gm cast iron intake please help

in my class of racing we have to run a cast iron stock intake manifold we are not aloud to modify them in any way... does anyone have an idea witch ones flow best??? for high rpm .... no marine propane or fuel injection manifolds thank for what help anyone can give  

You have'nt stated track size, but no cast iron intake will flow high numbers, best bet is to gear the car with same MEP camshaft to run with that cast iron intake. Most cam makers have a good flow numbers and cam grind to meet your needs. Maybe try a cast iron intake from camaro early quad carb. Also will your rules allow carb. spacer??? 1' + ?? You could try Berzenskis in Milwaukee, Wi. they do under cover work, and have higher flow numbers that would more suit you.  

Also try and stick with the same flange as your carb. (ie.. square-bore to square-bore,ect). Running an adapter only works good for Johny Cash. Try also to find one without an EGR valve, your not racing the smog police!  
"Remember when sex was safe and racing was dangerous?"

we run in a class that has to have cast iron intakes we use a gm marine intake with a 2 barrel carb that flows680 to 730  and we dont have any problems  

Brezinsky seems to be a favorite around here.  
"Remember when sex was safe and racing was dangerous?"

My son runs in a like class. We use an intake from a 73 Impala with a cast number 346260. You can look that up on internet. Google chevy intake cast numbers. But that intake is higher than most, and flow results are quit good at around 6000 rpm. Of course you can always do a little hidden work to it as well. Hint Hint and is hard to find.  

canadan intakes of sb 400 motors 70-73 impalas are what i have told to use?  

What do you mean by little hidden work?  
Auto Racing Tickets

RUN EARLY LIKE PRE 73 400 OR TRUCK OR SOME CHOICE 350'S HAD THESE BIG 2BBL INTAKES U CAN TELL JUST BY LOOKIN AT THE RUNNERS THEY ARE HUGE COMPARED TO REG 2BBL INTAKE . GET PRE EGR AND RUN ROCHESTER 2BBL 500 CFM CARM BUT HERE IS A QUICK CHECK TAKE A 5/8 WRENCH AND IF IT DOES NOT FIT OVER THE VENTURY U DONT WONT IT IF IT DOES U SCORED I RUN THIS ON A 355 WITH VORTEC HEADS 10/1 COMP AND A ISKY CIRCLE TRACK CAM WITH 74 JETS . LET ME TELL U IT *** RETARDED ABOUT 360 HORSE THOSE INTAKES FLOW AND I DID NOT TOUCH MINE. FIND IT RUN IT WIN.  

I am running in similar class.  Just started racing. 7 races. Going to junk yard.  

You leave out the most important piece of info. What if any are the rules regarding carbs??
Worrying about intake flow is pointless if you are restricted by the carb,if you can't use at least 500cfm no reason to look for large intakes,in fact too large may be a problem.
Another big issue is cubic inches??
If at least 350 CI and 500 cfm carb   I'd be looking for the early 70's z/28 manifolds  also found in some SS model of other nameplates
just my 2 cents  
Actually I watched it more than once,back when it was worth watching!!!

Ezrider714....very true on a lot of accounts. As I stated matching will do more good than searching for the straight largest.  
"Remember when sex was safe and racing was dangerous?"