Rise of the Phoenix

iTrader: (27)

The valve angle is not stock, so it allows for you to mill the heads to achieve higher compression while having adequate piston to valve clearance. Wherever you buy the heads from, they will mill them to your desired chamber size.

DavidBoren

Intake runner volume is the number associated with most aftermarket heads. The TFS220 has a 220cc intake runner. The TFS235 has a 235cc intake runner. And so on. The LS3 head is around 255cc on its intake runner in stock form.

Large volume runners tend to have slower port velocity, and can be lazy down low. Higher port velocity associated with smaller volume intake runners, usually helps with off throttle response and early torque production.

Peak flow numbers only tell part of the story.

Dads62

Thanks! That is exactly what I needed.

I'm thinking 220 to 237 is where I need to be. Now just to figure out which one. TFS, PRC or something else.

To be honest I think I'm leaning to the PRC 227 or 237 heads. I need to find out about PTV clearance. The 227 have a small 62cc combustion chamber which I'd love to have for the compression if the PTV is good and talk to a tuner to see how they feel about tuning that high of compression to run on 93 octane.

cduke1780

iTrader: (2)

I guess just to clarify, do you already have a complete LS3 or just a LS3 shortblock??

If you have a complete engine, I may differ from the others go to with cathedral heads.... If you go with the PRC or TFS cath heads you are stuck spending at least another 1k on a fast intake and TB to go along with it because a stocker will be your bottleneck at that point. Then you need a matching custom cam, fresh lifters, maybe injectors.... etc.

If you already have a complete LS3.... I would lean more towards sending the heads you already have to Frankenstein, AI or any other company (Wegner did mine) to have a port job and a quality valve job with good springs. If you don't already have them, spending a couple hundred dollars on the hollow intake valves will be a good investment. At the same time, you might as well have the LS3 intake ported (may not be worth it to buy the LS3 Fast intake). Then have Martin, BTR, Cammotion, or any other company custom spec you a cam to match your heads and intake. They should be able to work within your constraints of not wanting to flycut your pistons and you drivability goals... This may be the most cost effective way and will use most of what you already own and making power.

Caleb

Dads62

Yes it's a complete LS3.

I'm not trying to make the most power possible. The whole point for increasing the compression and adding a cam is for sound. It's going into a restomod that had a 12:1 327 in in from the 60s and 70s with a 32x/32x duration cam and I want to replicate that sound as much as possible. There is no way I am adding a cam that radical though. I realize the the LS motor is a different animal and will never sound the exact same but I want to do the best I can.

Simply adding a cam will make me lose the low end torque and that is something I want to avoid because it's will be driven around town 90% of the time. The other 10% will be road trips. I doubt this car will ever go to the strip.

Pretty much everything I've read says I can't mill the stock heads enough to get the compression I want with a cam so that is the reason I started looking at heads.

I've reached out to the forums looking for advice or similar builds but pretty much everyone is looking to make the most HP possible so I have tried to educate myself as much as possible amd come up with a feasible combination that is not a dog once assembled. I have reached out to a few of the cam guys to begin the discussion but so far they have not given me much feedback on combinations. They have pretty much told me they can grind whatever I want.

I wouldn't say the budget is limitless but I can sell the stock heads and intake and a few other things and make a few bucks so that will help supplement getting the new top end.

mchicia1

iTrader: (5)

Keep in mind a cathedral setup is pretty much always going to be more expensive. If you're not after max power, I don't see the point. LS3 setups are always the best budget setups. You get almost a fast and big injectors for $300.

Cathedral you need to shell out $1k for the fast and $2-300 for larger injectors.

Dads62

I'd be fine with the LS3 FAST setup and injectors and possibly TB if I knew I would keep the low end torque. I would still replace the heads for the compression.

If I were going for max HP I could find 100 build threads and copy or come up with a combo I would have confidence in. Finding threads where people are worried about low end torque vs top end HP is a whole different story.

What would your recommendation be for me? Fast intake and injectors? What about heads?

Rise of the Phoenix

iTrader: (27)

He's not talking about a FAST LS3 intake. What he means is the LS3 intake flows very well, and is on pace with a cathedral port FAST intake. You'll be fine with the LS3 intake if going with LS3 heads is the route you go.

If you're sticking with the LS3 heads, have someone do you up a custom cam, end of story. Emphasize to them that you NEED low end torque and are not all that concerned with top end power. The cam guy can tweak the valve events to create a cam that will be ideal for what you're wanting. I would also shoot for max compression. I understand that you probably don't want to fly-cut, so you'll have to keep that in mind, but your cam guy can direct you as to what chamber size will have adequate clearance for the cam he specs out.

Dads62

I have no problem with a custom cam. I reached out to probably the biggest cam guys on here through PM and didn't get far. I'm waiting to hear back from TSP. One reason I am leaning to TSP is they are reputable and they sell the packages with heads and cam so I know it works in my motor. They could prob tell me pushrod length and rocker also.

