Anyone running the fastburn heads if so wha cam? I just picked up some heads off this forum at a great price. I was thinking of the 10185071 GM cam I think the ZZ3 grind and was going to try 1.6 RR on intakes and 1.5 on exhaust. Using GM simulations the hot cam only makes a couple of more ft/lbs at the expense of everything below 3k and seems like it will idle better easier to tune and run stock stall converter easily.


Next question do LT1 exhaust manifods and headers fit a L98 (91) chassis?

Still thinking about intakes as the heads have some pretty big ports and they are raised around 0.240 as well so may have to weld the roof of most of the usual choices.

 

The ZZ-3 cam works well but I would still choose the hotcam over the ZZ-3. Both cams can be made idle well and the hotcam will have more top end pull. Neither cam will work all that well with a stock 1600 RPM stall convertor, in other words you will feel the engine come up on the cam. I ran the ZZ-3 cam with a stock convertor and it drove fine but when you went WOT from a dead stop you could feel the power build as it hit around 2500 RPM. (In other words both cams will work better with a 2000 to 2300 RPM stall convertor)

In my opinion in the long run you would be happier with the hotcam then the ZZ-3 cam.

 

isn't that cam a bit small? i would think you would want something with a bit more lift to it?

 

With 1.6 rockers on the intake it should workout to
.510/.510 208/224 at 0.050

vs.
.525/.525 218/228

The fastburn heads flow really well as will the intake so I was hoping to run a little less intake lobe to broaden the power band. Big heads and big cam usually mean buzz it to get it going. I am not currently wanting to change the converter though i do have the 3.07 rear instead of the 2.59 one..

I think I will call Com Cams this afternoon and see what they think..

 

i didn't say more duration, just more lift. like a Lingenfelter 74211 Camshaft - 211/219 .530/.560 HR112. i know its not a ton more lift but just a suggestion.

 

The big question will be what intake will you run - TPI style or Miniram. Either way you'll need one for vortec/fastburn heads as the ports are a different shape than traditional SBC.

I chose TPI with the sdpc base and TPIS large tube runners. As for the cam, I have a Speed Pro CS-1065R, which has mild duration but good lift. I haven't intalled yet, but I'm hoping to get a few hundred extra RPM's but improve the mid-range torque while maitaining overlap friendly enough for my small turbos. Something like the TPIS 211 would also be a good choice.

With a miniram, the hotcam would be a good choice since the fastburn heads are very similar to the LT4 design, and you'll get a lot more top-end power with still decent mid-range torque.

Don't let the big runner size of the fastburn heads fool you. It's a taller, thinner port that still makes very good torque despite its size. I'm also running fastburns on my TBI boat, and I picked up 6 mph with fastburns and a ramjet cam on a 5000lb cruiser. If you know boats, that is a huge improvement.

 

I was hopeing to avoid new springs and retainers...LOL the ones on the heads are only good for .535 lift.. Going to give Comp cams a call and see what they say..
I wasn't ready for headers quite yet but see them in my future as the exhaust ports are larger than the L98 manifolds.. I was hoping to initially run the stock manifolds with the 2.5 inch Y pipe I put on a thousand miles ago..

Intake is going to be a Holley Pro Dominator tunnel ram base( I have one in stock) converted to EFI with a fabricated plenum.. I have a nice tig machine in the shop and CNCs lathes etc..

 

Just got off the phone with Comp Cams they suggested the XFI 268 with stock converter heads I have intake I am planning on needs headers that i need anyway to fit exhaust ports1.6 rockers thinking Scorpion there to save a couple of bucks Comp Cams springs and retainers. More than I had planned to spend but promised more than any GM cam might hope for.. Anyone running this cam head combo??

 

if you do intend to use the xfi cam be sure to use the proper comp beehive spring.

 

Was looking at 268xfi hyd roller cam for a fast-burn mini-mouse project. Trying to resurrect some pieces of the original DZ302 performance characteristics in a roller gen1 block. Thought I had made some project headway buying a set of used fastburns to mill to get near the 11.0 to 1 ratio with flat-tops and 3.00 stroke .... just received the heads in genuine fastburn boxes. They have the pn 10088113 stamped in them. They are being returned. Guess Im not going to get any discount on those heads Summit will get some more business from me most likely. Was wondering how the cam choice went ... I see this is an older post. I too see much larger claims by CC Camquest software when I punch in the actual flow numbers from the fast-burns. At least more than was acheived by Super Chevy when they bolted up fastburns to "Dangermouse" . DM is 9.54 to 1 350CI. I had punched in 11 to 1 310CI tho.

