Hey guys. I have a set of Performer RPM heads on my .040 over 350 with about 10.3:1 CR. I also have a Crane Fireball hydraulic flat tappet cam, 224/234 duration at .050, .496/.520 lift and 114 lsa. I have a Comp Solid Roller XE280 cam, 242/248 duration, .576 lift and 110 lsa. Over my current combo, this cam is a roller step up and its solid. But I was thinking about upgrading my cylinder heads to Dart Iron 230cc ones, but am afraid they might be a bit too big for the 358. What do you guys think the motor would react like with these heads and the comp cam. Reason why I want 230 ccs is 'cause I am going to build a 406 short block by spring and want to use those heads on it. What do you guys think, go 215 cc runners maybe? I think Performer RPM is 170cc, not sure. Thanks guys!


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1981 Olds Delta 88 455/th400/3.23 posi

1988 Trans Am WS6, 355/T5/3.27 posi; RPM heads and Intake; Crane Fireball cam; Holley 750 carb; soon Comp RXE294H; th350 & 10" converter.

1994 Trans Am LT1/T56, no cat; Hooker CB; Hotch. SFC and STB; Ripper shifter; Poly mount; Lakewood LCA; K&N FIPK; Hypertech Airfoil; soon to port&polish MAF; Sprint springs & Bilstein shocks; GM Motive 4.10; Hypertech PowerTuner III

 

the 230's are recommended for 400+ cubes.. I have a set going on a 383, but it is 12.5 - 1, and running a 680 lift roller with spray, so we need the volume.. they would just kill your bottom end, and be pretty lazy below 4500 rpm.. depends what you want to live with until you do the 406... and I personally prefer the aluminum over the iron.. but that is my 2 cents worth!

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Texlurch - 68 Camaro (Just a little ol' LT1 with a Hot Cam, I SWEAR
" a little spray never hurt anyone, spank you very much!"
or the old standby:"I came here to race, not sell real estate. You ain't scared, is ya?"

 

it will work but depends on gearing and weight (the 2.08 valve is a little big). Go with a real short duration cam and small carb to keep velocity up.


Jan 2001 of chevy hiperf had a dyno test of a 350 with the comp XE268 cam and all five wp heads. 165, 180, 200, 215 and 230. The 200 made the most torque (about 1 ft/lb higher than the 215) and the 215 the most hp
The 230 had the second highest average torque and hp

[This message has been edited by gs400tx (edited June 16, 2002).]

 

don't the LS1 motors use 200-230cc runners (I forget the exact size)
yes, the runner shape is different to maximise velocity, but they are still darn big runners, considering the amount of torque the LS1 has everywhere...

maybe some of the traditional thought about runner size isn't as true as we thought?

 

the LS1 runner (about 200cc I think) is really tall and the fact that it comes to a point (near the Fuel injector), kind of keeps velocity high even with the size. ..

The LS1 is kind of in a class by itself. But,, your comments are valid, to an extent. The vortec head is also large by GM smallblock standards.. It also has a design that narrows towards the top to help velocity.