Rippin92RS

What kind of power could I see out of a Vortec Headed 350 with either a 454 TB or the Holley 670 one (or some other kind, suggestions?)? Also, what kind of powerband would it be best in? Would the LT4 Hotcam be a good choice of cams? I'm eventually going to be doing an LT1 Intake but until then...

-Rippin

Tom 400 CFI

See this?
http://www.indmar.com/engines/engine...e=ind_57_v_TBI
and
http://www.indmar.com/engines/engine...as_57_predator

Those are standard power in Mastercraft ski boats. 310 hp, and Malibu uses the same engine tuned to 340 horse.

Chuck!

JPrevost was trapping at 102 with the smallish cam that comes with the GMPP Vortec 350, I bet that engine would really like a hot cam.

sniper_dsl

I'm having problems getting mine tuned correctly. Getting loads of ping and knock....

I cannot seem to adjust my fuel pressure under 16PSI due to my high pressure walbro fuel pump. Can i cut the spring or something? The AFPR is as low as it goes...

Once i can run 14PSI then i can begin adjusting my timing... currently there is no way she'll run 'right' with 16PSI and various timing adjustment. its just too damn doggy for me when i KNOW she can do better.

What other signs can i look for to determine if i need more/less fuel

oh.. and once you get these engines tuned they run nice and strong

r90camarors

Sniper, what chip are you running? A simple adjustment in the chip will allow you to run a 16psi or higher pressure setting. If you are running a stock chip, whether it be for a 305 or 350, you need chip tuning.
Use winaldl for all your tuning needs. It'll show where you need adjustments at with fuel and timing. http://www.tbichips.com will hook you up for a very reasonable price.

r90camarors

Rippin, as far as the powerband goes, it is obviously dependant on the cam. The vortecs flow just as well up to .450" as many of the high priced performance heads. .480" lift is the max without machine work, so if you plan on an LT4 hotcam, plan on machine work. I run the pro topline vortecs with mild port work, and a .510" lift on the cam w/ 220/230 duration, and an rpm airgap intake, and she pulls to 5,500rpm very nicely even with a knock problem. I'm confident she'll pull more, I just haven't been daring enough yet. Hope that gives ya an idea.

Also, why an LT1 intake?...... First you're gonna have to spend $$$ on one made for the vortecs, then, more than likely you're gonna have to spend even more $$ to get it drilled for a distributor, unless you plan on using the LT1's ignition as well. Stay away from the '93-'94s, I think they use the optispark, and those years are notorius for problems. Anyways, it's just my $.02 that you could spend that money in much, much better places....

sniper_dsl

too late for saving money... lol i've done dropped WAY too much into this project as it is. now i'm just damn determined to get it running with what i've got so far.

its a custom chip from cfm-tech.com whom claims to have specific programming for the Vortec crate motor (gave him my crate motor serial number and he said its the exact motor the chip is programmed for) he also compensated for the EGR, 454, etc. and claimed that the 68lb injectors were perfect for this motor.

i get TONS of knock, pop, and ping under a certain RPM load. the engine is obviously not running right, and i've tried adjusting the timing everywhich way. this only leaves me with lowering the fuel pressure to the suggested 14PSI cfm-tech recommends for their chip. after that i can begin timing adjustment to see if the knock/ping lessens in severity. i've also tried running high-octane with no result.

so how do i modify my AFPR to give me lower pressure? a lesser sping? cut the spring? use a block? i really don't want to spend anymore money and installing a new seperate pressure regulator... maybe home deopt will have a simple shut-off valve i can toss in there... lol

thanks for the advice!

swerve-driver

Are you adjusting the timing on the chip or by twisting the distributor?
S-D

r90camarors

Sniper, what intake are you running? If it is a carb intake, what adapter are you using?
Also, miss adjusted rocker arms could be a part of your problem

sniper_dsl

heh... i wish i new how to adjust rocker arms, because that was my first thought. i tightened the ones i thought were causing trouble and it DID change the tone/RPM which the noise was coming from... but i was too afraid to adjust anymore without proper knowlege of how-to.

i'm turning the distributer manually... this chip is from CFM-tech.com and i don't have the money for tuning equipment as of yet.

although i should have at least two more tries to reprogram the chip though them correctly.

r90camarors

Definetely make sure your rockers are good to go. Too tight or too much play can be causing your problems-valves not opening and closing as they should.
Also, when you're adjusting the timing, you are disconnecting proper wire and following the correct prosedures, right?

Lastly, the reason I ask what intake you're using is because both myself and va454ss are running squarebores and using the Holley adapter plate. The adapter plate is causing our #1 and #2 cylinders to run lean, and thus causing knocks and misses.

sniper_dsl

its the GM vortec TBI intake bored to 2" with a spacer to adapt the 454TB.

does anyone know of a good article explaining how to adjust rocker arms? maybe one for timing too....

yes i disconnect the comptuer wire...

i still believe i should try lowering my fuel pressure. how can i accompish this when my AFPR is as low as it goes (16psi)? will cutting the spring work?

r90camarors

Well, as long as you are disconnecting the esc wire, then the timing is pretty much cake after that. Sounds like you are doing it correctly. But just in case: turn car off, disconnect esc wire, start car, adjust timing, turn off car, reconnect the esc wire. That's it in a nutshell.

