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Author Topic:   RPM limit on heads
ssanto06
unregistered
posted February 02, 2004 11:21 AM           
I'm building hobby/pure stock motor to run on a 3/8 dirt track next year. The rules say a max of 0.410 or 0.450 lift hydraulic cam.

I have a set of 882's... stock rebuild (stock valves, springs).

I can run any 2 or 4 barrel carb, stock cast iron intake. Oh... and no holley carbs. What kind of carb would fit best?

What kind of RPM would these heads top out at? What if I put in better springs (Z28)?

I've already got the heads and thats all I've got... so I'm kinda building the engine around them

Thanks,
Sal


racer17j
Member
posted February 02, 2004 12:01 PM
with good springs they wil flow all your going to throw at them with a stock intake and carb and that small or a cam . i run them the first year i had 480 cam stock springs and 2 brl rochester would turn 5800 no more changed too z28 springs now it turns 6800. carb wise i have never ran a quadrajet on a race car but i have had nothing but trouble with them on my truck after 3 or them i took it off finaly and put a my spare 2 brl rochester on it and haven't had a lick of carb trouble since.but my choice would be a motorcraft 2 brl if you don't have to stick with a gm carb we used to run those way back when before we went to a gm on gm rule


ssanto06
unregistered
posted February 02, 2004 12:41 PM           
So do you think it would be worth it to put the z28 springs... ?

You're saying that the 882's will still flow good with stock intake and cam at 6000-6500.

thanks,
Sal


Raz_900
Member
posted February 02, 2004 01:56 PM
They'll do ok flow wise with the other limits you have. Although, the big chambers will hurt compression. The stock valves and springs really should be pitched. A decent set of undercut valves can get you a couple CFM in flow and the stock springs can float as early as 5200 rpm. K-motion makes a decent set of springs for $45. I think the PN is 700 or something like that.



racer17j
Member
posted February 02, 2004 05:19 PM
ya 6500 woulf be no prob thats what mine runs with just z springs are the only thing i have done to um


LUBEGUY07
Member
posted February 02, 2004 06:24 PM
with that cam limit run vortec heads and intake the work very well with that low lift of cam


towmandan
Member
posted February 02, 2004 06:42 PM
I would definately change the springs and as for the carb I wouldnt try to run a 2brl against 4brls talk to KP on here about a race prep Qjet but I wouldnt run a stock Qjet there are a few mods that need to be done for dirt trackin........Towman


24s52
Member
posted February 03, 2004 08:06 AM
i've run my rochester against 4 brls on a 14 and 3/8 they still didn't have much for me but that could have been because i has a 400 and they had 305's and 307's lol


77k
Member
posted February 03, 2004 11:36 PM
A lot of people don't know that the back butterfly's on a Q-jets are adjustable,good thing to do on playday.


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