1992 5.0 build up

[Robocop]

I appreciate the input LeeH and I really know nothing about cams anyway. I did not even know until recently that the TFS kit came with a cam. I am still learning a few basics and plan to talk to the machine work guys and determine the way tp proceed. I originally wanted to have my heads and pistons figured out in order to figure the compression ratio for a mildly boosted set up. I am basically at the mercy of others here as I do not know the tech stuff.

I think it would be best to design my cam around my motor and what goal I am looking for. I found out that the TFS kit has a cam and I wanted to run the specs past the machinist however I thought the whole purpose of a kit was that all the parts were proven to work well together. I wonder if I can buy the kit minus the cam and have a custom ground one done later?

I have copied the specs on both stage 1 and 2 cams that were given to me earlier in this thread. This will help me make a decision a little later. I am going to try and go to Howtons this week and start working on some prices for the forged stroker parts. When I get prices I will let you all know and I can go from there. I think it was posted that the heads in the kit have a 61cc chamber. What type of pistons should I use with these heads in order to be able to run a mild amount of boost....maybe 8-10 lbs. Will the pistons have to have that weird fly cut stuff? I really do not know what that means however I read that for some heads it has to be done.

[1sicklx]

Originally Posted by Robocop

however I thought the whole purpose of a kit was that all the parts were proven to work well together.

that is the idea behind both the TFS and Holley kits

[Italian LX]

Originally Posted by Robocop

Will the pistons have to have that weird fly cut stuff? I really do not know what that means however I read that for some heads it has to be done.

Fly cutting is refering to the half-mood shaped valve reliefs in the top of the pistons. This gives the valves a little extra clearance when they are down and the piston is up. The amount of valve relief will be directly related to the shape of the piston top and the specs of the cam.

[NightHawk756]

Originally Posted by The Sickness

that is the idea behind both the TFS and Holley kits

As far as the pistons go, I suggest forged. As well as the rods. If you have to, I think you'll be fine with a cast crank. And when you buy the forged pistons, just buy them already fly-cut for twisted wedge heads. That way you have nothing to worry about. Especially since your undecided on what cam to use. That is, unless you want to go with a dish top piston for lower compression if you want to run high boost later. But you'll be fine if you only want to run 8-10lbs. with the compression you'll get from flat tops.

[LeeH]

Originally Posted by The Sickness

that is the idea behind both the TFS and Holley kits

Problem is the Holley kit is designed to work on a 9:1 302ci engine, The early cam that came with the Systemax II was leaps and bounds better than the current one. Holley made many changes trying to address the valve guide issues and the cam was one of the first major changes to the kit. The TFS kits are okay but again are designed with a stock short block in mind, The #2 and 3 cams are of course not meant for use on a stock short block but they are designed around a hypothetical combo. Just understand in your selection of parts that the TFS TW heads intake flow stalls at and above .550 lift, Nothing except alot of bowl and chamber work will change this. Keep this in mind when selecting a cam if you dont go custom, The good low and mid lift numbers on the TFS TW heads are what makes them soo good for a street car.

The way I would build a N/A 331 for a daily driver:
10.5:1 compression(JE/SRP, Probe, Ross etc.)
Cast crank(stock block will fail before a good cast crank will)Eagle or Scat
I beam rods(Lighter rotating mass)Scat Cap Screw rods
TFS TW, AFR185, 192 Canfeild
Edelbrock Perf RPM2, Holley Systemax II(I dont like the Holley's quality)
Custom grind or OTS Comp XE274HR

If I was planning on 8-10psi the above would only change in compression to 8.5-9:1 and the Cam would still be a custom or for OTS cams the AFM B4 is a pretty good cam which is nearly identicle to the TFS #2. Another good intake with boost or more cubes is the TFS "R".

[Robocop]

OK so far I believe I have 2 choices if I go with the TFS upper combo and that is stage one or stage 2 with either the Track Heat or Street Heat set up.
If I read correct the cams offered are......

