Which Head?

Hi,
we're doing a twin 88mm turbo hemi on alky and I was wondering if there's a major difference between the BAE 5, 6 & 8? It'll be a short stroke, big bore combo. Looking at other people running the same type of combo, there seems to be all of them run with some degree of success. I was wondering if there's anyone here that knows of a reason to run one head over the other.
thanks,
shawn

 

brad 8 is a big valve TAD/TAFC head 5 can be either 6 and 7 are smaller valve pro mod heads currently the valve size on a nhra turbo hemi isnt restricted like a blower car is so its an easy choice our preferred weapon in pir twin turbo hemi is NRE for the valve spring oilers good flow characteristics but we use inconell exhaust valves in them whats your bore /stroke we are 4150 with a big bore block and custom thick wall liners
bs3 rossler /pro torque after 2 years on a clutch

 

We're doing 3.750 stroke 4.500 bore, BS3, Rossler. So pretty similar combo. We want to run some outlaw 10.5 stuff and maybe AA/AT in Comp. I've seen the NRE heads, but don't really know a lot about them. At $10.5k per set it's probably a little more than we're going to spend to start when you can find a good set of used BAE heads for half. Or less, lol. So there's no major port differences in the 8's from the rest other than valve size?
shawn

 

Bae

I just got a bae recently and the biggest hp spread Estimate i got between all the bae heads was 100 hp. Some guys were as low as 50. That might be a lot to a legal combo but doesn't mean much to a c rotor. I know of bae 6s that run 350s in adrl.
If I was building a turbo combo I'd put all my effort into power management and when it was fast worry about massaging more power out of it.

 

Thanks Mike and Overkill. I own a machine shop and do cylinder heads, so I do know something about head advancements and technology but the alky hemi stuff is a little out of my wheelhouse. I've talked to people who told me the same thing Overkill. I also know one of the fastest cars in the country has 5's on it. I really don't want to sound like I'm asking a question and then telling someone why their wrong (one of my huge pet peeves). What I was more looking for is the actual difference in the casting, finished port design itself or on track performance difference. Like Mike stated, I've been told the NRE is at the front of the pack currently, but why? How much was really gained? Thanks for the info!
shawn

 

I was the first guy in europe to run the NRE head,
les Davenport back to back dynoed them against 6's and found 70 hp in a nhra legal blower car....
Les's dyno is honnest not massaged numbers for customers benifit like some i could name

i think at 4.500 your liners will be too thin as your concidering brad heads i know you have stock bore centres
we have run this deal for two years and our development is downsising the bores and fitting the thickest wall liners we can get in the block, you dont need such a short stroke as the effective rpm range is lower than a blower car and a 4.150 crank will go way over 10,000 with no probs if everything else is right, if you were on smaller turbos then maybe but not with these things..... we do this for piston seal gains.......just my 5 pence...(im british )

 

Keep in mind that the 7X and 8X take a different header.