5.7 TBI to 5.3 Vortec Swap

[Chevyman15004X4]

I have a 95 Chevy Silverado 4X4 that has the 350 TBI engine and I recently purchased a 5.3 engine with 4L60-E Tranny and wiring harnase, computer, motor mounts and all acceries such as A/C compressor, alternator, power steering pump ect. It was a complete pull from a salvage yard from an 2004 Subarben. I was wondering if anyone has done this themselves.

Does anyone make motor mounts for this motor for the older chevy trucks. Im also told when someone changes a computer in the newer trucks, the new vin number has to be put in the computer for it to work. If this is the case, where does the computer read the vin number from the vehicle? (such as an insterment cluster or some other computer with a serial link to the PCM?) I am very good with electrical wiring so you can get as detailed as you want its just Im not very familer with the new trucks (don't own one so I can't explore or expirement. )

Will I have to change my current fuel pump to a pump with more psi or will the multiport injectors run at the same pressure as the 2 TBI Injectors.

Also if any of yall have sugestions on other issues that are not stated but related to this project, let me know. Would also like to know if any other people have thought of doing this to there older model truck. I am doing this since the 5.3 has alot more power along with better fuel milage expecially while towing a trailer, running at over 70 mph and passing people.

I currently get with the 5.7 tbi about 200 hp and around 11-12 mpg at 75 mph or about 16 mpg at 55-60 mph. sucks, don't it. I recently drove my parents chevy Avalanch 800 miles and was astound by what I was missing out on which led me to want to do this. Don't want to by a new truck just due to the pure fact that I like to do projects and like the older c/k style alot better.

[BlenderWizard]

More power and better MPG are always a good thing if you have the means and the way to do it. If you have all the parts to do the swap, go for it.

[BlenderWizard]

Originally Posted by Chevyman15004X4

Does anyone make motor mounts for this motor for the older chevy trucks.

Since you're dealing with essentially the same block, wouldn't the mount points be the same?

[Silverado Brethern]

Just how you figure your 350 only has 200hp!? Anyway, you sound like you lucked in to something real nice. I wouldnt be too worried about the mounts, should be the same. Youl should check with a mechanic or somewhere and make sure you have/get the right pump cuz im not sure that they would be the same. Take you engine out and get all the new stuff in. Then you have an engine and tranny you can rebuild and sell or keep, but i would sell it to get some money to mod the 327.

[Chevyman15004X4]

Originally Posted by BlenderWizard

Since you're dealing with essentially the same block, wouldn't the mount points be the same?

Don't take this to be 100% accurate but I believe when I visully compared the mounts from the 5.3 to the 5.7 that the bolts for the 5.3 mounts run horrizontally all the way through the suspension crossmember and are really long. The 5.7 mounts have bolts that run vertically and are short. Also the motor mount bolt patterns look quite a bit different than the 5.3. Does the 454 or 502 from the older trucks use different mounts than the 350? The reason I don't know what they entirely look like is because I have not yet started the project since its my only good vehicle, I want to get as much info as possible and hear other persons thoughts.

Im still mostly conserned about the digital communications between the pcm and the insterment cluster. Does the insterment cluster store vin number information that is required by the pcm before it will start or is that in another onboard computer such as an abs computer, srs or ect.

Silverado Brethern, the reason I belive it only has 200hp stock is because that is the only about the only number in all of the specs from different books and the internet. Chiltons Automotive manual shows the following,

1995 350 TBI
Horsepower- 200 @ 4000 rpm
Torque- 310 @ 2400 rpm

They could be wrong but if you were to go drive one and try to pass someone or pull something, you would think you have 4 hampsters under the hood instead of a v8. I don't belive nothing is wrong with it because it doesn't smoke, make any noise, no check engine light, runs really smooth and has only 117000 miles on it which is not much compared to some others I have seen with over 200 to 300 grand on. Other than that as you mentioned it was a great deal for the moter... The motor tranny and wiring harnass with all the accesories was only $2600 and they have only 1100 miles on them. Thats pritty much new. (Im 100% sure on the milage)

[BlenderWizard]

Originally Posted by Chevyman15004X4

Does the 454 or 502 from the older trucks use different mounts than the 350?

Yes, those would be different. The 454 and 502 (and 396) are Big Block engines. Chevy has Big Blocks and Small Blocks. The small blocks include, but are not limited to: 4.8L, 305, 5.3 (323 c.i.d.), 327 (yes, they're different), 350, and 400. The exterior dimensions are the same on all the small blocks, and they are the same on all the big blocks.