Stage One:
Lift: .499 Intake/.510 Exhaust
Duration: .275 Intake/.279 Exhaust (Gross duration)
.221 Intake/.225 Exhaust (.50 duration)

Stage Two:
Lift: .542 Intake/ .563 Exhaust
Duration: .289 Intake/ .294 Exhaust (Gross duration)
.224 Intake/ .232 Exhaust (.50 duration)

I think I will go ahead with the flat tops cut for the TFS heads with the plan of using a mild amount of boost. I do not know what the above numbers mean however using the 2 cams above what would be the differences of both. Is one cam set up for more low end and the other more mid range?

Also LeeH what does it mean when you say the intake flow stalls above a certain lift? Does the car actually stumble or fall flat losing power? I am going to Howtons Monday and need to tell him what to get prices on for me. Once I have that I will use that as a base and see where else I can try to find a stroker Kit. I also have to call Pro Line in Woodstock Ga. Those guys seemed to really know what I was looking for however I did not get to talk to them for long. I said I was shopping around and they said to call back when I knew exactly what I wanted.

One more thing.....
Would it be the same to start with a higher compression motor and use no boost. Lets say that I went with 10.5:1 N/A would it be just as good to go lower like maybe 8.5:1 with a little boost ? Doesnt a supercharger simply increase the compression in the chamber? It seems that a N/A motor could do almost as well by simply starting out with a higher compression ratio in the first place.

Sorry so long however I have never tried to figure out the finer details of a motor. I thought I knew the basics and found out that I do not know much of anything at all.

[Italian LX]

Originally Posted by Robocop

Also LeeH what does it mean when you say the intake flow stalls above a certain lift?

He means that the flow doesn't increase significantly even as the valve continues to open further. You can see it in this flow chart on their website:

http://www.trickflow.com/product/for...ed_airflow.asp

However, you can someone port the heads to help that problem if you ever decide you want to untilize the heads more in the future. Here are some flow charts from TEA:

http://www.totalengineairflow.com/pr...ordhead/tfstw/

[Italian LX]

Originally Posted by Robocop

One more thing.....
Would it be the same to start with a higher compression motor and use no boost. Lets say that I went with 10.5:1 N/A would it be just as good to go lower like maybe 8.5:1 with a little boost ? Doesnt a supercharger simply increase the compression in the chamber? It seems that a N/A motor could do almost as well by simply starting out with a higher compression ratio in the first place.

You're statement is basically true, but there is a little more to it -- there are pros and cons to both set-ups. Things like blowers add heat and make more work for the motor... but they also give you the ability to increase power with only a pulley change. An N/A motor will cost more to build up (as opposed to just slapping a blower on a stock block)... but you can always add blower down the road to get even more power. There are many other reasons to chose one over the other, but you need to decide on your goals and see which fits you better.

[NightHawk756]

Originally Posted by Italian LX

You're statement is basically true, but there is a little more to it -- there are pros and cons to both set-ups. Things like blowers add heat and make more work for the motor... but they also give you the ability to increase power with only a pulley change. An N/A motor will cost more to build up (as opposed to just slapping a blower on a stock block)... but you can always add blower down the road to get even more power. There are many other reasons to chose one over the other, but you need to decide on your goals and see which fits you better.

And on the compression part, sure, 10.5-1 probably wouldn't be bad with low boost and a VERY good tune. But, in my opinion, that kind of limits you a little. As in, increasing the boost will start to get a little tricky and you'll have to put alot of attention to your tune(which your going to do anyway). With lower compression, you can get away with alot more boost safely and have room to play. Even with the tune.

[Italian LX]

Originally Posted by flashbang756

And on the compression part, sure, 10.5-1 probably wouldn't be bad with low boost and a VERY good tune. But, in my opinion, that kind of limits you a little. As in, increasing the boost will start to get a little tricky and you'll have to put alot of attention to your tune(which your going to do anyway). With lower compression, you can get away with alot more boost safely and have room to play. Even with the tune.

Although, if you choose to go with a lower compression because you are going add a blower, just make sure that you don't go too low of a compression based on what size blower you plan on using. Sure, low compression will allow alot more boost safely, but it will also will limit your power level significantly when you use a small to moderate sized boost blower.