Sounds like I am full circle again with the rectangle port heads. Mast 240 heads? PRC 255 milled to 64cc or so? Other?

What need is someone to tell me yes the Mast 240 or PRC 255 milled to xx will give you plenty of ptv clearance with a .6xx lift and 23x duration with a xx length pushrod and 1.xx rocker. Then I could move on to the cam and let the grinder know what I have and the performance I want.

Am I not going about this the right way?

Rise of the Phoenix

iTrader: (27)

If you're going to use Texas Speed, then buy the heads and cam from them. They should be able to tell you that if you buy and use the PRC 255cc heads, you can mill them to "x" cc and still have adequate clearance with whatever cam they say will work best with your setup and what you're looking for in terms of performance and RPM range. I would suggest giving them a call and talk to one of their guys. Be very specific when you talk to them in regards to what you're looking for in terms of lower RPM power/torque and that you want to run maximum compression without having to flycut. They can get you there as long as you communicate with them and ask lots of questions.

mchicia1

iTrader: (5)

Stock ls3 intake, rails, and 42 lb injectors for $300-$350 on ebay. Another plus is you get stock GM injectors which have publicly available injector data.

And yes, the aftermarket heads give miles of PTV. You do not have to worry about PTV, although I'd always measure just to be certain. But yes, if you want a big cam without flycutting, you have to get the mast or prc heads.

yet another positive is you can run factory rockers with the aftermarket square port stuff. I believe on trickflow cathedrals you need roller rockers.

Dads62

So I called Mast and TSP to talk to them about my setup. Both were productive conversations but I came away with positives and negatives.

Mast 240 heads
$4550 for heads, cam, push rods

TSP/PRC 255 or 260 heads (they are discontinuing the 255)
$3000 for heads, cam, push rods

There is no way I can justify spending $1500 more for the Mast setup.

TSP told me to use a cam off thir shelf because "they have pretty much figured out what works through their research" (I'm paraphrasing). I asked him then about using the MS3 cam they have and he said that was mostly a cathedral port cam. He then pointed me to their stage 3 or 4 cam but I can't remember which. I reminded him I want to keep the low end torque and limit the low rpm bucking and he said that the stage 2 cam would be the one I want.

Not sure how I feel about being told to use a shelf grind on custom milled heads.

He said milling the heads to 65cc would put the compression at 11.8:1 and that would be too much for pump gas but I have heard/read that tuners can tune 12:1 to run on pump gas. He said milling to 67cc would give me 11.5:1 and that was about the most pump gas would take.

Not saying I want 12:1 but I would love 11.8:1 if possible. Is it? Does it take a really talented tuner to tune that high to run on pump gas? Or can pretty much any reputable tuner manage it? Will a cam guy be able to spec me a cam that would allow 11.8:1 on pump gas or am I dreaming?

This brings up another point. Was thinking on switching out the ECU from stock to Holley ECU. Not sure which series yet. I've read the Holley systems have more tune-ability than the stock systems. If so will a Holley system allow me to get to 11.8:1?

Thoughts?

Rise of the Phoenix

iTrader: (27)

11.8:1 is fine on 93 with a good tune. Any reputable tuner should be able to safely tune your car. As for the stock ECU, I would just run that. You are no where near the point where you need an aftermarket ECU.

mchicia1

iTrader: (5)

And this is why you typically don't see many MAST builds on here. They are the typically the most expensive by a large margin.

You see a few builds with them on YB, but they are always in all out drag cars, so it's hard to quantify the value.

Martin Smallwood

iTrader: (2)

If this is a LS3 stock bottom end, I'd go with TEA TFS 225's. They have plenty of cross section and flow to feed a 376" engine, and they will make big power without sacrificing bottom end torque due to the amount the heads flow and because the cross section isn't overly large. High flowing heads with smaller cross sections produce more port velocity which is helpful in filling the cylinder at lower engine speeds.

I've seen LS3 bottom ends with TEA TFS 225's and Fast 102's make over 500rwhp with a decent sized camshaft. The 225's also have a 65cc chamber which will give you 11.3:1 compression and more piston to valve clearance than a stock LS3 head on a LS3 short block due to their 13.5* valve angle and reduced valve diameter. 11.3:1 is also more compression than a stock LS3 engine with LS3 heads.

With the TEA TFS 225's, good compression and a decent sized cam you can have a real torque monster on your hands and an engine that still produces excellent top end power.

I can get you set-up with the TEA heads, custom cam, intake manifold, TB, injectors, lifters, gaskets, push rods, fasteners and anything else you might need to complete the project.

Hope this helps.

KCS

iTrader: (20)

11.8:1 isn't a problem on 93 octane, but it's pushing it. When you get closer to 12:1 like that, you have to pull timing out to keep it from detonating. You don't really make any more power, you just lose efficiency. PatG has a "recipe" for 500whp LS1 and it was around 11.75:1, so it can be done. He's in Victoria, TX too...