[silveradoman]

How can you get more power out of a 5.3 than from a 5.7?

[BlenderWizard]

Originally Posted by silveradoman

How can you get more power out of a 5.3 than from a 5.7?

GM was claiming that at the time of the 5.3's introduction. Smaller displacement, but more power/torque.

[twomorestrokes]

I think you are close on the TBI hp figure. That's about all my '95 had. The new generation small blocks seem alot more smooth and powerful. One thing to be cautious of though...what is the weight difference and gear ratio on your '95? It's possible that you may not to get the mileage increase that you are looking for. My '95 got a solid 14.6 with 3.42's, which was identical to my wife's '02 Tahoe with a 5.3 and 3.73's. Also, when the little 5.3 towed any kind of weight, mileage really suffered. A clamshell type snowmobile trailer put it down to close to 10 mpg, probably due to the relatively small displacement trying to pull a little more weight.

[BlenderWizard]

Well, damn, looks like more people think it's a bad idea than the ones who like it. I still think you should do it

[twomorestrokes]

Originally Posted by BlenderWizard

Well, damn, looks like more people think it's a bad idea than the ones who like it. I still think you should do it

Sorry if I sounded negative. Actually I think it's a really cool idea. They seem to run so much nicer than the old 5.7. Just some things to think about before disabling a tried and true package if it doesn't show any problems. Wish I had some answers for you concerning the electronic controls.

If you go through with it, I'm very curious to hear about the results!

[BlenderWizard]

no, all I meant is that we got outvoted in the poll

[Chevyman15004X4]

Hey yall, it nice to hear all your opionions.

TWOMORESTROKES, thats cool. I did't think about the rear end problem but im not sure what gears I have. All I know is I have a 14 bolt rear end and my RPMs at 60 MPH are 2000 rev/s. I don't think it would be too hard to change the front and rear gear ratios if I need because I belive you can order a single set of gears for just under $200. (not sure on quality though)

Hey Silveradoman, No offence but they have been getting alot more power out of these engines with smaller displacement expecially when vortec used the awsome multiport injection system, new aluminum heads, multi-coil ignition, and I belive they have found a better firing order and crank posistions that are supposibly more efficient than the older ones. i belive it is more in the computer system with the Mass airflow sensor (which tells the computer how much air is entering the mainifold so the computer can figure just how long to keep the injectors open for the best air/ fuel mixture ratio of I belive 14:1. They also put on the multi-ignition coil system which eleminated long runs of HV wire, and allows the computer to advance or retarde the timing as much as it wants to as it was limited by the distributer in the eairly engines. And then you add up all the other information sensors ( 4 oxygen sensors, 2 knock sensors, map sensor (also when the engine is off it picks off the current outside barametric air pressue to determine altitude adjustment, electric EGR system, and more) I belive there are about 20 sensors that determin how the engine runs.

And whats worse is that the 4 cylinder car engines have been getting rediculusly high amounts of HP, some new stock cars have way more HP than the older V8s, get better fuel milage and I belive its all because of the electronics systems. For some reason it seems like it took a while for it to migrate to the trucks. I belive it was around 1988 cars started showing up with rail injection while trucks started and just stayed with the limited TBI systems for 7 years but I am not sure about other makes such as ford and dodge. (The only good thing I can think of for the TBI system is its easier to work on then carberators and multiport. They also are more durable electronic wise due to less components and don't flood out when during very hostil off road conditions.)

(Which is why I need more info on the computer systems In the chevy trucks) That must be hard information to get a hold of or find someone that knows about it. They need to make a manual just on the electronics for the engine controls as well as all the other control systems in the chevy trucks that will show all the output pins of each computer and it function. Hell, its been out for 6 years, there should be some more information on it than the little I can find about it.

Well I guess I got of the topic a little and started to b/s a little. Any other Ideas or suggestions or just general info about the engine?

[who fan]

My 01 has the CSK. For gas mileage the 5.3 is good but for everything else my vote goes to the 350.
The 5.3 doesn`t feel like much til your half way up the tach. My old 350 had her down low, much more authority

[BlenderWizard]

Originally Posted by who fan

My 01 has the CSK. For gas mileage the 5.3 is good but for everything else my vote goes to the 350.
The 5.3 doesn`t feel like much til your half way up the tach. My old 350 had her down low, much more authority

Well, numbers wise, the 5.3 has the 350 beat all around if you compare the 5.3 to the last year the 350 (5.7L) was used in the trucks.