[westcoasting]

Hi everyone, first post here so bear with me! Here is where i am at... i have a 1990 chevy 1/2ton 4x4, 305 engine. All was good until i bought a small RV trailer.... Now i want more power (who doesn't)

Right now i tow in drive (not overdrive) and power is seriously lacking on hills etc. I don't need to set speed records, but i do like the thought of a great engine in front of me.

I am thinking about either building a stroker 383 motor or find a 400 and build it.

If i buy a 350 what year motor should i be looking for or does it matter? And same question for a 400?

[DoubleVision]

First off a few questions. Is TBI injection still in use? If it is do you want to keep it or go to a carb? How many miles are on the 305? What size tires are you running? Overall, you dont need a 383 or a 400 just to have some extra grunt in front of you when a 350 with carefully selected pieces is more than capable of the job and costs considerably less. Finding a 400 is next to impossible and if you do find one it will be rather expensive. Also keep in mind if you plan to keep the injection and go with a larger engine means the computer and many other components will have to be changed and if you add any performance parts the truck has to be taken to a shop that has a dyno and can tune the chip on the spot and this is a very expensive process. If the 305 doesnt have really high miles on it with the right pieces it too can be brought back to life on the cheap which would avoid alot of work and cost.

[Valkyrie5.7]

Whats the gear ratio for the truck? The pre-96 305s weren't much on performance in the trucks but a deeper gear ratio (like 3.73s or 4.10s) and a free flowing exhaust might be all you need.

[westcoasting]

Ok so gone is the idea of a 400... i didn't know they were hard to come by. And yes TBI is still going to be used and i had planned on getting TBIChips.com to help me out with a 350 swap.

My engine is getting tired right now and one of the main reasons to build another motor is that i use the truck daily so i was wanting to build a motor over time and then toss it in there and go.

My thoughts are that if i am going to buy another 305 i might as well buy a 350... and if i am going to build a 350.... might as well stroke it.

I had already planned on buying the following whatever i do... new bottom end components, new heads or rebuilt vortec heads, cam, intake, TBI mods, headers, and right now i am not sure what else other than the regular components every engine would need.

Also i used to own a truck with a 400 and i remember the power it had compared to my current 305... that is how i got going on the idea of a 383.

[Pre-Tuner]

I don't know how much extra power you want, but keeping the TBI depends on what you want. I built a mild 350 and went through TBIchips for the chip burning. This did not work out so well and I eventually ended up buying all of the crap to burn my own chips. It took me a year to learn it but I got pretty good at it. I believe he knows what he is doing, but every engine/truck/combination is different and sending chips back and fourth was a waste of time. Luckily mine was not a daily driver. He will need datalogs and even then expect to send the chip back several times. My truck wouldn't run with the chips he burned and after doing it myself I could see why. There is just so much information to take in and so many variables to adjust for you almost have to have the truck in front of you to do it.

Anyway, if simply upgrading to a 350 with nothing done to it would work for you, you can get the injectors (or complete TBI) and computer with the correct chip in it from the junk yard. All of the sensors are the same and you literally only need to swap the computer and injectors to make it run. Plus, 350's are pretty cheap to rebuild.

When you start adding exhaust and intake, the computer will adjust some for it though a tune would be ideal. A cam swap is almost out of the question without tuning. Years ago I did a 4.3l with an Edelbrock cam and Edelbrock sent me a chip for it. It seemed to work out ok, but it's pretty much one size fits all, though still better than a stock chip. I'm not sure if they still do that or not but it would be worth checking into.

I have almost the same truck as you but mine is not a 4x4 and is my hotrod as now it sports a 406 that I built (I have a journal of the build in the link by my username). The 400 build was not cheap but it does have a ton of power. I live in Washington State and had no problem finding virgin 400 blocks but have heard of people everywhere else having problems finding them. Oh ya, and after thousands of dollars in upgrades to make the TBI work, I now have a carb and couldn't be happier with it. It doesn't have the finesse of the TBI on cold mornings but it hauls *** and thats what I wanted.

