Z28 MeTaL HeAd

Well im finally picking up a set of heads for my 355 shortblock. Im getting 062 casting Vortec heads with crane cams 10309-1 springs and retainers for lift up to .550 w/ stock Vortec heads, screw in studs, poly locks, roller tip rockers, Professional Products aluminum Vortec intake manifold. This will have a Holley mechanical double pumper carb on it.

Now, the 355 has flat top hyperutectic pistons in it that supposedly will give a SCR in the area of 10.5:1 w/ 64cc heads.

I plan on using the 1.5" roller rockers the heads come with just to be on the safe side, but my issue is the cam. I've been reading a lot lately on the tighter and wider LSA's and im not sure anymore what to think.

The cam in question is a Comp XE268-14.

Its 224/230 @ .050", .479/.480 Lift on a 114LSA.

Should this combo work well??

For reference, i used to have an XE284-10 in my old 355 w/ Sportsman II heads. Power was lacluster down low by crazy up top. I want more of an all around performer now, not just top end.

I also have a Lunati Bracket Master II cam kicking around. Its .515/.515, 246/246 @ .050" on a 108LSA. I think thats way to much cam personally. So, a little help/advice/suggestions anyone?

Saabster

iTrader: (2)

Hmmmmm, according the Dynamic compression calculator I used, the XE268 will give you a DCR of 8.6:1. That's running on the running into or very close to detonation territory according to the interwebs. What's the piston CC, deck height and gasket thickness, I'm gonna run some numbers (god bless spread sheets). I think you'll want a SCR around 10:1 for that cam. Or you can run a supr thing gasket and try to the get the SCR up to 10.7-10.8 and run the 284.

Z28 MeTaL HeAd

I dont wanna run the XE284 cam again, i want to run a cam with less duration so i can have low and mid range power in lower rpms...

Im not to worried about detonation as i only use Sunoco Ultra 94 Octane gas in the car. Will the combo of XE268-14 and the Vortecs make power though?

I dont have any headgaskets yet either, i was also going to ask for a recommendation on them. Sonix here said more than likely my compression is lower than what the previous owner/builder told me. Id be happy if it were between 9 & 10.0:1

alvanwie

I am running a similar roller cam with vortecs and the crane spring/retainers. Makes a nice combo for a street machine. Should do well with your 3.42 gear. See my sig below.

urbanhunter44

iTrader: (3)

I don't think that's enough cam, you'll wish you had a bit more duration.

You can get away with a 230/236, maybe a little larger. Try a 110 LSA. With a 224/230 you'll shift around 6k I'd say. With a 230/236 you can probably shift around 6500 and keep your low end with 3.73 gears. What trans are you running?

I ran a 224/230 on a 108LSA in my old M6 LT1 Camaro and it was pretty damn tame.

Stephen

iTrader: (12)

You can't get more than .490 (some report problems at .460 lift) without machining. Yes, those springs can handle the lift, but without machining, you'll still have interference problems.

Rydda

heres the cam im using. i have a similar setup to what you have in that it is a vortec 355, but i have had all the necessary machine work done to the heads. i too have the flat top hypereutectics, but i am using 1.6 rockers which makes the cam below a .514/.522 lift instead of .487/.490. i hope to have it running soon, but with this setup and a 2800 stall i have been told i will be very happy with my choice since it is a street/strip car. i hope to drop the engine in next week


COMP Cams 12-246-3 - COMP Cams Xtreme Energy Camshafts
qty.
Click here to add CCA-12-246-3 to your wish list.

Add to Compare
Add to wishlist

Image is a representation of this part. Actual part may vary.

COMP Cams 12-246-3


$119.95
Estimated Ship Date: Today
Overview Warnings Application Suggested Parts Warranty
Show All
Brand: COMP Cams
Product Line: COMP Cams Xtreme Energy Camshafts
Part Type: Camshafts
Part Number: CCA-12-246-3
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,800-6,000
Intake Duration at 050 inch Lift: 230
Exhaust Duration at 050 inch Lift: 236
Duration at 050 inch Lift: 230 int./236 exh.
Advertised Intake Duration: 274
Advertised Exhaust Duration: 286
Advertised Duration: 274 int./286 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.487 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.490 in.
Valve Lift with Factory Rocker Arm Ratio: 0.487 int./0.490 exh. lift
Lobe Separation (degrees): 110
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: No
Grind Number: CS XE274H-10
Quantity: Sold individually.

