little research on 1990-1995 chevy 350 motor

[kennyhammond]

So I am in the process of looking for a truck to buy for a work truck plan to run 33 or 35 boggers ... My question is from what I see the tbi 350 is a pig .. Is there anything I could do to help it other than the obvious gears ... I am meaning like cam upgrade .. ECT.. I have read the computer is a big issue ..so would going to a carburetor a better choice and ditch the computer all together

[b454rat]

I had a 90 GMC that had a 350 with 200k on it. I put a set of headers on it, already had an exhaust with cat delete. That made a huge difference, it felt like a whole new truck. Check out tbichips.com, he burns chips and has good write ups on building these engines.

[kennyhammond]

Thank you for the information. I will check it out

[special-K]

They aren't such dogs anyway. A lot of jaded people look back at where their higher horsepower modern vehicles came from and see deficiency. I don't know what kind of work you need out of the truck. Why 90-95 and not '96-up with Vortec heads, if a TBI is too lame for you? You can wake up a TBI by putting Vortec heads on, along with a Vortec/TBI manifold

[kennyhammond]

Not against it. I am searching for a 1990-1998 San 4x4 for a work truck ...just know the tbi motor in question is in the year I stated ..

[Kudzupatch]

Originally Posted by b454rat

Check out tbichips.com, he burns chips and has good write ups on building these engines.

Keep reading and you will find his reputation is not so good. LOTS of unhappy clients, several chips burned and people still have modified engines that do not run right. No personal experience but after all I have read I will not use him.

That said, the information on his site seems solid.I have read a lot about modifying these engines and he does seem to know what he is talking about. Just for some reason his tuning my mail leaves a lot of people very unhappy.

[b454rat]

Something else forgot to mention is gears. I think it's the biggest issue with these trucks. My crew cab has the vortec 350 and is an f'n turd. Why GM put a 350 in a 6500 lb truck with 3.73s is assanine. Prolly set land speed records with it, but when I put any type of weight in it it's crazy how gutless it is. Cam heads and compression will make a motor make power, but with TBI only so much you can do.

[Jeepwm69]

Originally Posted by b454rat

Something else forgot to mention is gears. I think it's the biggest issue with these trucks. My crew cab has the vortec 350 and is an f'n turd. Why GM put a 350 in a 6500 lb truck with 3.73s is assanine. Prolly set land speed records with it, but when I put any type of weight in it it's crazy how gutless it is. Cam heads and compression will make a motor make power, but with TBI only so much you can do.

3.73's with 31's (stock size tires) is about right.

When people start slapping bigger tires on them, then yeah, the gearing is off.

That's on the person swapping on bigger tires, not the manufacturer.

[kennyhammond]

Is free gears are a huge factor/help I guess what I was mainly my wanting to ask is you will put let's say 200 in a intake .. 800 in exhaust and maybe another 300 in a stage 2 chip is it worth it .. I have a got that will do the gears and fair price ...like I said I was just curious if intake headers and exhaust wake it up or is a worthless trade for the money... I have a 454 in the garage if I want power just live by thinking the weakest link will break when adding a lot of power or torque ....so don't want extreme

[b454rat]

Even stock gears suck. I had a 92 blazer (first year new body style) that had 3.42s and 265/75s stock. Had to put ur foot to the floor to get it to go. If it was my choice id go with the 454. I did an SAS on an 89 that had a 454, even with 40" boggers and 3.73 it would light the tires up. Exhaust won't get you much, with headers it would help. Im not sure what else helps, I haven't owned a TBI in years.....

[kennyhammond]

The only thing. With the big block I was reading is .. I would have to get the intake changed and would the computer control it like the 350... Or would I need a retune. Its a healthy oval port big block ..not stock. To me it would be the same as pulling the motor and putting a fan and heads in the 350... It all goes back to the computer is junk... So I figure I will hear it for the 35s and headers and intake with a exhast and enjoy the truck ...

[b454rat]

It's not hard to swap to 454, intakes are old school carb with an adapter, and just get a prom for a 454 for your ecm. But 454 Tbi can be tougher to tune cause of the t/b, only so much you can do to them.

