Midnyte81

Hello guys, its been a while. While I've been out, I've managed to come across a set of old complete Dart "High Port" aluminum heads. They are in great shape, have been reworked, 1.5/1.6 roller rockers, have a spring lift of .600, and contains all necessary hardware. They have 2.08/1.6 valves and have ported, polished, bowl blended, and surfaced. I have a 350 bored 4.060 and a decent bottom end. The guy I bought them from had 750+ hp N/A on a single plane, stroked 400. My goal is 400 at the flywheel. I don't mind 500, but I like the way my car looks without more than subframe connectors. the top end is a Comp Cams XE 268 and a dual plane Holley street Dominator intake and 650 Carb. Oh yes, the heads are 230 int. Finally, the only exhaust I'm running are Hooker Comp shortie headers with 3" collectors. They flow 289cfm int. Is this a little overkill , or am I setting myself up to get the XE274?

I'm primarily asking whether to keep or sell the heads. Second, whether buying the heads were worth it.

For safety, everything has been upgraded (to keep things short)

Right now, I have the famous 416's that came with the car (fyi: they are ported and polished) and just want something different, not to mention the added bonus of aluminum.

Sonix

iTrader: (1)

Did you dyno your car to show the 375hp? I've got ported 416's and a xe268 as well... hmmm.

230cc intake port, 289cfm heads? Uh yea, that's not matched to a compxe268. You need a full on race cam to use those heads. They're more suited to a big (BIG) inch small block like a 434, with a gigantic solid roller cam. They'd run pretty poor on your mild 350. You'd need something like 260* duration @.050 to get in the ballpark that the heads like to be in.

I'd try to sell the heads and get something a little closer to your goal. The car would be undriveable with those heads, no matter what cam you use.

Midnyte81

The dyno is 374.7, but i took the liberty of rounding off. the race gas didnt hurt either. So you're saying with those heads, I'll have no bottom end?

Midnyte81

I'm just making sure.....

So a 230cc (ported to 240) intake, high port aluminum cylinder head with 2.08/1.6 valves, 58cc combustion chamber, aluminum roller rockers (1.5/1.6 respectively) and a 0.477/ 0.won't make at least 400 hp on a 350 bored 4.060?
----------
Sorry, the cam is .477/.480.

camarolizard

that is way too much head for a street car,especially with your present gearingand combo

Sonix

iTrader: (1)

So you put your old 350 (with 416 heads) onto an engine dyno and it showed 375HP?
That's fantastic, gives me hope.

You'll probably get 400HP, but it'll be at a very high RPM, and you'll have a very narrow powerband. Your valves will float at higher RPM due to insufficient spring pressure, and hydraulic lifters - before you can make full use of the heads. You'll also have sad low end due to bad port velocity. Very narrow powerband.
I'd go with smaller heads, you'll just be disappointed with those.