Dart head owners please come on it!
04-22-2008, 05:35 PM
#25
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Look at this thread, it suggests that stock heads have closer to a .150 drop and that trick flows, because of the valve angle, has an improved .155 drop.
http://forums.corvetteforum.com/show....php?t=1866372
We have a discrepency here, don't know who to believe.
Dart must have a published number somewhere. Let's say one wanted some aftermarket heads that flowed better than stock and one also wanted to run a particular size cam. Lets also say that one wanted to avoid potentially compromising the integrity of the piston by flycutting the piston. Ones only method of determining if a combo will work shouldn't be by actually buying the parts and testing. If one then finds that the parts combo won't work one is, at best, out some significant $. Either the heads or cam needs to go or one can A)use ones novice ability and drill a large bore hole in ones piston by taking a stab at fly cutting his piston or B)Get a group of buddies to push ones car, which is currently all over the garage floor, to a competent engine builder 50miles away who can do it for one. Then one finds out 200 miles down the road that some of the aluminum shavings found thier way into the bearings and the motor blows up or one runs a little to lean on the high end and the weak cast pistons manages to burn a hole in the fresh made weak spot in the piston.
What the heck did dart do to reduce the valve drop on thier heads? Did they reduce the combustion chamber size by moving the whole valve assembly closer to the piston...brilliant!
04-22-2008, 05:40 PM
#26
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You are a very knowledgable LSX source. I'll test but I don't want to find bad news. If I went with any other head manufacturer I would have been OK....darn these Darts. 
They seem to be good heads but I guess you get what you pay for.
04-22-2008, 07:14 PM
#27
Likely you are OK, but there is so many variables. The cam could be off or ground incorrectly so it may not be the heads. Since you have the time, peace of mind. Its one of those things that when it goes wrong you'll say, "damn, wish I had checked that."
04-22-2008, 11:12 PM
#28
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I have complete faith in Comp Cams. Hehe, I saw that post on corvette forum where the lobe on the comp cam actually extended past the bearing journal (or what ever its called). Needless to say mine went in just fine with a little coaxing from my rubber mallet.
04-23-2008, 12:48 AM
#29
I don't have any tools to accurately measure anything, that's why I rely on gurus like yourself
Look at this thread, it suggests that stock heads have closer to a .150 drop and that trick flows, because of the valve angle, has an improved .155 drop.
http://forums.corvetteforum.com/show....php?t=1866372
We have a discrepency here, don't know who to believe. Dart must have a published number somewhere.
Let's say one wanted some aftermarket heads that flowed better than stock and one also wanted to run a particular size cam. Lets also say that one wanted to avoid potentially compromising the integrity of the piston by flycutting the piston. Ones only method of determining if a combo will work shouldn't be by actually buying the parts and testing. If one then finds that the parts combo won't work one is, at best, out some significant $. Either the heads or cam needs to go or one can A)use ones novice ability and drill a large bore hole in ones piston by taking a stab at fly cutting his piston or B)Get a group of buddies to push ones car, which is currently all over the garage floor, to a competent engine builder 50miles away who can do it for one. Then one finds out 200 miles down the road that some of the aluminum shavings found thier way into the bearings and the motor blows up or one runs a little to lean on the high end and the weak cast pistons manages to burn a hole in the fresh made weak spot in the piston.
What the heck did dart do to reduce the valve drop on thier heads? Did they reduce the combustion chamber size by moving the whole valve assembly closer to the piston...brilliant!
Look at this thread, it suggests that stock heads have closer to a .150 drop and that trick flows, because of the valve angle, has an improved .155 drop.
http://forums.corvetteforum.com/show....php?t=1866372
We have a discrepency here, don't know who to believe.
Dart must have a published number somewhere. Let's say one wanted some aftermarket heads that flowed better than stock and one also wanted to run a particular size cam. Lets also say that one wanted to avoid potentially compromising the integrity of the piston by flycutting the piston. Ones only method of determining if a combo will work shouldn't be by actually buying the parts and testing. If one then finds that the parts combo won't work one is, at best, out some significant $. Either the heads or cam needs to go or one can A)use ones novice ability and drill a large bore hole in ones piston by taking a stab at fly cutting his piston or B)Get a group of buddies to push ones car, which is currently all over the garage floor, to a competent engine builder 50miles away who can do it for one. Then one finds out 200 miles down the road that some of the aluminum shavings found thier way into the bearings and the motor blows up or one runs a little to lean on the high end and the weak cast pistons manages to burn a hole in the fresh made weak spot in the piston.
What the heck did dart do to reduce the valve drop on thier heads? Did they reduce the combustion chamber size by moving the whole valve assembly closer to the piston...brilliant!
One aspect you need to consider here is combustion chamber and intake valve size. The Darts are 62cc's out of the box, have a 2.02" intake valve and maintain similar valve drop characteristics to a 241. The net is you get 5cc smaller chambers, a better flowing head, and a slightly larger intake valve. You can't knock Dart for anything here, it's the nature of modifying a car.
I'll correct the post above, sorry for the confusion.
Last edited by 405HP_Z06; 04-23-2008 at 12:54 AM.
04-23-2008, 11:57 AM
#30
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I just reciently installed the dart 225 heads on mine and am running a tsp ms3 237/242 cam and it runs well. Had the cam before with the stock heads and had trouble getting the car to idle. Now the car idols alot smoother and doesnt try to stall like before. Well worth my investment.
04-23-2008, 12:39 PM
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I looked back at my notes and I made a mistake on the valve drop that I stated earlier. I tested a set of used 241's and I measured .153" intake and .163" exhaust. I've never measured a new set, but I'm sure there would be some variation between heads. This being the case, one can estimate whether or not a cam SHOULD fit but, IMHO, you need to check it to be sure.
One aspect you need to consider here is combustion chamber and intake valve size. The Darts are 62cc's out of the box, have a 2.02" intake valve and maintain similar valve drop characteristics to a 241. The net is you get 5cc smaller chambers, a better flowing head, and a slightly larger intake valve. You can't knock Dart for anything here, it's the nature of modifying a car.
I'll correct the post above, sorry for the confusion.
One aspect you need to consider here is combustion chamber and intake valve size. The Darts are 62cc's out of the box, have a 2.02" intake valve and maintain similar valve drop characteristics to a 241. The net is you get 5cc smaller chambers, a better flowing head, and a slightly larger intake valve. You can't knock Dart for anything here, it's the nature of modifying a car.
I'll correct the post above, sorry for the confusion.
This supports my "eyeball" measurements. Side by side it certainly appears that the Dart heads have similar valve drop characteristics and location to the stock heads. The valves are noticebly larger and, thus, would have less overrall drop than a stock head.
I agree that you should be able to determine what will work before purchasing the products but that isn't a substitute for phyisically verifying the set up.
For the price Darts can't be beat, as you described above. However, I wish Dart would have included the valve drop specs in the published spec info of these heads.
04-23-2008, 12:40 PM
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I just reciently installed the dart 225 heads on mine and am running a tsp ms3 237/242 cam and it runs well. Had the cam before with the stock heads and had trouble getting the car to idle. Now the car idols alot smoother and doesnt try to stall like before. Well worth my investment.
Now that is a big cam