I also checked flow numbers of the fastburns at a site CHW? against original DZ and Ford Boss 302 heads and found that at practically all valve lift points under .520 they match or exceed them, some aspect of "swirl" was shown on the flowchart graph originating at very low lifts increasing steadily as well. I think it is a desirable but dont really understand it. No swirl for Boss heads until above .520. HOWEVER the Boss heads continue to increase in flow up to .700-800+ valve lift where the fast-burns virtually flat line at slightly above .520 This is not a problem for me as I dont intend to have valve lift over that. What is the reason xfi cams have to be matched with beehive springs? Not sure the 268xfi is the right cam for me but looked very promising. Trying to safely run a higher compression ratio which I think had to do with a lower dynamic ratio from a high duration cam with relatively long ramps. My project will start carbuerated on a vortech dual plane but end up hopefully aftermarket TBI converted and possibly supercharged.

 

Dont have to run beehives. Personally I prefer a good double spring, up to you. For a street car a head that works well up to .500 lift or so Id take over something that takes off from there but weaker low/mid lift #s.
Your car will run stronger with the first choice.
There is something to peak #s but most toss that out there as a selling point to move inventory. Like "HP", gams, etc. It all sells

 

Another great opinion. Beehive springs do not have enough pressure to cotrol fast ramp speeds. Good ol fassion dual springs.. like isky
Beehives would be great for a stock L98 or LT1

 

Not sure how to select springs other than see what is recommended by cam mfr. Beehives seemed like a good idea for several reasons ... I forget ... my brain is mush today from being dissappointed about receiving the wrong heads I was so happy to have found, the GMPP fastburn heads I will be buying come complete with premium valve train, Im not sure certain springs can be ordered installed. Its possible springs on there will be fine. I see the fastburns flat line at about .520 lift so there is no sense in getting springs that will accomodate more lift. I see CC offers kits which use factory roller parts to complement most of their complete kits at reduced price. I know there is a disadvantage, I forget what it is. Toying with the idea of a custom cam trying to keep dynamic CR as high as possible for pump gas, aluminum heads, and short stroke which may eventually get supercharged. Trying to emulate that DZ302 ... I think CR would effectively increase at higher RPM's because the time for loss to occur from ultra wide duration and slow ramps would decrease ... in microseconds anyway. Giving those high RPM horses some extra chow.

 

If you're sticking with the fastburns .525(?) lift limit, the springs that come with them (LT4/ZZ4) are fine. Keep in mind that the fastburns valves are about 1/3 lighter because their stems are hollow (sodium filled on the exhaust side).

 

not saying that single style springs such as beehives aren't excellent springs; just saying I have read of a beehive failure leading to catastrophic engine damage, whereas with a dual spring, if one breaks, at least there is a backup and some hope of minimizing engine damage.

 

And just so that all who read this in the future know... I had fastburns and 93 LT1 exhaust on my 91 and it was all bolt on and fit great.

 

Comp cam hotline is pretty useless...they'll give you a safe off-the-shelf option

ignoring the intake/exhaust...go 218/218, 220/220. or 218/224 with a 112-114 lobe separation. Go with a lobe that'll give you 550 lift.

Throw the LT4/Fastburn springs away. Go with a stronger units from compcams.

Lastly, don't ignore crane cams (they're open). Their cams will make as good as power than comp cams due to street/strip nature of our driving.

 

Hi Dave,
Yes, the LT-1 manifolds fit in place of the L-98 headers quite nicely: http://forums.corvetteforum.com/c4-t...8-install.html

http://marcmedina.com/LT1manifolds.html

They also fit the Fast Burn heads correctly. I wanted to do the same thing but now that I have to replace my engine it's out of my price range. Just make sure to have your manifold welded up to seal with the taller ports and you're good to go.

The cam I really like is the entry level Lunati Voodoo for the LT-1: http://www.lunatipower.com/Product.aspx?id=2010&gid=288


Hydraulic roller, good idle. Excellent choice for stock to mildly modified engines, works well with OEM style injection systems, great inboard/outboard marine camshaft for economy and sking. Good mileage and torque increase.

• Advertised Duration (Int/Exh): 262/270
• Duration @ .050 (Int/Exh): 211/219
• Gross Valve Lift (Int/Exh): .507/.515
• LSA/ICL: 112/106
• Valve Lash (Int/Exh): Hyd/Hyd
• RPM Range: 1600-5600

And if you order the cam direct from Lunati, they can grind it on a 114 or wider angle at no extra charge to work better with the TPI and also to help with idle quality.