its limit and if/when it blows up i will take off all of my good parts and pout them on a 383.  that is my entire plan in a nutshell.  

YOUR RIGHT ABOUT NOBODY WANTING TO RUN THE 305 BUT THE BOTTOM LINE IS ANY THING CAN BE BUILT BETTER,AND IM A FIRM BELIEVER IN NOT SPENDING A FOURTUNE ON THESE ENGINES.BECAUSE THEY REALLY DO HAVE A FEW SETBACKS.THE TWO MAIN PROBLEMS ARE SHROUDING OF THE VALVES AND THE POOR CASTING MATERIALS USED IN PRODUCTION.THESE BLOCKS ARE SOLID INTO THE 500HP RANGE,BUT MANY OF THE 350 BLOCKS ARE ONLY GOOD INTO THIS RANGE AS WELL(UNLESS YOU HAVE A NICKEL BLOCK,THEN YOU COULD TACK ON ANOTHER 200HP WITHOUT SWEATING).AS LONG AS A GUY IS DOING A LITTLE REALISTIC PLANNING HE CAN BUILD A POWERFUL 305 WITHOUT BREAKING THE BANK.AND THATS WHAT STREET RACING WAS BUILT ON,GETTING THE MOST OUT OF WHAT YOU GOT FOR THE LEAST AMOUNT POSSIBLE.DONT GET ME WRONG IF I HAD A 1972 EL CAMINO WITH A 350 THEN THATS WHAT I WOULD BUILD,I WOULDNT REMOVE A 350 TO DROP IN A 305,AND THERE IS A TREND NOW WITH ALOT OF GUYS BUILDING 305'S JUST TO SEE IF THEY CAN COMPETE WITH THE 350 BECAUSE I SEE THEM AT THE TRACK ALL THE TIME AND A COUPLE OF THESE GUYS ARE REALLY DOING SOMETHING WITH THESE ENGINES. 300-400HP RANGE IS NOT A PROBLEM WITH MINOR WORK AND GOOD PLANNING,AND LIKE I SAID BEFORE THERE IS NOTHING BETTER THAN LETTING THE OTHER GUY KNOW HE JUST GOT SPANKED BY A 305.REALLY,I ONLY BUILD THEM IF THATS WHAT IT CAME WITH AND IN MY CASE IT ADDS TO THE VALUE OF THE VEHICLE BECAUSE IT IS ORIGINAL BUT EVEN THEN ITS NOT THAT IMPORTANT(I DONT THINK IN TWO YEARS I WILL HAVE A PROBLEM SELLING MY EL CAMINO WITH A 350 OR 305,BUT IT DOES ADD A LITTLE SOMETHING EXTRA KNOWING IT RUNS AS WELL WITH THE ORIGINAL ENGINE).SEND ME SOME INFO ON YOU BUILD AND I CAN TELL YOU WILL WORK WELL WITHOUT GOING TO EXTREMES.    HOFFY  

Please turn off the caps lock, it's a little unnecessary.  

Hoffy,

i tell you what reading what you write is like reading my thoughts, it is funny.  it feels good when someone you just smoked asks what you've got under the hood and you tell them it is a 305.  i love that.  i will respond in more depth about my build tomorrow right now it is 12:00 midnight and i was just working in the garage for about 36 hours straight with no sleep so i don't feel like typing much but yeah i definitely would like to hear some of your thought on what i have done, plan to do, and what you think i SHOULD do.  oh and personally i think the caps lock is cool.  it gives you your own personality in a place where there is none.  

by the way, what is shrouding valves?  

Valve shrouding refers to a restriction of airflow into the cylinder by some physical blockage. Usually the combustion chamber wall or cylinder wall.

Hemispherical chambers are designed almost completely eliminate valve shrouding but this chamber shape brings about other deficiencies such as poor thermal efficiency (dealing with surface to volume ratio), lack of mixture motion, and spark-plug usage/placement. Of course the mixture motion topic is highly debatable though...

