I just got this program and I'm learning the ins and out of it. In the head selection It gives 4 types of heads with differant valves. I'm running cast iron 96.4 cc oval port closed chamber heads with larger intake valve 2.19 & 1.7. Which head selection should I use? A few choices are obvious not to use. What would be close to my set up?

Low Performance,
Wedge,
Canted,
4-valve,

The BB heads have canted valves. If you have flow #'s, you can enter them directly. Or, you can find #'s on similar heads and use them to start with.

Go to Chevy Hiperformance for flow data on stock heads. In your case, I would use the stock 049 head (open chamber head) flow data on the intake side. Use the stock closed chamber flow data for the exhaust. I looked for similiar data also, and could not find any for a stock closed chamber head with a bigger intake valve. Short of flow testing, this is the best you can do. I would doubt, though, that the larger 2.19 intakes would provide more than 5 - 7% flow increase over stock.

I think his question is related to how DDyno factors in valve size, EVEN after you have entered flow numbers. I have no good answer for this, except to say that he is correct in observing the change in hp with all other things remaining the same except for a larger valve.

Thanks guys. That puts me around 475-500 HP and 490lbs of tourqe. If this thing is right.

Try this site they have flowed quite a few heads and put them in a usable format.
http://www.prestage.com/

great link, thanks.

I can tell you from real world experience. The only way to get 500HP from an oval port 396 is with 11 to 12/1 comp and a big solid roller cam that is nearly non-streetable. You can get 450HP with no trouble, but 500 HP is going to be somewhat radical. You really have to pay attention to the head flow numbers to get accurate results.

Your probably right but, look it is a 414 not a 396.

My 414 laid down 350 on a chassis dyno...which is realistically about 425-450 HP at the flywheel, depending on how much percentage drive train loss you want to calculate in. The buildup is in my signature.

As stated, you simply aren't going to get those kind of numbers unless you're running higher compression, or some other more radical method of squeezing umph out of it...it's physics, plain and simple...Desk Top Dyno isn't real world. I bought DT2000 in 2000 and threw it away.

The best way to use DD2000 is to establish a baseline for comparison and calibration. Set up several engine combinations based on published dyno results, using real airflow and cam profiles for the engines that you are setting up. Pay attentino to details [compression, carb size, pressure drop, etc.] By doing so, you will learn the characteristics of the program and can then use this experience to validate your own simulations. For practicality sake, 425 - 450 HP from a 414CI BBC is still a potent engine. No matter how you look at it, it takes a lot of compression,cam and cylinder head flow to make more than 1 HP / CI. Closed chamber oval ports [unless professionally modified-extensively] don't flow well enough to support big HP.

Sounds like good advice to me. Sean, it sounds like our set ups are just about the same. Thanks for the chassi dyno numbers.

The one thing it doesn't say in that write-up is that I went with Manley 2.19/1.88 valves. I would suggest this if you're going to run an oval port GM head. These stock heads flow pretty damned good, as is, and a larger valve really wakes them up.

There just isn't much you can do with these smaller cubed BBC's without going to more radical methods (compression, forced induction, roller cam). I pretty much hit the ceiling on my combo. There's no replacement for displacement!