[Kudzupatch]

Stock chip would never work with a 454. I know the big block TBI had a different throttle body. I know it had larger injectors and may have had larger bores? I am pretty sure it did. You would need it tuned to that engine.

If you go swapping heads, cam, adding headers to the stock engine you really need to tune the computer to get the most of those modifications. It's no different if you have a carburetor on it, ff you change the air flow you need to adjust the mixture and timing to match the changes.

I never see it mentioned but Holley has a bolt on replacement TBI unit that flows 670 CFM. Stock was something like 450 cfm? Enough for most street engines but if you plan on turning high rpm's of want to generate a lot of HP you would need the extra volume of the Holley unit.

TBI is not bad, it's just that the new EFI engines are much better but also much more complicated. I am going to be replacing mine in my Suburban and while I not going to build a high HP motor I am going to modify with better heads, intake, cam, etc and use the TBI unit. It will require the computer be tuned to match the engines needs. So it will take bit of work but they are so much better than a carburetor.

[kennyhammond]

Sound alike small bolt ons will be my way to go ...and just drive it and enjoy the fun little truck...I figure I need more out of it I will go from there

[b454rat]

As mentioned before make sure you regear. Rough way to figure new gears is divide new tire size by old then multiply by current gear ratio. But I'd jump to 4.56, then have plenty of power.

[manimal]

As for a cam, you can put a 5.7 Vortec cam in it. I just did it to my 93 C3500 and what a difference. Engine idles smoother, revs slightly faster and just runs better. You'll be switching from hydraulic flat tappet to hydraulic ROLLER. You'll need the from cam plate,melonized gear for the distributor(mic the distributor shaft for right size), and a new timing set for the Vortec. TBI engines LOVE this cam.

[kennyhammond]

Sweet thanks.

[kennyhammond]

How did the computer and truck run?

[manimal]

No tuning required. From now on, anytime I do a TBI engine, it will get the 5.7 vortec roller cam/lifters.

[kennyhammond]

So just a vortec cam swap and lifters that's all

[manimal]

AS LONG AS your block is drilled/tapped for the lifter spider then its all bolt on stuff.
Parts you'll need;
cam/lifters/retainers, spider and the 3 bolts, MELONIZED distributor gear(measure your distributor shaft), timing set for the 5.7 vortec, front cam retainer plate and bolts, pushrods(they are shorter than the flat tappet cam's)...DONE. spend the day or weekend and have fun. My truck LOVES it.
You can get the dizzy gear at any parts house or Summit/Jegs

[special-K]

Vortec heads with bump you up 40-50hp. Those mixed with the cam will produce a whole different range of power

[Jeepwm69]

Anyone have a writeup on this? Lots of power, but what does it do for MPG?

[manimal]

But if you run Vortec heads, you will need a special intake if you plan on keeping the TBI. GM sells the intake, it's like $400!!, OR you could do an Edelbrock carb intake and use an adapter for the TBI, but you wont be able to have EGR if you need to pass emissions. The only way for that is the GM intake and a driver side exhaust maniifold from a 96-up 5.7 Vortec for the external egr tube.

[abig84]

Originally Posted by b454rat

Even stock gears suck. I had a 92 blazer (first year new body style) that had 3.42s and 265/75s stock. Had to put ur foot to the floor to get it to go. If it was my choice id go with the 454. I did an SAS on an 89 that had a 454, even with 40" boggers and 3.73 it would light the tires up. Exhaust won't get you much, with headers it would help. Im not sure what else helps, I haven't owned a TBI in years.....

my first k5 blazer had 273 gears and 38 inch tires with a 305 engine, talk about slow. though it would cruise 80mph on the highway at idle also half the time if i got stuck in the mud i couldnt spin the tires in reverse in 4low, i eventually got some 373 axles and that made a ton of difference.

i currently daily drive a 1990 silverado with 220k on my 305tbi. ive always thought that motor was pretty decent in the power area and never felt the need to do anything... but as i mentioned above ive owned some slow under powered stuff so maybe im just used to it.