Thanks for the explanation Martin! In my head, I see it that a lobe with .700" lift would have a faster ramp than the same lobe with .600" lift, since the lifter has to climb the additional .100". So to do that, you just pair it with a mild cam lobe and good springs. How often do the .700" valve springs last and with that much lift, is the valve train a bit noisier?

 

That is not always the case.

Think about it like this.

You have two sports cars. One goes 200mph top speed. The other goes 225mph top speed. The one that goes 200mph reaches 200mph in 10 seconds. The other that goes 225mph reaches 225mph in 25 seconds.

As you can see the car that has a 200mph top speed has a faster acceleration rate even though the car that is able to reach 225mph top speed, still accelerates slower at 9mph per second where the other 200mph car travels 10mph per second.

This is a great comparison to compare one lobe that has .700" valve lift versus another lobe with .600" valve lift.

 

I went to order these heads and they have an estimated ship date of 7/1/13.... I will give them a call tomorrow but did they have them in stock when you ordered?

 

Sounds impressive for 255cc.

 

Summit doesn't have the trickflow head I want so I might go with the bare castings. Does anyone know if you can use stock ls3 intake and exhaust valves in these heads? I know the heads are 12 degree and the stock ls3 heads are 15 degree. Does that mean I can only use a 12 degree valve. Sorry for the dumb questions.

 

I h8ghly d9ubt st9ck valves will work. Maybe with some work, but stock to drop right in im gonna say no.

Possible, but not probable.

 

These heads are so new it is impossible to find any info on them. I can't find how much the valves weight or anything. They are the same size as the hollow stem ls3 valves but that is the info on them.

 

I can just buy the 255 heads that come with the stiffer spring but I think it might be too much spring for my application. What do you guys recommend:

1.300" o.d. dual spring (TFS-16904-16)
132 lbs. @ 1.850" installed height
372 lbs. @ 1.200" open
370 lbs. per inch rate
.650" max. valve lift

OR

1.300" o.d. dual spring (TFS-16306-16)
145 lbs. @ 1.850" installed height
438 lbs. @ 1.200" open
448 lbs. per inch rate
.650" max. valve lift


I have a comp cam with the HUC lobes, LS7 lifters, and not sure what valves come with the TFS heads.

 

Man my computer got some virus like Micheal Douglas from eating Pu@$y, LoL. AKA: I have to go to the library. I've looked at Pac springs for mine, but decided to sit on them and I also have to buy Valve's I will be looking at either Si valves or Ferrea hollow stem valves, I got my Holley 4500 TB in lay-away today.Cost: 600 bucks, total owed 300 bucks hope to have it by next week. Guy's I'll try to catch up once a week, Cause 250 bucks, to have my computer fixed is my 4500 TB on my intake Minus wilson 4500 adapter. Holla Back.I also gave some one on here the bare head part # cause Summit didn't even Know it.... Real ****. They charge $1050 for a bare head when if your a dealer the real Cost is 918 plus tax. I had to pay really 975 per head bare cause I am really good friends with the shop owner. I've known him since I was a kid. He has to make a profit also. Check you next week.

 

Yea I can buy them for 918 bare.. I got an email back from TrickFlow and they said the stock LS3 valves are too short for there head. Didn't say the length of there valves though. The intake valve is 113g and exhaust is 95g. Those seem pretty heavy compared to the 89g hollow stem ls3 valve. The cam that is currently in my truck has HUC lobes so it shouldn't have a problem with the extra weight. Should I go with the stiffer spring with the added weight or will it just rob power? Not sure if the softer springs will cause valve float. Help would be appreciated!

 

What rockers are you using oakley?

 

Yella Terra 1.8's is what I will be adding with the head swap.

 

Heavy valve, heavy and failure prone rocker. Sounds like a recipe for a rock solid/reliable build.

 

Thanks Jimbo for your arrogant comment! You come of as a helpful/knowledgeable person.

 

Small port being what ? I still think the mast heads are top dog.

 

They come with a 255cc intake port and 87cc exhaust port. The trickflow heads have better flow numbers than the MAST with the same valve sizes. It would be nice to see a comparison dyno sheet between the two but I think the TFS heads will take the cake.

 

This is where you are not reading the fine print the flow numbers are not the same the mast heads are flowed on a 4.0 bore and trickflows are flowed on a 4.065 it makes a difference. Just giving you the facts.

 

.... Actually MAST flow numbers are on a 4.070" bore. So the TFS head outflowed the MAST on a smaller bore by quite a margin. This thread is not about the MAST heads. Thanks though

strait from there site:
http://www.mastmotorsports.com/2010/...sembled&id=362

 

I was able to find the intake/exhaust valve length on the Trick Flow website. There is a .pdf installation doc available. It lists the lengths at 132.08mm. There is no information on weight.

Here is the link to the document:

http://static.trickflow.com/global/i.../tfs-dp-22.pdf

 

Good find! Looks like they are close to the same length as the LS7 valves.