High-end aftermarket heads for small and big block Chevys make the valve angles more shallow (23° compared to 18° for example, or 26° compared to 11° in the case of a big block Pro Stocker) in an attempt to reduce combustion chamber valve shrouding and also to build more compact and more efficient combustion chambers. Re-designed aftermarket small Chevy heads will also have canted valves (somewhat similiar to factory big Chevys) that attempt to direct the valve more towards the center of the cylinder at high lift to reduce valve shrouding.

Here is a photo that illustrates it well from an article by David Vizard entitled, "Porting Cylinder Heads - Port or Abort?" (featured in Popular Hot Rodding magazine)
Valve Shrouding Image

This article explains it more detail as well
"Cylinder Head Porting Basics" - by David Vizard

Don't say I never helped you...  

SHROUDING OF THE VALVE OCCURS WHEN THE CYLINDER BORE IS SMALL COMPARED TO THE SIZE OF THE VALES,COMBUSTION CHAMBER AND VAVLE LIFT.TRY TO PICTURE THIS IN YOUR HEAD,WHEN THE BORE IS 3.76" AND THE COMBUSTION CHAMBER WIDTH IS ABOUT THE SAME THE VALVES COME DOWN VERY CLOSE TO THE SIDE OF THE CYLINDER WALL AND CREATES TURBULENCE AND DEPENDING ON YOUR CAM SPECS(LARGE AMOUNTS OF LIFT)CAN HINDER THE FLOW DUE TO THE VALVE BEING AGAINST THE SIDE OF THE CYLINDER WALL.IMAGINE YOUR BLOWING THROUGH A STRAW BUT THEN SOMEONE PUTS A FINGER OVER THE END OF THE STAW OR CLOSE TO IT,THEN FLOW IS RESTRICTED OR INTURRUPTED.THIS IS WHY LARGE BORE ENGINES ARE A BETTER CHOICE BECAUSE WHEN THE VALVES ARE AT FULL LIFT THERE IS LITTLE TURBULENCE CREATED.THIS IS THE MAIN REASON THAT THE FORD 302 RUNS SO WELL FOR THE SMALL CUBIC INCHES IT DISPLACES(LARGE BORE, SHORT STROKE, AND THE VALVES ARE AWAY FROM THE CYLINDER WALL).I HAVE SEEN ON SOME 305'S AND OTHER SMALLER BORE ENGINES WITH HIGH LIFT CAMS THAT VALVE CAN COME INTO CONTACT WITH THE CYLINDER WALL.SOME OF THE OLD SCHOOL GUYS HAVE NOTCHED THE RIDGE IN THE TOP OF THE CYLINDER TO MAKE CLEARANCE FOR THIS PROBLEM.BUT DONT GET YOUR DIE GRINDER OUT JUST YET,BECAUSE VALVE SHROUDING AFFECTS MORE THAN THINK.I KNOW THAT YOU AND GIBTG HAVE YOUR DIFFERENCES BUT HE IS CORRECT ON SOME OF THE THINGS HE ADDRESSED.WHEN YOU INCOUNTER VALVE SHROUDING IT ALSO AFFECTS THE PERFORMANCE OF THE CAM,INTAKE,CARB,AND EXHAUST.YOU EVER HEARD THAT YOUR ONLY AS GOOD AS YOUR WEAKEST LINK,THATS THE CASE WITH THE 305.A GOOD EXAMPLE OF THIS IS YOU CANT RUN CYLINDER HEADS WITH VALVES LARGER THAN 1.94X1.6 OR THEY WILL HIT THE CYLINDER.BUT THIS IS ALSO THE REASON WHY NOS IS THE MOST POPULAR POWER ADDER FOR THE 305 BECAUSE TURBOS AND SUPERCHARGERS CANT RESPOND WELL WHEN THEY FACE RESTRICTIONS IN THE CYLINDER HEAD.WHAT YOU CAN DO IF YOU WANT TO SPEND THE MONEY ON THE 305 IS BEEF UP ROTATING ASSM,ADD SPLAYED FOUR BOLT CAPS AND INSTALL A MAIN GIRDLE TO TIE IT ALL TOGETHER BUT THIS DOES COST ALOT BUT WILL MAKE IT STRONG ENOUGH TO HANDLE LARGE AMOUNTS OF SPRAY.I PERSONALLY WOULD NOT SPEND THE TIME OR THE MONEY ON A 305(WITH THIS AMOUT OF HP) BUT IT IS YOU PROJECT AND YOU SHOULD DO WHAT YOU WANT SO DONT WORRY ABOUT WHAT OTHERS TELL YOU.BUT IF YOU DO DECIDE TO SPEND THE MONEY THEN SPEND IT WISELY ON PRODUCTS THAT WILL BE BENEFICAL TO THE OUTCOME OF YOUR PROJECT AND THAT YOU COULD USE LATER ON ANOTHER ENGINE IF YOU DECIDE TO.THE ONLY TIME A 305 WAS WELCOME TO ANY OF MY BUILDS IS WHEN IT DIDNT CALL FOR MORE THAN THE 500HP MARK(350 ON MOTOR AND 150 SHOT OF SPRAY).      HOFFY  

