270 Rwhp Tbi

**Hiflyer746** · 07-05-2005, 10:19 PM

Now that I have your attention, that is my goal. After much reading I have found that for a little labor and not much money, this goal can be attained. Currently I have an 89 Chevy 3/4 ton 4X4 with the 350 TBI in it. I have a set of flowtech turbo headers on it, 2.5 inch duals to single chamber IMCO race mufflers. I think I have the 193 casting heads. Correct me if I'm wrong. I want to port and polish these heads, as I have found through research that they flow nicely after a good port and polish job. Anybody have any pictures of what needs to be removed? I'm looking to get a 454 throttle body, and do all the mods to it that I can. Anybody know if there will be any problems mounting this throttle body? Anybody know how much fuel the injectors flow on the 454? I'll build my own intake that flows virtually restriction free, any comment on intake "plenum" that will be replacing the stock filter assembly? does highth make a difference? After that I need a cam. Probably will get a fairly moderate cam but may require a stall converter, so I may get a manual. Will the T56 6 speed mount and transfer case? if not, whats a good tranny, that is tough and easy to get? Also, after all this work, what will I need to do to my computer? Keep in mind that I will be mostly running 100LL octane fuel. Thats low leaded aviation fuel. I love that smell:) So tell me what you think guys,and give me pointers, I need pointers. Thanks
Timmy

**CHEV4LIFE** · 07-05-2005, 10:27 PM

A cam.....Crane 2030...enough said

**airdeano** · 07-05-2005, 10:35 PM

Originally Posted by Hiflyer746

Anybody know how much fuel the injectors flow on the 454?

timmy,
it depends on the year model of the injector
1988-1990 were 90lb/hr
1991-1995 were 80lb/hr
your needing this horsepower at what RPM? 5000rpm? your budget is?
in this 6200 pound truck... id think you are looking for 400+ torque more
so than horsepower... and that trans should be a TH400 in 1989.
airdeano

**kdrolt** · 07-06-2005, 06:22 AM

As posted on Thirdgen.org, Fast355 made 279 rwhp @ 4900 rpm and 342 rw ftlbs @ 3400 rpm on a 355 with ported 193 heads using 65 lb/hr injectors set to 21 psi through the stock size factory TBI and factory intake manifold. He also retuned his EPROM (the chip in the ECM) so don't expect to get his results unless you port the heads AND retune the EPROM.

**CHEV4LIFE** · 07-06-2005, 09:39 AM

But it is very reacheable, Id say for under $300, if you want to spend more you can make a little more but for 270HP $300 is the baseline.

**Hiflyer746** · 07-12-2005, 10:26 PM

OK, this is good, I have pointers, I'm getting NV4500 from somewhere, because I want that auto tranny out of there! so a more wild cam is acceptable. I goal here is balls. I want off the line power. I want this thing to accelerate quickly. high end power is good, very good, but torque is also very good. So is a 2030 cam still good choice? how about some 1.6 rockers? yah? nah? I'm going to port the heads, anybody have any pictures for me, just to show me what I need to do. I'm going to get the 454 TB and port that, with the TB spacer and Injector spacer, then after all that, I'll tune the EPROM. Where do I send the computer to have that done? Thanks guys.
Timmy

**BossHogg 77** · 07-12-2005, 10:34 PM

Eventhough you're using a manual tranny, you still can't get too "wild" with the cam - it's not the tranny that dictates this, but the TBI/computer setup.

**1Bad454** · 07-12-2005, 10:40 PM

Is your engine completely stock?
What's your compression ratio?
Is your rotating assembly stock?

**Hiflyer746** · 07-15-2005, 10:56 PM

everything is stock, all I did was headers and dual 2.5's with IMCO race mufflers. Other than that, no changes. I believe this motor to be a 9.3:1 or so compression engine, not sure. How wild can I go with the cam? is the crane cam 2032 too much? thanks

**Hiflyer746** · 07-15-2005, 10:59 PM

one more thing, I know my ol Ford was not efficient, but it had eight 19 lb/hr injectors. I have two 55 lb/hr injectors? Now when I upgrade to the 90 lbers that go with the 454 throttle body, I'm just a CH higher than the stock ford 302 injectors. I know the 19 lb/hr on the ford are not overkill, its almost required to uprgrade if you do any mods really. so why does chevy put so much less fuel capacity capibility in their engines?
Timmy

**Fast305** · 07-15-2005, 11:20 PM

Two 90 lb/hr injectors are good for 280-320 HP(depending on Brake Specific Fuel Consumption) @ the stock 12 psi fuel pressure. At 20 PSI they are good for 375-415 HP. They are good for 147 lbs/hr at 32 psi (factory pressure for the 1994 and 1995 454). That is good for 470 HP @ a .50 BSFC and 523 HP @ a .45 BSFC. All of the above are at a .80 duty cycle. By pushing the duty cycle up to .85 more power can be made. The main reason Chevy used such small injectors is that with the original engine, the specified fuel pressure delievered just enough fuel for idle and just enough for WOT. To fix this, GM makes a Vacuum Adjustable Fuel Pressure Regulator VAFPR, that allows you to have like 10# fuel pressure at idle and nearly 20 @ WOT. If you get too crazy on the cam and injectors it can become difficult to get the injectors to flow low enough at idle to keep from tripping Asynch mode, yet still deliver enough fuel for High RPM WOT operation. The VAFPR lets you have an acceptable pulse width at idle but enough fuel at WOT.