Joseph@SDSC

I am thinking into the ideal of building a 383 for my TBI truck. I have build 383's for TBI trucks before, but thinking how I could squeeze a bit more power out of them.
Here's what I'm planning sofar:

• 350 Roller Block .030 over (1-piece rear seal)
• 383 Crankshaft
• 5.7 Connecting Rods
• Flattop Hypereutectic pistons
• Compression 9.0-9.5?
• Balanced reciprocating assembly
• Possibly using Stock Vortec heads? w/TBI manifold
• Camshaft = I:.431" E.451" I: 196@.050" E: 206@.050" 109 Lobe Centerline Hydraulic Roller Camshaft

Going conservative on Camshaft for Torque production.

I'd probably have to do some minor ignition tweaks. What I'm curious about is recommendations on the Fuel system, as far as TB and injectors, and Fuel pressure. Not sure on the PROM either---I do know it will start and try to Idle as I have built similar combinations, only difference is the vortec heads, and roller camshaft instead of flat-tappet.

I think I could get close to 400lbs of Torque out of it, which is all I want for a pulling vehicle, fuel mileage would be nice too Has 3.42 gears now, 4L60E transmission.

I could just see what Desktop Dyno 2000 estimates on it too.

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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM ZZ4 intake manifold, ZZ4 roller camshaft)
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM ZZ4 Intake, Edelbrock 750, eventually will be Ram-Jet)

[This message has been edited by Joseph@SDSC (edited May 10, 2001).]

Joseph@SDSC

Here's the first Dyno Simulation from Desktop Dyno, granted its not exact, but torque curve should follow this pattern I feel, probably not as much considering this is a TBI engine.




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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM ZZ4 intake manifold, ZZ4 roller camshaft)
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM ZZ4 Intake, Edelbrock 750, eventually will be Ram-Jet)

FastBroker

That GM roller cam should be ok in an EFI 383 for grunt! (bet you didn't know I'd catch that cam maker?) I'm sure you know that this cam (with 1.6 rockers to gainmore lift) makes the 350hp 350cid RamJet 350 its power, and is the cam used in the 383cid torquer GMPP crate motor, with 1.5's.

The only problem that MAY arise is that lobe sep might be too small. The RamJet's don't used Closed-loop speed density like the RamJet's simple pre-programmed marine EFI. ie, a programmed EFI can be tuned around any cam easily, as GM did. A lobe sep of 109deg MIGHT cause hissy fits of the OEM GM TBI system, but IMO, I would try it because of the lower .050" durations helping to minimize valve overlap. Especially in the 383, you'd have a better vac signal to the MAP.

I almost tried that cam in my 350 TBI but went with a Hot Cam instead, 112ls. Tried it for a week, too much tuning/Prom burning from the prev cam so I went with a Comp XE250-10. NICE and 300+hp/400lb-ft!!! Next step is the Hot Cam with the Vortec heads and RPM AirGap w/the small TBI, for now. I'll let you know about the dyno results if/when I get'em.

I'll be calling SDPC in the next couple weeks for a Vortec Head kit and some other stuff. Later and good luck. Keep us informed and happy grunting. I'm a fellow TBI Jeeper...

EDIT: must be nice to work there, huh? Discounts on the GREAT SDPC GMPP prices, how could things be better than that???


[This message has been edited by FastBroker (edited May 11, 2001).]

Joseph@SDSC

I almost have all the GM cam specs memorized... Guess it helps that I get the GMPP Catalog months before they sell it

Still in the planning stages, but just trying to see what I can get by with, don't want to overkill on engine breathing. All I want is torque.
If it works good, I know allot of ppl with these TBI trucks that would want this kind of torque for pulling.
I get GMPP for cost +10%, very good prices I feel. Its great working there. The parts department has it rough sometimes, as they have to wait on the suppliers for parts.

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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM ZZ4 intake manifold, ZZ4 roller camshaft)
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM ZZ4 Intake, Edelbrock 750, eventually will be Ram-Jet)

FastBroker

Sweet deal ya' got!

I tow boats sometimes so I'm mainly for torque, too, but if I can get high-rpm torque, I'll take it...

You should get GOBS of torque if you use that GMPP roller cam setup. If I got 300+hp/400+lb-ft, you should get more. I hope you realize that you WILL HAVE TO MAKE SOME SERIOUS PROM changes to make the most out of the motor. After my final dyno run on the last modified PROM, I ran the motor with the stock PROM (with distributor advanced to 3 degrees before knock counts) and only got like 240hp/354lb-ft (I think), just to give you an idea of how big the PROM changes need to be. This is a result of cam/heads/intake/exhaust/Fuel Pressure being different from OEM. Obviously, a totally different motor than the PROM was meant for. Be prepared to spend a little more is what I'm tellin' ya'. HAVE FUN!

I need the 2001 GMPP catalog, dammit. Haven't been to the local dealer in a bit...


[This message has been edited by FastBroker (edited May 11, 2001).]