I definitely plan to "beef up" the rotating assembly.  i am going to go with a forged 3.75 crank forges rods and forged pistons.  i want to stroke th motor to a 335.  i am going to use some fast burn heads and i haven't really decided on the type of cam profile i want to go with but i know i want  a roller cam.  funny that you mentioned a stud girdle because my next purchase is either a stud girdle or a custom chip. i haven't decided which yet.

so anyway about what i have done so far.  not much as of yet, i just basically wanted to get the motor back running and in the car so i can drive it then i am going to do all of the interior and body work, then the suspension and then the drive train.  my budget is $15000,00 for this project adn right now i am at about $2500.00.  so i will try to list eveyr thing that i have done so far (or at least what i remember).

first i swapped the 1991 bottom for a 1985 h.o with flat top pistons, and put in a new high volume oil pump

then i rebuilt my 1991 heads with o.e. parts. I had the heads decked but i did not port which i wish i would have done but i was in a hurry at that point and i rushed them back onto the motor and that was a mistake - oh well.  I added 1.6 roller rockers as an after thought and some beautiful Chevrolet embossed tall valve covers polished aluminum foe astetics (or however you spell that).  

then i rebuilt the tbi e.o. again

i added a Erson hydraulic flat tappet cam 280/290 advertised duration; 214/224 @ .050 and .443/.465, and 112 separation.  pretty mild. and a new timing set.  this is one reason why i am not all that gun ho about machine shops. i let them pick my cam and this is what they got me. not really what i was hoping for but it will do a little.

i added a 3 inch cat back exhaust and Hedman shorty style hedders and a cat delete.

i rebuilt the ignition system with pertronix parts for a 45,000 volt output

a electric water pump

i removed the smog pump and all that b.s.

i added  160 degrees thermostat

4.10:1 motive gear rear end

b&m transmission rebuild and shift kit

b&m high output fuel pump 255 lph

NGK iridium plugs and i don't remember the brand but i got 8.8mm wires

and a set of BBK under drive pulleys

besides little various nick nacks i think this is all i have done to help the performance so far.

i have replaced some bushing and things like that.  but i think this is about were i am at.

late  

That is a very good point about the restriction in the induction tract of a supercharged engine...

Big boost numbers may look impressive but they are a measure of the heat created in the charge rather than a direct measurement on the added airflow's effectiveness. I don't care how many times I hear it, a supercharged engine DOES CARE about the induction system to a certain degree (maybe a little bit lesser than a naturally aspired engine). Just like with any other build, insane amounts of horsepower aren't going to come from small, stock'ish type valves and ports, even if you are pressurizing them.