Ok My budget motor is jumping up to a new set of aluminum heads, my credit card will love it. My question is which one on my 327, trick flow 23, or Elelbrock RPM. Quick review on my motor. 331, flat top TRW's, Cam is .488 both sides 292 intake and 300 exhaust on 106 center line, (.050 duration is 232 on both). Going to run an Elelbrock RPM Airgap and a 600 cfm. Later down the road a 383 will be instore.

With that size of cam I assume you are going more for mid and upper range performance in which case either head will work ok. I mention this because the TF 23 degree has a 195cc runner, which is a bit big for a 327, compared to the RPM edelbrock head which has a 170cc runner for more low rpm toque, throttle response, and midrange power. If you are going for more power up top I would say the 23 degree TF head, but if you want more of a daily driver type engine get the edelbrock heads. The trick flow head does have better flow numbers, but the velocity of the charge is undoubtedly slower.

You could also look into the twisted wedge TF head which costs around $1000. It has a 185cc runner I beleve... happy medium and they have higher flow numbers than either of the before mentioned pieces. And then again... there is always AFR for around $1200.

those twisted wedge heads are a nice piece. a very good middle of the road head.they are supose to have good swirl numbers too which should give you a little better fuel milage with the same power.

I just dug out my 67 Nova SS it has a 331 with the same parts as yours except less cam It has the twisted Trick Flow heads on it. I had forgotten how hard it runs. Even with 3.08s 2500 con. 350 turbo. If you are building a street car I would recommend the head. They can be a pain to set up. If you are carefull and follow their instructions you will have no problems.

What kind of problems are you looking at? Thats why I'm leaning towards the RPM heads.

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The twisted valves{it sort of looks like a BB} cause you to have to align the rockers on the valve stems. They give you instructions you must follow them completely or there will be problems but once you get it right it will stay there.



[This message has been edited by oger (edited 05-06-2001).]

I run the Twisted Wedge heads and they are very good. TFS claims a 190 cc intake runner, but mine fell in at 195. As others said, pay close attention to the installation instructions. You can get the instuctions from the site at www.trickflow.com (http://www.trickflow.com).

Those heads also respond very well to porting (if you have access to a flow bench). I added quite a bit of flow without really affecting low lift swirl.

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www.grapeaperacing.com (http://www.grapeaperacing.com)

One more question about the Trick Flow heads. The ad is Summit says you must use different length push rods. What all equiptment do you need besides the heads to get them set up?

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All you need is an adjustable pushrod, which are cheap. Check the rocker to valve stem contact point, if it's too close to the intake side adjust the pushrod shorter and try again (make it longer if it's too close to the exhaust side).

As the rocker goes through it's arc, it will move across the stem. There is be a point where there is not side motion and then it will start coming back toward where it started from. It starts on the intake side and travels toward the exhaust, once it reaches the 90* point (where the rocker pivot point and tip are 90* from the valve stem), it will start coming back toward the intake side again. You want that 90* point at about 65-75% of full lift. Once you get this, it will have more side motion at low-valve lifts and little at high lifts. You want it that way because at low lifts the spring force is at it's lowest and it's best to have th side motion then, where it will have less pressure on the guides. At high lifts, side motion will wear guides faster.

Another thing to look for is the amount of lift at peak piston speed. A 350 will have peak piston speed at 74.5* ATDC. As you change pusrod length you alter the lift curve slightly. For the best power, you want the highest lift at peak piston speed (highest flow demand). Adjust the pushrod and check lift at 74.58 ATDC and keep doing it untill you find the highest lift at that point. Once you do that, check the stem contact area, it will usualy right on, unles you have a very big cam.

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www.grapeaperacing.com (http://www.grapeaperacing.com)

I'm running the Trick Flow 23* heads on my 383. They are advertised in Summit as 195 cc. They do not have splayed valve angles like the big block - I think that was the older Trick Flow heads. I also think the 18* heads require the special valvetrain components and odd length pushrods. When installing my 23* heads, I read the instructions very carefully and nothing special was mentioned so I did nothing special. I've got 2000 miles on the motor and about 10, 1/4 mile passes with no problems. Hope I didn't miss anything . . .

GrapeApe, where do these heads like to be ported? Ehaust? Intake? Pockets? Valve guides? Just curious.

Eric68.
I have not yet done any work on the 23* heads yet, so I can't honestly say what what to do with them. I have worked on the Twisted Wedge heads (now called the G2 heads), but that wont help you. How do you like the 23* TFS heads? I seen some flow #'s on them and they looked like they flowed decent #'s, but were down on swirl a bit.

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www.grapeaperacing.com (http://www.grapeaperacing.com)