Hey all... Wanting more all motor and nitrous power from my c5z so I'm building a 408 on the side for it, to install for next season.

Current setup:

• 346 sbe ls6
• Tfs 220s, as cast, 64cc with ls3 turned down intake valves, btr shaft mount rockers, Manton 11/32 rods, and Johnson st2126lsr lifters
• Holley hi ram with shearer fab lid and nx plenum spacer plate for the nitrous. Katech 103mm tb
• Gz motorsports vacuum pump
• Cometic 0.040 head gasket
• E85
• Btr stage 4 ls3 cam (233/250, 0.618/0.596)
• ATI Balancer
• TSP 1.75" Longtubes

Old setup was tea stage 2 243s(2.04 ferrea intake valve, so dropped about 20 grams of intake valve weight on the new setup), fast 102, ls2 tb, ls7 lifters. This setup on a dyno jet made 470/420 wheel SAE and 418/380 on a mustang dyno.

I am hoping that the car will make another 20 wheel hp out of the new setup (maybe it will, maybe it won't).. But with the added compression and valvetrain stability/weight reduction + the lifters, I see that alone being worth some power. Then if the hi ram shines past that with more rpm and the curve shifts to the right to hold torque out a bit longer, I'm happy.

The new 408 though.. This is my plan so far...

• L76 block, bored to 4.030
• Wiseco K0433B3 pistons (10.4 dome)
• Summit pro ls rods
• Undecided on whose crank (likely btr or k1)
• Same hi ram, tb, plenum spacer
• Same lifters and rockers
• Planning on this setup being in the 13-13.5:1 range.
• I am assuming the cam will need be in the 24X/25X range... Maybe more to carry out with the manifold.
• I'd like to spin it to 7700 or so.

What I am not sure of is what heads to run. The car as it sits, is roughly a 126-128 car on motor with the car weighing around 3250 with me in it. It's a 135 car on the 100 shot. And it runs with plenty of higher power cars on the street.. (mainly a roll race car, I like what I like.. Lol) ...

Now I'm not chasing a particular number, but I would like the car to be around where it is now with the 100 shot, on motor with the 408.. I don't feel this is unobtainable at all and very doable. This would need to be roughly a 132-134 car which would probably be around 550-580 wheel.

Will the 220s do it after being opened up to a 4" bore and softened for the compression and nitrous along with some cleanup work? Or do I need to start looking at putting a tfs 245 on the car? I'm not opposed to the change as I know what kind of results they put down (245s)..

Thanks for any and all advice and if anyone has something similar, please share.
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Based off of the ole’ 2hp per cfm of flow method, you should be able to get 550 wheel, but that’s assuming everything else is on point, including the tune. The 220’s are a terrific head as cast, but you might consider getting them worked to move more air. With the 245’s, your there no problem and more. Don’t over-cam the engine. especially with the high-ram. In my opinion, tune is everything. Don’t skimp on the tune and grab the absolute best tuner you can acquire.

 

This makes me feel good. I had a good feeling that the 220s could get there. I wonder if it would be worth it for AI or Frankenstein (assuming they have a program available for them) to cnc them to a 230+.. or if a good hand port by someone (no backyard shops here lol) would be the better route to go.

Tuning wise, I have no doubt in any of my tuners around me, especially my personal friend I use.

What do you think cam wise off the top of your head?

 

Give TEA a call, they can open up the chambers and do the bigger 2.055(or bigger) cut down LS3 valves. Maybe ask about the nitrous exhaust port, also. Car runs good, if you wanted to go big on your set-up, I would the Brodie or Mast cathedrals. Might look at 84ta406's 402 build. He made 660hp from a cathedral 402 with a LSXRT intake. Ran well and is for sale.

 

I think these two builds that @Tuskyz28 posted in his cookbook are very similar to what I think I can expect from the 220s.

Engine A

LME LS2 402ci
TFS 215 heads opened up to 4.00"
242/246 605/615 113+3 cam
Fast 102mm port matched to heads
NW 102mm throttle body
electric water pump
11.7 compression
621hp/565TQ

Engine B

LS2 407ci (4.022 bore)
AFR 215 heads ported by Tony Mamo
242 duration 610 lift on a 114 LSA cam
Fast 92mm intake ported by Mamo
Fast 92mm throttle body
Electric water pump
11.5 compression
618hp/564TQ

 

Would I really gain much buying another set of LS3 valves to be turned down? The 220s I have now have cut down LS3's at 2.04"

But I do agree that the nitrous port on the exhaust will be a must at this point.

 

Yes, I would do a 2.08/2.100 valve if the seat will go that big. FYI, you cannot bore an L76 alum 6.0 .030 over. About .010-.015 is max

 

A 215 cc head is rather small using the high ram and the want to go 7700 besides being at 408 cubes and 7700.

Min: 235cc
Cam 🤔 240's mid 600's lift...

 

Didn't think of the heads being the rpm limiter. Or more so, power leveling out before then.

 

don't cut your own head off...
from a 408 owner. Trying to be calm rather than Rowdy 🤣.

 

Dave, the L76 and the LS2 are the same block. Those can go .030”. I’ve seen a bunch of guys do it.

 

Was gonna say, I've seen plenty of people go 30 over on em.

Currently talking to Paris Pugliese about working on the heads.. He mentioned he'd like to do a 2.055 valve on them plus whatever other magic he can do on them.

