Why

What was the reasoning behind making the exhaust valve smaller in the BAE 6 head? Any ideas?

 

Possibly to get more valve to valve clearance on overlap to run a bigger intake valve or more intake duration. Hemi's have never had a problem scavenging exhaust as far as I know.

 

I am pretty sure Will is correct .

 

I could be wrong but, at the time IHRA had promod and was trying to protect wedge and cast heads with smaller valves in their rules. The heads were built to match those rules ?

Bob

 

Brad had a bunch of small valves he wanted to get rid of ?

 

This was my thinking as well but how does the smaller exhaust valve help with lower blower od? Also, I think the intake valve size was increased. What valve size do the Screw Blown alky guys run in the BAE V?

 

Ihra states 2.400 int and 1.900 ex valve diameter for blown pro mods and most others have adopted that ruling except maybe the outlaw classes .

 

IHRA is roots blown, I am curious about NHRA Screw Blown A/FC.

 

Brad heads

If I remember correctly, the Brad V heads were 2.425 int,1.950 exh. The VI heads are 2.400 and 1.900. The VI heads have an improved exhaust port and the intake ports are reshaped and no longer have the bronze pushrod tube inserts(don't miss changing them). The VI heads actually have "promod" stamped right into them. Just my $.02 Dan

 

My question is do they flow any more? Stevie Sanchez wants to modify our V's to a smaller exhaust,(says they'll flow more), but on the dyno at Fred Mandolini's we couldn't get enough exhaust to scavenge completely with the new overdrive(2.28) and the screw. This would make it blow up at 900 ft. going down the track. (Out of 12 runs, we've not kept the rubber band on it longer than 875 ft., good numbers to start and then it whacks the belt). We're going with the new Gates belt, two idlers and see then what happens. If anyone has flow figures you can share on the VI's, I'd like to see them before I modify my heads.