Big chamber vs small chamber

I have a question for all you hemi experts. What is the difference between a big combustion chamber motor, ie Veney, AJ/WAR and small chamber Brad 5 combo? I realize a big chamber combo takes a heavier piston to get the compression where it needs to be, but is there a difference in power, is one more forgiving than another as far as tune up, easier on parts, etc? In this scenario lets assume that overdrive is not limited, and running a screw blower so boost is not a problem either, so it would not be necessary to spin the motor past 8500-9000 rpm. Any thoughts?

 

The Brad 5&6 stuff makes more power because the ports are better, The smaller chamber makes a lighter recipicating assembly so you can spin it harder and not kill the bearings as bad.

 

Who says the ports are better?

 

You're right, I don't know about the WAR/AJ combo/heads. Only that the Brad 3's are also big chamber and not as good as 5's or 6's. And require the heavier piston as well.

 

There has got to be something out there since Veney's and Brad's (5/6) are at opposite ends of the scale (valve and pocket size wise), but both are part of winning combos. We have WAR stuff as well and they fall somewhere between those two.

Surely there is a way to run Veney sized valves with a Brad 5 type piston weight (600-650g)....
.....

 

What bore size is the 600-650 gram piston. Our 4.310 piston weighs 775 grams.I would just like to know for my own information. Thanks Mike

 

Not sure on the Brad 5 stuff as we are running WAR parts for now. Our 4.310 piston is 740g with the rings. I'm also curious how the total flow heads compare.

 

Gene, I have a set of billet Veneys with 160cc chambers I want to try. Are you recommending 50-55 degrees lead on those as a starting point also?
EDIT: Single Mag without alot of boost. Just trying to make 1500-1800 hp.

[ December 03, 2004, 01:53 AM: Message edited by: Maynard ]

 

on what fuel, NITRO???

 

If you put 50-55 degrees in with any head on alcohol, It won't make it off the jackstands.I had a customer accidentally put 40 degrees in, and blackened 4 mains, and 3 rod bearings.

 

Hey Mike how is the weather up there? Did you sell your sled? franny

 

Hey franny, Sold it, and another will be here within the week.

 

Mike" as a point of referance for myself and many others, what timing do you recommend for a large chamber engine? Is there a differance between a 450 vs. 526 cuin., roots vs. screw, single mag. vs. dual and dragster vs. funny car. Thanks STAN

 

Mike how is the weather looking any snow on the ground yet? So what did you 600 1000

 

Stan, There are many different ways to run each combination. if you want to talk about a particular combo, send me an e mail, or call me 518 864 5575. monday-friday 8:30-4:30

 

We got 2inches last night, but it is already melted. another 440 racer. But i will order another new 600 in the spring

 

correct me if I'm wrong if you run 27 on the lead with brad stage 5 heads your crank will live longer like 40 runs Vs big chamber heads with 40 to 48 on the lead 25 runs or less on the crank . joe

 

Who has big chamber heads and runs more than 32 degrees with an MSD 44?

 

OK I’ll take a crack at it, the taller piston dome might limit the flame travel. That is why Fathead stuff can run leaner or on less fuel volume, but the bigger chambered Hemi heads flow better, because of valve size, angle ??? The Fathead takes less timing because it needs less flame travel, but I think most combos even with the bigger chambered heads are in the low to mid 20s on the timing with a single MSD 44. Although some combos have certain mechanical advantages and disadvantages over the others as long as you have the latest stuff none are easier on parts in all areas. The biggest thing that makes them harder or easier on parts is the kind of tune up some run them with a lot of compression and fuel, but if you are off a little, the blower will be sitting in your lap. On the other side you can run low compression and a lot less fuel and it will haul ass as it melts its way down the track if the wick is long enough.