Which Dart head?

[fastbuicks]

4.125 x 3.25 SB Chevy, 12-1, roller cam, 750cfm Holley, steel head rule. Fast 5/16's mile hi-bank oval. 2700# LM's. Which head do you guys recommend- Platimum200 or 215? Max rpm will be 7200-7500. The top five cars have this combo for 08-just can't confirm which head they have.

[lun40119]

My 215's stomped on the World 200's I had last year, from 5000-7000. Not saying that the dart 200's wouldn't do the same thing.......I don't know. I have links somewhere to the two dyno runs back to back..........you can HEAR the difference. Take care

Jake

[Trmnatr]

4.125 x 3.25 SB Chevy, 12-1, roller cam, 750cfm Holley, steel head rule. Fast 5/16's mile hi-bank oval. 2700# LM's. Which head do you guys recommend- Platimum200 or 215? Max rpm will be 7200-7500. The top five cars have this combo for 08-just can't confirm which head they have.

My 327 {3.25" stroke} uses the older Dart 215cc heads. you will be happy with the 215's as long as you have plenty of duration and tight lobe seperation

A cam no smaller than
268/276 @.050 on a 104°-106° lobe seperation

If you dont have any camshaft rules go with this grind
Crane 268/276 @.050" .670/.625 106°

[want-a-be]

I'd do the 215s... What cam are you running? How much dome do you have. How high is it? What Rod length are you running?

Don

[Awesome Bill]

The 200's will be more than enough for a 347 and only that rpm. Is it solid Roller? I would hope so.

[lun40119]

He said in the original post it was a roller cam

Jake

[fastbuicks]

It will be a roller. 268/276@.050 is a pretty wicked profile? We normally have been 255/260 at this track. Only on gas for 3 secs. Fast corner no brake. I my mind that profile would be for 8000-8500 rpm dry sump LW combo?

thanks for all inputs

[fastbuicks]

6.125 rod
Piston t.b.d. per head choice

[Trmnatr]

It will be a roller. 268/276@.050 is a pretty wicked profile? We normally have been 255/260 at this track. Only on gas for 3 secs. Fast corner no brake. I my mind that profile would be for 8000-8500 rpm dry sump LW combo?

thanks for all inputs

Now we have some more info

That cam in a Drag race 331cid engine which is the same stroke as you is good for 7,400-7,600rpm shifts and 7,500-7,800rpm past the lights with Dart 215's {older style, platinums are better}. These are wet sump engines

Now if you are a dry sump and with that long of a rod, I would look at the following

290/306 @.020" 260/268 @.050" .670/.625 106° , maybe even custom grind it with a 104° or so lobe center

If it was a drag race engine i have found 3-4 cams that work great Drag Racing::
1) 283/291 @.050" .680/.632 106°
2) 278/284 @.050" .684/.660 106°
3) 278/284 @.050" .670/.630 106°
4) 282/290 @.050" .670/.630 106°

In a drag race engine what the track has shown us is the RPM band is set by your heads. We have taken motors and put cams in with up to 23° more duration, didnt change much but the HP as the cars have 60' close to the same but pulled down the track so much better with the larger cams due to more hp

In drag racing i have found if your turning an engine 7,600+ put a big cam in it on a tight lobe seperation. This is with small blocks running Dart heads as thats all i use

[Awesome Bill]

We have run this combination more than once and I have never used anything over 260 on the intake and never over 266 @.050 on the exhaust and these are only in cases where the engine is wot on long tracks.

With duration any more than this, you will be left in the dust on the restart, especially black top. Your camshaft is not bad and you will find that your engine will not make any power over 7500 if you use a dyno.

Drag racing where you have a converter that usually is way to loose, responds to higher rpm just because it can't lock up down low and use valuable torque to get the dead stopped car threw the 60 ft fast enough to make a difference in et.

Cylinder heads, Intake manifolds, camshafts, and even rocker arms along with the proper carbs make a ton of difference. The package has to match, you just can't throw a larger intake runner on an engine and expect it to run just because it bigger. It usually goes slower. Read the thread about the s-10 going ½ slower!. This is usually the case.

To make good power where you need it has its own boundaries and you have to stay within or you will be following the leaders and then lapped in roundy racing. This is where everyone sees who is fast. Drag racers most of the time have never seen a dyno and usually in most cases don't say how big their stuff is so it covers their but when their cars are not as fast as others. e.t. racing proves nothing.

Class racing or index racing under 9 seconds really starts to show who is making power when the cars all have to weigh, a certain weight and run the particular parts the rules state. Most normal naturally aspirated engines make no power over 7000 to really see. If you don't believe me, get a dyno!

Now if you have really well prepared heads, intake etc, you can make some good power up top. But comp eliminator and pro stock are not your normal engines and it comes with a huge amount of responsibility, deep pockets and lots of work and maintenance. And those engines usually do not have the biggest ports, it is quite the opposite.

[jsup]

The 200's will be more than enough for a 347 and only that rpm. Is it solid Roller? I would hope so.

That's what I would think....