165cc to 180cc heads, is it worth it?
10-03-2004, 05:07 PM
#1
Racer
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165cc to 180cc heads, is it worth it?
I had my engine built a year ago from the stock 270, to around 370 or more. The disappointing thing is i have 165cc dart iron eagle heads. Great heads, but from what i understand, the runners are just too small. Would it be worth it to go to 180cc runners? Also, is there any difference between the dart iron eagle heads and the pro 1 heads when it comes to performance? Obviously the pro 1's are lighter, but what beyond that....? Tks
10-03-2004, 05:14 PM
#2
Race Director
What are the spec on you motor , compression ratio, cam, carb, intake, exhaust etc. Dart Pro 1 are racing heads that will benefit from large cam, high compression 
10-03-2004, 05:30 PM
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I don't know the most important thing of all, my cam. I'm hundreds of miles from my car, and the cam card is back home with my baby. Its not a huge cam though, i wanna say around 300 on the lift, but i'm not sure. I'm fairly decent its a crane powermax cam, thats about it. The car is a holley 650db. The intake i'll match to my heads. The pistons are forged trw flattop at 10.1. The block was bored .030 over, roller rockers (1.5?), and full exhaust work, including 2 3/4 pipes, flowmaster 40's, and an x-pipe. So what do you think?? Also, even if i stay with the iron eagles, what gain should i expect from 165cc w/72cc to 180cc with 67cc?
10-03-2004, 06:58 PM
#4
Race Director
Without the cam specs it's just a guess, the 180's will flow better at higher lifts and if the cam is not very big then there won't be much gain, if the cam is in th .475 + range there will be a difference but is the difference worth the price of the new heads ?
My suggestion is buy Sportsman II heads 200 cc a Comp Cams 270 H Magnum cam or 282S solid cam and RPM AIr Gap intake, that will wake your motor up
My suggestion is buy Sportsman II heads 200 cc a Comp Cams 270 H Magnum cam or 282S solid cam and RPM AIr Gap intake, that will wake your motor up
Last edited by MotorHead; 10-03-2004 at 07:13 PM.
10-04-2004, 09:17 PM
#5
Le Mans Master
My friend built a 12second 65 Nova 283 cu/in Chevy II block with SR torquers. The 305 series of SR torquers has a good combustion chamber shape and the heads will flow better than the LT-1/Z28 492 casting# heads with a good porting job (they are a little soft on the exhaust flow but still really good.) You could port your heads and pick-up some good power. My 12.28sec@117MPH 72 LT-1 has 175cc intake runners along with a fairly "big" cam (243@050 int/247@050 exh 560/540 lift Ultradyne solid cam) and works really well from 2200-7500 RPM. I made sure when I ported the heads that they didn't get turbulence that would cause the flow number to "back-up" and flow less at higher lifts. My flow numbers are not as good as many published numbers (I wonder if they calibrate their flow benches like my friend does?) but, the car runs well. I would not go over 180cc intake runners on a 350 cu/in motor. The 200cc sizes are OK for a 383 or larger motor but, I think they take too much bottom end away from a 350 motor. Many people I race against think I'm running a 383 BUT, my engine is a 355 cu/in (stock LT-1 crank, Manley 5.7 Sportsman rods, and Weisco 10:1 forger flat-top pistons.) People love to buy parts but, sometimes you are better to optimize your present combination and use the money for other areas of the car (tires?, suspension?)
10-04-2004, 09:37 PM
#6
Race Director
I only like to post what I know ( not suggesting you are not ) I made 296RWHP and 327RWT with the combo I suggested and basically the same bottom end ( 355ci), not lagging in the torque department too much
Last edited by MotorHead; 10-04-2004 at 09:44 PM.
10-05-2004, 08:22 AM
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Originally Posted by BrandonS
I don't know the most important thing of all, my cam.
As Solid LT1 said. Sometimes heads are overrated like when some say to do heads first.
Something you guys might find interesting:
Have seen tests w/ 270H where S/R Torquer 1.94 1.50 8.5 C/R &
Sportsman 2.02 1.60 9 C/R w/ ports matched & bowl porting were used.
Guess how much more HP the Sportsman made.
Only made 13 more HP or about what you would expect w/ 2.02 1.60 in the S/R. The tests were from RHS (Racing Head Service).
10-06-2004, 02:07 AM
#9
Le Mans Master
Originally Posted by MotorHead
I only like to post what I know ( not suggesting you are not ) I made 296RWHP and 327RWT with the combo I suggested and basically the same bottom end ( 355ci), not lagging in the torque department too much
10-06-2004, 12:58 PM
#11
Race Director
I didn't know this was a who's motor is badder thread or I would have posted my new motor's numbers. 
371 / 406 = .913 175cc
296 / 327 = .905 200cc
Not alot of difference it the hp to torque ratio.
371 / 406 = .913 175cc
296 / 327 = .905 200cc
Not alot of difference it the hp to torque ratio.
10-06-2004, 01:44 PM
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You guys have made up my mind!! I think i'll just stick with my 165's... lol. I've decided i'll get my gears in first, then just strap on a 75-100 plated shot. Its cheaper, less wear and tear in everyday driving, and will provide a hell of a charge at the track. Lol... now i'm gonna have 3 bottles in my car. A remote fire supression system, a fire extinquisher, and a 10lb nitrous bottle...... Speaking of all that, now i need to find out where i'm gonna fit it all!
