Rebuild or not bottom end 350 tbi

[rotarymedia]

Hello, I have a 90, 350 tbi with 104k miles, it's my daily and I'm trying to get 300-350 hrsprs without runing premium gas, i know its not the most ethical idea and i now all the problems that come with. I already have a set of vortec heads, and shorty headers(cracked manifolds). I'm trying to do it cheap as possible. I'm putting a .480 cam in it, replacing rocker studs, springs, everything that goes with that. New intake with a sniper 2300, I'm going to do a compression test, and leak down test. I'm just wondering at 100k miles with all these mods and around 350 horse would should I replace the rings and bearings, is it a better replace it now to save future money or can I get away with it untill it for sure needs it.

 

[Schurkey]

The mileage on the original engine is the least of your problems.

"Good luck" getting that much power out of it "as cheap as possible".

Will your "Sniper" control the torque converter clutch?

 

[rotarymedia]

The mileage on the original engine is the least of your problems.

"Good luck" getting that much power out of it "as cheap as possible".

Will your "Sniper" control the torque converter clutch?

That's not what I asked I know what I'm doing I just need a second opinion

 

[Das Hatt]

That's not what I asked I know what I'm doing I just need a second opinion

First off, slow down for a minute. @Schurkey is one of the most knowledgable people on this forum. Dismissing his contribution out of hand is a mistake.

Now, the 350's bottom end is pretty sturdy providing it has had regular maintenance during it's life. If you are looking for more assurance you can send a sample of oil off to a lab to get it tested.

 

[PlayingWithTBI]

I know what I'm doing I just need a second opinion

OK, second opinion - you won't get 350 HP with a ".480" cam (what's the duration, is it a Flat Tappet?) and stock, low compression pistons. What will your quench be? IIRC The '70 LT1 350/375HP came with 11.5:1 compression and ran on premium leaded fuel.

Now, on to your question, is it a 4 bolt or 2 bolt main? How long have you had the truck? How often was the oil changed and tuneups done? What kind of oil? Are your Vortec heads cracked?

You can tune it to run on regular, if you're careful.

 

[rotarymedia]

OK, second opinion - you won't get 350 HP with a ".480" cam (what's the duration, is it a Flat Tappet?) and stock, low compression pistons. What will your quench be? IIRC The '70 LT1 350/375HP came with 11.5:1 compression and ran on premium leaded fuel.

Now, on to your question, is it a 4 bolt or 2 bolt main? How long have you had the truck? How often was the oil changed and tuneups done? What kind of oil? Are your Vortec heads cracked?

You can tune it to run on regular, if you're careful.

This is crank horse, I've driven it for 2000 miles, before that it was sitting in my yard for almost 3 years, the previous owner only used it for transportation I don't know about maintenance, it's probably 2 bolt, oil was just changed. As for horsepower I don't know why everyone is saying it can't make 350, from what I've seen it is easy, Richard holdener took a crate tbi, put a 650cfm intake setup on it dizzy, with stock vortec heads and a .489 cam and made 352 horses, aswell cutters performance took a stock engine vortec heads 9:3 compression put a
.525 lift cam dizzy intake ect and made 400. I know these are engine dynos with dyno gas but still. I really don't care if I hit 350 that's just what I estimate base on a dozen other builds

 

[rotarymedia]

First off, slow down for a minute. @Schurkey is one of the most knowledgable people on this forum. Dismissing his contribution out of hand is a mistake.

Now, the 350's bottom end is pretty sturdy providing it has had regular maintenance during it's life. If you are looking for more assurance you can send a sample of oil off to a lab to get it tested.

I'll check that out didn't even think of testing the oil

 

[PlayingWithTBI]

How's your oil pressure cold and hot? Worn cam bearings will lower it. What duration is your cam and, is it a flat tappet? Do you have a part # for the cam?

 

[rotarymedia]

How's your oil pressure cold and hot? Worn cam bearings will lower it. What duration is your cam and, is it a flat tappet? Do you have a part # for the cam?

It's a flat tappet comp 242-2 oil pressure is strong

 

[Erik the Awful]

Will your "Sniper" control the torque converter clutch?

Leave the stock ECM in place and it'll control the torque converter clutch. Mine works fine.

Now, on to your question, is it a 4 bolt or 2 bolt main? How long have you had the truck? How often was the oil changed and tuneups done? What kind of oil? Are your Vortec heads cracked?

If you're not towing nor over 500 hp, 4-bolt mains aren't needed. The bit about Vortec heads cracking is definitely a concern. That's probably the best reason to get your oil analyzed. This should probably be the determination if you need to tear the engine down and do a full rebuild with new heads and bearings, or just slap a cam in and run it.

I really don't care if I hit 350 that's just what I estimate base on a dozen other builds

I think 350 hp is very doable, but with diminishing possibility if the condition of the motor is poor.