 

I know what you mean, I've seen it done many times too and have it be "fine", but for anything getting sprayed+real rpm I wouldn't trust it.

 

OP,

Your going to have to sink big money in those 220 heads to even get close to where you want to be.....it's simply not cost effective.

Increasing the size of the chambers and the valves wont provide that engine with enough airflow and cross sectional area to spin past 7K. The intake and the exhaust ports will both have to be properly shaped and enlarged. It would be alot of work and it would be have to be done by someone who is very experienced and willing to invest a tremendous amount of time ($$$$).

My advice is to sell them to a buddy or another board member here doing a more conventional lower RPM 5.7 or 6 liter build where those heads can shine even out of the box. Then take the proceeds from the sale and the money you would have invested trying to rework those into a "better tool for the job"

I would recommend my MMS 235 heads.....in fact if you still planned on spraying I would recommend my NFI version that is designed with forced induction or Nitrous in mind. It has a larger exhaust port with a larger 1.630 exhaust valve and flows 270 CFM!

Intake flow is 340 - 345 CFM and it comes with a 2.100 hollow stem lightweight intake valve. This head has made 640 - 660 HP in pump gas 416's with ported FAST intakes and street friendly HR camshafts.

With the compression and the RPM you mention, assuming you cam this engine properly I would expect to see close to 700 HP at the crank.....a vacuum pump might nudge you over 700.

That should put you right where you want to be at the wheels and the likelihood of you accomplishing this is high, versus rolling the dice on the massive rework and cost the 220's would require.

I would help you with the entire top end if you had an interest.....custom cam (recommend an SR), lifters, rockers etc.

Anyway.....if you would like to discuss this in more detail shoot me a PM, email or a phone call.....the last two methods I just mentioned the most preferable



Cheers,
Tony

 

Thanks for the input Tony. I agree that a 235 would probably be the better choice to go with. I am going to wait and see what Paris wants to do and go more in depth on my goals for the car. I can probably unload these 220s and be a touch ahead on cost for a new set of bare 235s.

 

Tonys advice is spot-on and his guidance is always on point. I might be interested in the 220’s if you decide to unload them. The 235’s would undoubtedly be the easier way to get to where you want to be and the end product would be a much nicer driving car with more power on tap. If I were you, I would consult Tony on the entire package and see where it goes. His knowledge is priceless and you will not find better service in this industry, no matter where you shop. Period.

 

Like I said, I agree that I will probably find an rpm limit on the 220s fairly quick and the 235 would be a better option for my particular combination. Honestly, I have known this since I decided to start this 408 build, but I was hoping that possibly someone could show me some proof that they could work for the car and meet my goals, and I think they still would meet my goals of a low to mid 130s car, but probably only spinning it to 7300 like I have prior with the fast. I moved away from the fast due to the lack of options for it runner wise. The only reason I will not go with Tony for a head package is because I am in the stock rocker camp and I just don't want to use a roller rocker because it isn't necessary imo. Stock rockers have proven themselves time in and time out and rollers are a waste of money in my opinion until I get into a higher end jesel or something of that nature for a more radical solid roller.

 

You can run my AFR 235's with whatever rockers you like but you will wear the guides alot faster at the type of RPM, spring pressure, and cam lobe intensity required to meet your goals.

Because you can run OEM rockers doesnt mean its the wisest choice. Do you honestly think they were designed with this type of build in mind??

Here is a picture of the wipe pattern with OEM rockers.....the arc'ed pad of OEM rocker scrubs across the valve levering it from intake to exhaust and back again over time creating an hour glass shape in your valve guides (PM or bronze.....doesnt matter)
Even BTR and other sites recommend keeping lift lower with OEM rockers to reduce that negative situation (more lift creates more scrub and an even wider contact patch). Compare the wipe of the OEM rocker with a YT rocker pictured below it running the same amount of lift (.634).






The roller wheel has a much more narrow contact patch transmitting most of the force on the valve in the intended direction of travel (staying much close to center and rolling back and forth in that tighter range of motion).

So that said its your build to handle as you like.....I make recommendations based on experience and do my best to explain "why" but the ultimate parts choices comes down to the owner of the build

You can run OEM rockers on my 235 heads no different than you can on any other cathedral head (OEM or aftermarket). Your not forced into running roller rockers by any means.

I say this to you and for the benefit of anyone else reading so there is no confusion on this situation.

Yes....most guys I help do run the YT rockers on my builds but they do so mostly because of my recommendation, not because they have to.

Anyway.....don't let the rocker deal sway you from my heads. It's completely up to you if you want to run the OEM stuff.

I have helped some folks who wanted to retain their OEM rockers (and lifters and other things I might have recommended something different)

-Tony

 

Well, that’s settled. You don’t have to run roller rockers if you don’t want to. Call Tony. You’ll be glad you did.

 

To meet the goals you have listed I would highly recommend giving Tony a call. You won't achieve these goals with conventional youtube and ls1tech forum build threads or a speed shops cookie cutter "stage X" combo.

You are getting into that realm beyond what most people here do. There are so many reasons to run the rollers, Roller rockers not only improve wipe pattern for bronze guides, they also vastly improve stability when properly sprung. This results in more of the action from the lifter on the lobe being transmitted to the valve. It also allows you to run higher pressure springs for more aggressive cams and higher lift lobes. Both of these are things I forsee for this build.

What you have now is mismatched imo and will leave you underwhelmed and unhappy. Buy once cry once, let Tony take care of you.