The swirlport heads found on the pre-96 350's will give you more torque than the Vortecs down low where you need it for towing. Also, with the Vortecs you are stuck buying an expensive intake to bolt the TBI to and then you will also need the tuning to go with it. If you were going to do that anyway, then I would build a 383 since it doesn't cost a whole lot more compared to what you will be spending. The extra torque would be nice when towing also.

[DoubleVision]

As Tuner said, its very difficult to get anything out of a TBI and getting a chip burned is very hit and miss. To keep the TBI and go with a 350 your going to need new 350 injectors as well as a 350 knock sensor. Adjustable fuel pressure regulator, and a in line fuel pressure bung. However if you are going to go this route I have a set of Venom TBI injectors, a edelbrock chip, adjustable fuel pressure regulator and inline fuel pressure bung and it's all for sale. Shoot me a PM if your interested. The Venom Injectors are a big help over stock. They flow 10 percent more than stock injectors. I'll also add they only have about 15,000 miles on them. On the chip thing thats why I said dyno and on the spot burner, as most of the time the mail order chips don't work. You will also need to check your TBI throttle blades for wear. Grab it and give it a shake, if its got excessive play then it'll need replaced. I hot rodded the TBI in my 92 chevy pickup with the 4.3 V6. Now I'm converting it to '98 Vortec heads, single plane intake with divider plate with a Quadrajet carb and HEI. Not only will it make far more power than the TBI ever did, it'll also get better mileage.

[westcoasting]

This is some great information you guys got!! Thanks for everyones input.

I am not set on TBI.. i just thought it was necessary and gas mileage would suffer if i changed it.

I like the idea of going to a carb setup, it sounds way more simple and a lot less money.

I have been reading on the internet about chip burning and they make it sound so easy... but i see the complications involved can be huge and expensive.

What is involved with going to a carb?

[Pre-Tuner]

For your truck it's just the carb, intake, and HEI distributor. I also chose to remove the ECM wiring that was there to make it look cleaner.

You will "usually" get better mileage with a TBI and removing it is not emissions legal. I can't tell you how much worse it is for me because every time I drive mine I'm on the throttle hard and the secondaries open up.

Some people are good at knowing what parts combination make better MPG's and I believe DoubleVision is one of those people. I'm more of an EFI guy and this was my first carb project and it was not designed for MPG's.

Tuning the chip takes an incredible amount of learning and relearning. It's definitely not for everyone.

[westcoasting]

It's funny i have just never considered or thought about this option. I always assumed that mileage would take a big hit going back to a carb... but now that i think about it, my mileage now is no hell compared to before either!

What about the fuel system, pump etc, that must be different too?

[Pre-Tuner]

The same pump will work but it will need to be regulated. I use an Aeromotive regulator with a return but I'm sure there are other cheaper ways of doing it. I'm using it because I had to with the TBI and it works with the carb.

You might have to do some research on what other people have done with this swap.

[westcoasting]

Yeah i have just started reading a bunch about making the switch.

[tjet]

Do you have regular emissions testing where you live on this truck?

If not, you have a ton of engine options. For a tow rig, I would install either an Olds 455 or 425. This is a common swap & they bolt right up if you use 350 diesel truck engine mounts from a late 80's pickup. For the trans, you would need a BOP adapter or use the Olds transmission

[gerbsinmd]

I'd build a 383 and take it easy on the cam, it'll have more than enough torque to do pull that trailer and can knock down decent mileage. My Dad built one that he put in his malibu that had over 450 ft-lb of torque and got 20mpg with a 700r4 trans on the road.

[westcoasting]

I don't have emissions testing so anything is an option. I do think i will stick with some configuration of a small block chev motor though.

I have been searching around trying to figure out if there is much mpg lost with compareable engines with a tbi unit and the other with a carb. Or is it more the cold driveability of it... I am not really concerned about mpg but just want to know more about it.

I am really likeing the idea of a 383 stroker for it though.