tbichips.com (Brian Harris). Useful or Not?

[fastacton]

I second Dave's recommendation on the throttle body and ECM. I just swapped over to the larger throttle body on a similar engine and it was a big help. I tuned it first with the 7747 but am about to swap over to the 7427 whenever I have time to start tuning again.

[lionelhutz]

I like the engine but personally I'd put a little more cam in it.

[Hog]

That engine is a stock Vortec 350 with 4 bolt mains. Its rated at 255 sae net hp @ 4600rpm/330 sae lb/ft torque@2800rpm.

Put it on an engine dyno and you will see about 310-320hp. The stock Vortec 350 engine is the Chev Performance 350HO/330hp crate engine with a slightly milder roller cam. TCHev Performance Parts charges you almost $1000 more for the same engine that has its 191º/196º roller cam and roller cam equipement swapped out for a flat tappet cam and its flat tappet equipement. Marketing hype, buyer beware.
The 350HO runs that flat tappet 212º/222º cam 0.435/0.460" lift (based on the 65-67 327 IIRC) it has a slightly choppy idle, while the 282(2bolt) and 283(4 bolt) Vortec 350's run the 191º/196º 0.412"/0.428" 111ºLSA roller cam that was used in the 94-96 iron headed Caprice LT1(Impala SS) sedans and wagons and Cadillac 350's, as well as the 94-94 4.3 V8(yes VEE 8) L99 engine (200hp/240 lb/ft torque), this cam was also used in every 230hp@4600rpm/285lb/ft torque@2800rpm Vortec 305(rpo L30) AND 255hp/330lb/ft Vortec 350 (rpo L31) from 1996-2003.
Lets just say its a very popular roller cam for OEM GM applications requiring solid low rpm torque.

The 350 hp Ramjet 350 that everyone gets horny about is merely the engine you are looking at, with 3 basic differences
1) the Ramjet 350/HT383/GM Marine 196º206º 0.431"/0.451? 109ºLSA roller cam,(worth about 10hp)
2)1.6:1 full roller rockers(worth about 10hp)
3)of course the Ramjet intake manifold (LT1 intake for Vortec heads)(maybe 10hp with its short runners vs. the runner design of a dual plane carb intake)
So all tolled, the Ramjet 350 and its 350 hp rating is the Vortec 350 (p/n 283) engine with about 30 hp or 6% more power. The big claim to fame of the Ramjet crate IMO, is that its a self contained injected engine where you add fuel, electricity and whammo you have an EFI engine. But even these engines require recalibration as they are horribly rich at WOT, but I understand what GM is doing. Rich is safe and will help when marginal fuel systems are used.

I personally would use a 1 5/8" primary header. (but your 1 1/2" primaries will work great for off idle torque.
I would also use the Edelbrock Performer RPM Vortec intake as it helps with power while not loosing torque whatsoever off idle.
For warranty reasons the cam would stay. I shift that cam at about 5500rpm for best et. due to the huge rpm drop of the wide ratio 700r4/4l60e trans, even though the stock 4.3 Vortec V6 DCLF TC I use helps a lot with that.

You've got a solid foundation there, I often recommend that 12530283 engine to anyone who is considering rebuilding, freshening or otherwise paying a machine shop to do a stock rebuild on a TBI 350 or Vortec 350. For $2000 you get yourself a roller cam equipped 300+hp 350, with forged PM rods, a strong nodular iron crank and hypereutectic pistons.

