Double hump head performance vs Dart Pro I

Brutal64 · 11-07-2003, 10:19 AM

I'm currently running SHP double hump heads, 2.02/1.60, 64cc. I have begun to look at the Dart Pro I aluminum heads, 2.50/1.60, 64cc, 215cc intake runner. My questions are:
1. How do the Dart heads perform vs. the double hump heads?
2. Will I see a great enough performance increase to justify the cost?
3. Would the Dart iron heads work just as well as the aluminum?

Here is my engine configuration. The motor runs like a scared ape above 3k rpm but seems a bit low on bottom end torque.

355 CID
TRW 10:1 Flat tops
Summit Stage II rods
Gear driven Crane Cam 222/234 dur 469/492 lift
Crane 1.52 roller rockers
Mallory Comp 9000 dist
Edelbrock Victor Jr.
Speed Demon 650 MS
Dynomax headers
Flowmaster 40's 2.5" exhaust, H-pipe
4sp/3.55

Thanks

MrNuke · 11-07-2003, 10:53 AM

What are your current heads' runner size? if it is anywhere near 215cc that might be why you are a bit low on torque and low rpm power.
You only really need large runner cc's if you spin to high rpm or have a larger displacement engine (which a 355 is not).
The flow difference between the Dart Pro's and the Dart Iron Eagles (I have them myself) is about 15%-20% better flow rate on the Aluminum Pro's vs the Irons I think.

Brutal64 · 11-07-2003, 11:05 AM

Stock runner size is anywhere between 161-172CC's. So if I understand you going to a larger runner would actually hurt low end torque? Let me also say that I do have plans someday of stroking this out to a 383.

[Modified by Brutal64, 8:07 AM 11/7/2003]

gkull · 11-07-2003, 11:38 AM

Your better off buying the heads that might be a comprimise now if your planning on bigger ci later.

The out of the box Dart 215 cc's actually measured near 221 cc with the factory bowl blending and larger valve options. The Dart 227cc cnc is the best bang for the buck. They are said to flow 318/230 cfm. My ported 227 really run nice on my 383. But they are really recommended for 400+ ci small blocks running some higher rpm.

I also have a set of comp ported ARF210's which cost near the Darts and flow about 20 cfm less. The AFR's are really made for the smaller intake and header crowd. I was told by them that they support up to 1.4 hp per ci in the 400 - 434 class motors. The AFRs with options are $2200 and my Darts are just a bit more these days.

I have the optional 1.625 exhaust valves. If I did it over again I would have got 2.10/1.6

[Modified by gkull, 9:58 AM 11/7/2003]