Joseph@SDSC

Yep I realize the need to do a PROM. I haven't messed with PROM's much, but I definately know how much of a difference it can make to change spark and fuel tables.
Even on the really new cars I work on---they benefit from custom programming also with mods, even though they will seem to run fine (mostly LS1 cars).

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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM ZZ4 intake manifold, ZZ4 roller camshaft)
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM ZZ4 Intake, Edelbrock 750, eventually will be Ram-Jet)

SCRA rules!

How did you import the desktop dyno pages? If someone will tell me how to do it, I can import the desktop dyno run for my vortec, TBI 408 engine... Thanks.

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'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust

Joseph@SDSC

I took a screenshot, and posted it on one of my webpage directory's. Then I used the img tag to show on this thread.

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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM ZZ4 intake manifold, ZZ4 roller camshaft)
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM ZZ4 Intake, Edelbrock 750, eventually will be Ram-Jet)

steve8586iroc

Joseph, I know you are aware of the egr situation with vortec heads. If you keep the egr then you should be alright with 9.0/1cr, pulling heavy loads might be a problem with more compression. Have you ever checked out the Speed-o-Motive site at www.speedomotive.com ? They have some good info on building engines for towing as well as others of coarse.

How do you like the lt4 hot cam and vortec heads on your 92 maro? And how did you get the zz4 intake on those heads?

Steve

[This message has been edited by steve8586iroc (edited May 11, 2001).]

Joseph@SDSC

The EGR is minor, in fact I believe we have all the parts necessary for the conversion at work. The header would have to be cut open to weld in a bung for the EGR tube.

The intake is from the Fast Burn 385HP, thanks for pointing that out to me, the ZZ4 uses L98 heads...I musta been thinking ZZ4 at the time cause I bought the ZZ4 cam and the two intakes at the same time
The ZZ4 Intake would not line up very well even with drilling and tapping the heads.

The Hot Cam really is impressive, I am building up another 350 this weekend for one of my younger brothers 73 Camaro, will have exact specs as the 92 Firebird.
The Firebird was all done at once, (Engine, Transmission, Gears/Posi) As you can imagine, it is a completely different car now, than with the TBI 305. It has a very nice lope to it too, and the powerband completely matches the rest of the drivetrain, it should run easy 13's. Still needs a little more work, but the major stuff is done. This car is my other brothers car, that was living with me, he moved out so I will probably delete it from my signature soon. I really miss his car, not him though,

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-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM Vortec Intake, ZZ4 roller camshaft) --- Planning T-56 Install in the near future
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM Vortec Intake, 3000 Stall, 3.73's, Auburn Posi)

speedlvr

[QUOTE]Originally posted by Joseph@SDSC:
[B] I almost have all the GM cam specs memorized...


What is the cfm rating of a 350 Rochester throttle body?

steve8586iroc

Looks like I goofed too. I thought the 92 was a camaro not a firebird nor did I see the rest of the sig on gears and stall converter.
Where does the power start to come it at with the hot cam and what is the max rpm this cam is mad to see? I have the hot cam and rpm air gap to go in my 350vortec engine I'm building, I plan on using the 454tb with 350 injectors. I am just curious as to how this cam will act in this combo. I also plan to run a corvette converter or one that will stall in the 1800 to 2000 range with a 323 or 342 posi rearend. Also how much would running 1.5 ratio rockers change the character of this cam? Thanks for the info and hope you build a killer tq monster with the 383.

Steve

Joseph@SDSC

Don't know any of the factory TB CFM's---Like I said, I really don't care for TBI myself, but it may work for what I want in this 383. I'm talking to a friend right now, that is considering buying a TBI truck for me to build the first 383 like this.

The converter I have installed tries to stall at 2200 with street tires. The powerband seems like it starts right away, probably as low as 2600 and will go to 6500 before it craps out. In fact, it really doesn't go past 6500 in gear at all, I tried Although I'm not completely sure what it was at since it still has the factory 6K tach, its funny to see it go way past the 4500rpm factory redline on the tach.
I have heard of ones that use 1.5 ratio rockers, it would have .492" lift with 1.5's---I think it would be fine, although the cam was designed for use in the 1.6 ratio LT4's to begin with. I think the powerband and peak numbers may be slightly different using TBI, but it seems like it can be made to work real well.

------------------
-Joseph
ASE Master Automobile Technician
Scoggin-Dickey Chevrolet

1967 Camaro (Vortec Heads, GM Vortec Intake, ZZ4 roller camshaft) --- Planning T-56 Install in the near future
1992 Firebird (Weiler Vortec Heads, LT4 Hot Cam, GM Vortec Intake, 3000 Stall, 3.73's, Auburn Posi)

Mr.ChevyStroker

So, I know this thread is ANCIENT but I am looking at doing a 383 build, with tbi, either vortecs, or promaxx's, (depending on how much i wanna spend and I was wondering about the prom and all that stuff. Would I be able to take it to a dyno, and be able to get a good tune there since i dont have the tuning parts here and such. My apologies about bringin this back up.