Shop around I sometimes see that engine for $1800, Jegs, Summit, Crate Engine Depot, SDPC all have varying prices on the same 4 bolt 12530283 4 bolt Vortec 350 engine. I have beat the snot out of my 2 bolt version, with hundreds of 1/4 mile passes, thousands of street 0 to whatever WOT passes, 0ver 300,000 miles of daily driving/winter/summer miles and the only time I had to pull a valve cover was to swap out some intake gaskets. (I suggest the FelPro problem solver and yes they are ridiculously expensive, but will pay for themselves in the long run. Esp since you are planning to run an aluminum intake on your iron heads. These GEN 1E Vortecs have the 8 intake bolt in a vertical fashion, and clamp down on the gaskets at an angle which cause the gasket to roll under intake torque and induces a shear stress as the gasket rolls as the aluminum and cast iron expand and contract at DIS-similar rates. The stock Vortec 305/350 encapsulated silicone intake gaskets back in 1996 when the Vortec 305/350 came out were branded as re-useable. This proved hugely false, and GM went through a couple versions, but Felpro came up with a steel structure/rubber coated version which stand up much better than the plastic OEM GM versions.

Since I went with these gaskets, as well as with the marine intake manifold(which features a cast iron lower manifold and aluminum upper plenum(while the stock Vortec 305/350 96-03 truck manifold had an aluminum lower and plastic upper) I have had zero gasket issues. The OEM GM 11 lb/ft intake bolt torque final spec is a little low, I tend to exceed that by a few lb/ft.

In the Centralport Sequential Fuel Injection (CSFI) 96+ applications, the poppet injectors flow 23.4 lb/hr@ 63 psi of fuel pressure. The marine intake I am running uses a 25 lb/hr EV6/Multec 2 injector to fuel the marine 350/377/383 marine engines with ratings from 260-340hp. I had the stock marine injectors flow tested and they were all pretty close to 25 lb/hr at 43.5psi or 3BAR of rail pressure, the marine fuel pressure regulator operates at 58psi or 4BAR of fuel rail pressure which brings these injectors up to approx. 28.9 lb/hr.
The OEM Vortec 350 FPR operates at 63 psi which has the poppets flowing at 23.4 lb/hr.

Your setup with this Vortec 350 longblock with headers and intake will easily be outpowering the 230hp/385 lb/ft 1990 454SS engine, and the uprated 405lb/ft 1991-1993 454SS TBI truck engines. And will do so with the lighter smallblock design, lighter transmission, and do so besting the 454 TBI's 9/10 mpg 1990 230hp 454 engine/3l80(thm-400) 3.73 gearing combo and the 10mpg/11mpg highway 1991-93 255hp/4l80e 4.10 gear combo.

My buddies hated my 1997 Vortec 350, 3.08 gear, 4l60e truck when racing their 454SS trucks. I would run right beside their 1990 SS chipped/exhaust trucks when I was stock, running the 1/4 ,mile beside them using only 1st and 2nd gear(trapping at 5500rpm in 2nd). When I went to a 4.10 gear, PCM tuned combo, I was embarrassing them and they didn't want to play, esp. the one guy that had the uprated 1991 version.

There was a 1996 1 ton van application which used a Vortec 350 with a TBI intake designed for the Vortec heads. IIRC This combo was rated at 235hp and 340 lb/ft torque. This the intake that Chev Performance Parts(was GM Performance PArts) sells for aftermarket TBI usage on Vortec/Fastburn/Bowtie Vortec heads.
This TBI/Vortec combo was also used on some export trucks as well. This OEM Vortec combo used the BBC 2" throttle bores, and specific injectors that were not the BBC injectors, nor the "Cop Car" injectors. It even had its own BroadCast Code of BRDW which is for the export Vortec engine/TBI engine.

1project2many supplied the calibration in post 19 of this thread.
http://www.gearhead-efi.com/Fuel-Inj...tec-shortblock

One of the best things you can do for your squarebody TBI truck on 35's, is to ensure that you are geared correctly. I daily drove with 4.10's on 27" tires, so you should be on at least the same or lower gearing such as a 4.56, esp. if running an OD trans.

Good luck man, the ECM tuning will make or break you combo. Mr Harris is a nice guy and means well, and has some excellent combos. But the guys here seem to uncover many issues with his chips.

Sorry for the novel, but having done lots of Vortec 350 work, I get excited about these good old GEN -1E engines. No matter what is said, the newer engines do not match these off idle torque.

Keep us filled in on your project.

peace
Hog