Camshaft, Hydraulic Flat Tappet, Advertised Duration 274/286, Lift .487/.490, Chevy, Small Block, Each

Z28 MeTaL HeAd

Im fine with shifting at 6k. The entire bottom end has ARP bolts. Its a 4-bolt main with ARP main bolts and GM 'X' rods with ARP bolts as well. I know it can handle more revs, but this is more of a street than strip car.

Im not worried if the cam is a little soft compared to what i could put in, i can always change it later. I was just wondering if the XE268H-14 will work ok with a carbd Vortec headed 355 due to the 114LSA.

Ive had 110LSA cams, they're nice, but i liked my 112LSA crane i once had much nicer. The lack of vacuum in the 110 cams im not to fond of either.

Right now im running a T56 from a 95 LT1 Camaro. I have a stock 95 LT1 PBR rear end in the car too with 3.42 gears, but ive also got a set of 4.10's kicking around that i want to slap in as well.
----------
These heads were on a 355 before with a cam that had .480 lift already. Im not to worried about the 'lift' issues. The previous owner told me that he made sure the heads were ok to withstand at least .550" lift, so its possible he had all the machine work done, or he could have put the crane spring and retainer kit in with the washer set that raises the spring up higher to clear the guides for more lift.

Z28 MeTaL HeAd

Yea, i hear good things about the XE274 with the Vortec heads. Actually ive heard good things about the XE268 and XE274 with Vortec 350 combo's but the difference is its all the 110LSA cams i read about.

Ive already got the XE268-14 kicking around and it seems like a good choice...i just wanted to see if anyone else has anything bad to say about a 114LSA cam with a carb'd Vortec setup.

alvanwie

No, the kit that he listed uses a different retainer that allows for more lift without interference (no machining required). I don't know about the .550" but up to .525" is definitely good to go.


Actually the 114 lsa will work fine with a carb. Less overlap...so smoother idle and more vacuum. It will have a little less peek hp but will give a broader, flatter torque curve. In general, it will still provide good power, but will make it seem tamer.

I would not go larger than a 274 cam with stock vortec heads. They do not have the flow characteristic for running a 350 at high rpm. You will just start losing power.

Stephen

iTrader: (12)

Interesting....I didn't know those existed. Anybody know what lift height they are capable of handling?

Z28 MeTaL HeAd

The kit is supposed to handle up to .550" without machining according to crane....


Mine have already been checked and verified for this.

Stephen

iTrader: (12)

I looked at Scoggin-Dickey last night...They have Vortec heads, good for up to .525 or some good to .600, ready to bolt on.

Of course, for the price of the .600 ones, your up into the Edelbrock E-tec price range.

F-BIRD'88

The xe268 on 114LSA will work very well.
Especially if you do more hiway driving in OD (5th), than racing.
Especially if you have shorty headers and a 2 into 1 exhaust.

Both the XE284 and the Lunati 246/246 bracket master II cams need lots of rear gear and rpm. 4.10 to 4.56 when used in a 350. 3500 and up rpm. 3.42:1 gears are not near enough for either of those cams.
Wants long tube headers and very free flow exhaust or open headers.

http://www.carcraft.com/howto/116_03...ild/index.html
here is a typical 355ci vortec motor using a near identical 222/234 114LSA crane H-278-2 cam. PN 113801 Crane measures their seat duration different from comp.
.004" vs .006"
This cam and your comp are more alike than different.
Check out the smooth broad torque band from the power graph.
I've used this cam many times. Your lil comp XE 268-14 will run very similar with easy street manors.

Stephen

iTrader: (12)

What about the XR264HR? Looks like it'll pump up the bottom end a LOT. HP up & torque UP!