Dave F

Thanks Bobby D. I didn't give that a real thought. Just assumed coming from Dart they would be ok.
Still, I should be ok as I'm using the Fel Pro Lock ring gasket and the additional two head bolts per side on the Dart Big M block.

I will bring it up for discussion with Dart however.

DAVE

KAAMA

I plan on running my 540's this next coming season just going to get them tuned up real good!

But you never know---those 598's might make an appearance some day. Thanks guys.

Dave F, glad to see that you went with the BIG M block. I think Turbo Jack is too!

Dave F

Kaama,

Thankyou for steering me in the right direction. Saved some money too.

Thanks
DAVE

Back4More

Canfield 350's man!

HyperBaja

LOL, 350ci heads!!!!!

I think thats the compression chamber on my 4.3!!!!

I cant imagine over 700 ft/lb!!!!

KAAMA

Okay, I'm going to stir the pot a little more here. I'll get a little more detailed. The heads I have now are Dart Pro-1 310cc aluminum heads w/2.30" intakes valves and 1.88" exhausts. Now then, by the way it sounds some from people that I have talked with that once ported, the Darts Pro-1's are pretty good. However right out of the box they aren't very good at all as JimV took them out of the box when I originally recieved them. Since then, he has fully ported the these same heads---this also included a chamber port. I have also been told by others that the Dart Pro-1's are NOT a very good head for supercharged applications because of their deck thickness. I don't need to worry about that because I plan to use the 598's in a naturally aspirated application anyway, so I should be fine there.

Here are the flow numbers from my heads from the full port:

Dart Pro-1 Aluminum 310cc @28" water on a "Super Flo" flow bench without a pipe on 4.50" cylinder.

Valve Lift CFM(Intake) CFM(Exhaust) % of Flow

.200" 149 130 87
.300" 225 171 76
.400" 295 206 68
.500" 348 256 73
.600" 380 286 75
.700" 394 300 76

I highly doubt I'll be using a cam much over .635" lift. I have discussed my heads with JimV and asked him how many CC's does he think they are now since he fully ported them? He said rough guess would be approximately 320cc's. Now then, I am wondering if I can use these heads on a 598" engine and perhaps spread the lobe seperation angle out on the cams to curb the torque numbers a little. Something like maybe 116* to 120* (lobe seps)even. I'm looking for anywhere from 700-725hp, but I'd like to keep the torque no higher than 700ft pounds if it is possible------but as I have said; that may not be possible or as easy as we think. 5400rpm is the RPM goal to run these engines with 5600rpm being the maximum.

cobra marty

Have you played on desktop dyno or similiar to get an idea for your hp and tq and rpm desires.

KAAMA

Yes, I have a "Desk Top Dyno" but it doesn't get into intake runner CC sizes. Some stuff I have compared from a real dyno sheet to a desk top dyno have been very accurate and other stuff not very close at all. But it is good for some reference points when making some other changes just to give you and idea of how much of a difference is between trying two different parts.

cobra marty

I'll play with my 'engine analysis' program. It is better than the desktop dyno. It allows for more input like head flow numbers, etc. What cam, intake manifold, exhaust?

KAAMA

Marty, I have the Stellings full length tubular headers. I think the primaries are something like 2-1/8" on the headers, with a 4.5" O.D. tailpipe (4.0" I.D. tailpipe), dry stack OPEN (no mufflers). I'll be using a single plane intake manifold something like a Dart or Brodix. For 598 cubes, I would probably use something like a 256*/260* or a 256*/262* or a 256*/264* @.050" hydraulic roller cam with something like .600"-.635" lift on 116*-120* lobes. Holley HP950 series carb. I would be using the longest rod possible with bore/stroke combination being 4.600"/4.500". Perhaps you can punch that in and see what it comes up with. Thanks

BTW Marty, I like a cam with slow/easy ramps speeds like the Crower cams have.