As far as rockers go, I don't know of a specific article, I am sure there have been many not only on the internet, but in mags such as car craft and chevy high performance.

The best way from what I have been told, and my perfered method is this:
Line your #1 cylinder to TDC. Both valves should be open, and the timing mark on the harmonic balancer will be at exactly 0, (unless the cam itself is not at 0*). Then tighten the rocker until there is no up or down play in the pushrod. It is alright if you can spin it though. Tighten 1/2 turn and secure the lock nut(if applicable).
Next, turn the crank a 1/4 of a turn. The timing mark should be at 90* to the right. Adjust the #8 cylinder's rockers same as you did the #1's.
Continue this process throughout the firing order. So with the crank at 180*, you would do the #4 next. Then the #3 when your at 270* so forth and so on. I believe the firing order is 18436572, but it should be on your intake anyways.
There are a few things to remember: 1) Do it after the engine has been run so there is still pressure in the lifters, and 2)you can pull the spark plug, and place you finger on the hole to help deturmine tdc for the given cylinder while somebody is turning the crank.

r90camarors

Also, you can change the spring with a lesser one to lower your fuel pressure. But honestly, a 2 psi difference is not going to solve your knock problem.....

sniper_dsl

i thinks its time for a mechanic for this job. i'd like something like that to be done right, not my half-*** ghetto-riggin' ways... lol

thanks for the help i hope this fixes it... should i stop driving the vehicle? could this be damaging till i find time to fix it the rockers?

i commute to college and thats my only ride...

one more thing... could this be causing my 'doggy' power? because i can't seem to find the sweet spot the engine once had....

swerve-driver

Sniper-I agree with the above- see my pm.

Here is a additional info on adjusting valves from CHP:
http://www.chevyhiperformance.com/te...48_0303_valve/

It is not hard once you understand the sequence and reason for it. This is a good article.

I would adjust the rockers ASAP.

regal

Getting back to Rippin92RS 's question, has anyone been successful with the vortec crate + GM ECM TBI? Any Dyno's?

Rippin92RS

Ok, new combo:

350 SBC
AFR 190's
Holley 670 TB or 454 TB
LT4 Hotcam
Edelbrock RPM Air Gap?
Headers
Proper custom burnt chip

Questions/Comments:
1-Good cam choice?
2-Good Intake choice?
3-Which TB?

What kind of numbers/times do you see out of this? Is it even a good combo? My goal is low 13's maybe even high 12's NA. Suspension work will come later. I'm basically clueless when it comes to piecing together motors.

-Rippin

swerve-driver

There are several people on the TBI boards that have done it. The thing I like about it is that I got to keep all the original features of the car: ac, power steering, heat and emmisions and still do 13.8's with very good fuel economy (18.5 city/26.5 hiway).
So if that is along the lines of your definition of successful, then the answer is yes.
Acutally, I didn't use the vortec crate motor, just the bottom end. But, the end results was the same after I put the vortec heads on.
You'd have to search for dyno information.
S-D

swerve-driver

330hp? It is really difficult to do estimates of times and hp numbers for a proposed engine combo. The variations are virtually limitless and it ususally winds up with some un-related pissing match about how this one particular crank shaft is worth an extra 500 hp. Pointless in my view. And yes, I'm aware of the irony here.
I do feel pretty safe in saying that you are not likely to get into the 12's without significant suspension work. Frame connectors, lowering, TA relocation brackets, posi or similar, panhard bar, etc...
I personally did Baer brakes and suspension work first. Then came the engine.
The engine components you put forward would be a good start, no question. Except, if I had it to do over again, I'd do like r90camarors and make a 383.
Best of luck with whatever you go with-
S-D

Rippin92RS

Posi, gears, and SFC's, possibly even LCA Relocation brackets are all coming this Christmas. I'm just looking to build up this motor from now until next Summer, so I'd like to have it all planned out before I start. Thanks for the reply! Anyone else?

-Rippin

JPrevost

zz4 cam + vortec heads + 350 = happy driver
You'll see nearly 400hp if not more depending on the other systems. I wouldn't trust a holley 670 to flow for peak hp but it would do a fine job with the largest 85# injectors. You'll need to crank the fuel pressure way up to support the 400hp but it's worth it. Look into something a little more mild if you don't want the TBI to be a bottle neck.

Rippin92RS

What TB do you reccommend?

Low C1500

I 'm really happy with my setup, tons of tourque, I'd like to see someone put really big cam in a vortec headed tbi motor.

swerve-driver

Low1500
That sounds like an excellent buildup. Please give my regrets to Mr. Sean Brooks and his new RT. Ouch. I must say he has the right attitude- no use sulking.

Rippin-
I'm sure you see what I mean about the futility of hp estimates on incomplete engine proposals. Regardless of actual hp, I'd agree with Prevost's call on happy driver. Your setup would be an excellent start.
Best of luck--

S-D

JPrevost

The Holley would be fine for high 300's in hp but for peak numbers, go with a 4 barrel TBI. Make yourself a 4 injector driver board and go at it. Work on the idle and then with a wideband make sure your fuel pressure is high enough for WOT power. The vortec heads have a good efficiency so the BSFC is on the low side, in the high .40 from what I've measured, that's grassroots measurements so don't hold me to it.