jmswain

Hey guys . So I am trying to figure out what is a good cam with the setup I have now . I know the cam in now is kinda of big for this setup , which is
63-08-468-8 Comp Cams XFI Camshaft, 242 / 248, .584 / .579 113 LSA

And heads are LT4 Heads ported and polished. With-------------------
Valve Springs good up to .625 Lift / Retainers and locks
GMPP/LT4 1.6 roller rockers ( has bowtie on them ) with harden push rods

So I am trying to figure out a good setup up . This is a list of the motor mods

Bored .30 over ( 355ci )
Speed Pro Forged pistons w/rods part # 844-L2252YF30
63-08-468-8 Comp Cams XFI Camshaft, 242 / 248, .584 / .579 113 LSA
Valve Springs good up to .625 Lift / Retainers and locks
GMPP/LT4 1.6 roller rockers ( has bowtie on them ) with harden push rods
Twin 58mm TB Professional Products Part # 69706
ARP Head stud bolts

Head Info Head # 12555690
350
96
2.00/1.55
Gen II LT-4 55 CC 195 CC intake runner Angle Plug
Specs can be found http://outintheshop.com/faq/casting/heads.html

FAD2BLK93

What are u trying to do with a setup? Your goals...track only, weekend cruiser DD?

jmswain

I would like to see weekend some dd during the summer time . I just want a good setup . Looking 420 rwhp Nice low 11 sec .

From what I currently know the car should be pushing 380-390 ish

96capricemgr

iTrader: (1)

So that is what you have?
Have you run it and seen how it performs?
I would be wary of that much lift on GMPP rockers, they had less lift capacity than most.

FAD2BLK93

So what kind of lift would be in ths safe range for the lt4 full roller?

Blk98Vert

iTrader: (2)

Ditch the Flowmaster first of all, you are losing at least 10rwhp. Id back the cam off to around a GM847, its a 234/242 IIRC. I ran a cam just smaller than that and it ran great. With that size cam you should easily be around 410rwhp

96capricemgr

iTrader: (1)

How can you make a power guess without knowing anything about the heads?

GM's stated lift capacity on them is .575 though if you measure pushrod length incorrectly you could have trouble sooner.

jmswain

Went to the track once , I was just out for ***** and giggles and was babying it . It performs decent right now , and pulls pretty hard . But it just seems like the cam is to big for this setup..

I know that the Choke Master AKA Flow masters are holding up some hp there .

So is the cam that is mentioned above a good cam ? And what other things would you suggest ?

nitrous2fast

iTrader: (2)

change to the 280xfi. it's one "size" smaller... or you could run your cam with a few more degrees advance to lower the power band. also you could change to 1.5 rockers but you will mixed reviews with that.

96capricemgr

iTrader: (1)

IMO you have a benchracer's dream there that will not actually work well when truly tested. Ported LT4s are not right for a 355 within the pcm's limits and a cam that big with heads that big will peak north of the pcm's limits IF the porting is decent.

I would go out and truly test it before changing it though, see what it does and set a goal of what you would like it to do.

jmswain

How do you advance the timing on an opti ? It would have to be done with the pcm right ?

jmswain

I ran it at the track went 13.7 @ 96 mph , I launched at 1500 rpm's because I was nervous about the 10 bolt rear and snapping it . I had shitty tires ( seriously no joke ). It was in Nov at MIR . And I was running rich .

So I fixed the running rich part , have new rims and tires now .

So now I mean I would like to know what I can do to change this without spending a **** load of $$$$ .

96capricemgr

iTrader: (1)

Is the car still together? If so examine the rockers and see if there is any indication of interference, long as that looks good try and run it again to get a better idea where you are.

For comparison though I have video of my beast running 12.7 at I think 107 on some old 17" Bridgestones with the slicks and tools in the trunk(at least 4400lbs total raceweight) immediately upon arriving at the track which is 150miles from home. That was on the old smaller heads, smaller cam, less gear, less stall setup that ran 11.9 on slicks.
Even if you are underperforms as I expect it to you should still be able to get some 12s on a street tire and see what the mph is which will give us some idea of potential.
My current 11.5 setup runs 93mph in the 1/8th so you must have really babied it and granny shifted to run 96mph.

guppymech

iTrader: (7)

After you got out of the hole did you whale on it? Cause your mph is not good for your mods.

joelster

I had that cam with TFS 195 heads which are very similar to LT4 heads. They both flow about the same. Mine were mildly touched up, and probably flowed around 255ish give or take a little. It made peak around 6600. Pulled really strong from 5k-6600, then fell off a tiny bit way up top. I shifted at 68-6900, just before the pcm limit. I ran a single plane intake as well which helped it breathe up top. My best was an 11.11 at 121.65 in 1250ft of DA. I wanted to run a 10.99 but the air never gets good around here. My car is light and setup pretty well though.

IMO it would be a waste of time to swap cams for something just a little smaller.

jmswain

I did push it to the floor and I was hitting roughly 6k on the rev .

Car is still together , and the rockers are fine , no clearance issue , I took the valve covers off about 2 months ago and made sure they were good .

CustomX

iTrader: (1)

You need a tune to really see what your current setup is capable of, that pcm for less mail order tune is really holding you back in my opinion. You probably have another 20rwhp on the table if not more.

acerman

Help a newbie,
I see a lot of posts referring to a Mail Order Tune. What is that?

englundjd

talk about bringing threads back from the dead... a mail order tune is when you send your pcm off to someone to have them put a tune on it, then they send it back. There known to be for the most part just a baseline tune there nothing fancy and most cars dont hit there potential. Most mail order tunes are good enough to drive around on until the car gets dyno tuned

bufmatmuslepants

iTrader: (3)

mail order tunes are also fine for mods that are very common, as tuners have normally tuned hotcam or cc503 or 306 or bolton only cars a ton of times on the dyno, so they just send you that tune for $100-200 through email and you load it yourself with your computer, or they send you a little computer you plug in and download the tune then mail the thing back.