Thoughts and opinions needed

[bruisedbanana79]

So my little 260hp 350 ate the thrust bearing and pumped all that bearing material through the engine. Its the standard 4 bolt main 2 pc rms block from GM. It is looking like it will need at minimum a new crank and a hone job on the cylinders or possibly an overbore. lets assume it is going to need the overbore I might as well stroke it out to a 383. Or do I just take the simple route and buy this Blueprint 383 short block with 1pc rms and roller cam with all forged internals? Blueprint 383 BP38321SP

If I go with the BP383 I will be topping it with a set of ported 441 iron heads that would drop the compression down to about 8.7:1. My concern is that the cam in this short block would be just a tad too large (Cam Type: Roller, Lift with 1.6 rockers .528 Intake .536 Exhaust, 221 Intake / 226 Exhaust duration @ .050 - 110 degree lobe separation). I would probably use 1.5 rockers to help pass smog and tame the cam for lower compression.

Here is where I need your help, I live in the "wonderful" state of California and still have to smog the car. Obviously I can keep a straight face at the smog station and say its just a measly 350. What would you do if you were in my shoes?

Long term plans will be to grab a set of AFR's in the next year or two to bump the compression back up and really like this thing sing. Car is mostly used on the street 95% of the time with the once a year trip to the drag strip just for fun. Budget is as cheap as possible - $5,000. Current setup- trans is a performance automatic TH350 rated to 550hp, 8.5" rear with 4.10's

I appreciate all the feedback possible.

 

[ck80]

So my little 260hp 350 ate the thrust bearing and pumped all that bearing material through the engine. Its the standard 4 bolt main 2 pc rms block from GM. It is looking like it will need at minimum a new crank and a hone job on the cylinders or possibly an overbore. lets assume it is going to need the overbore I might as well stroke it out to a 383. Or do I just take the simple route and buy this Blueprint 383 short block with 1pc rms and roller cam with all forged internals? Blueprint 383 BP38321SP

If I go with the BP383 I will be topping it with a set of ported 441 iron heads that would drop the compression down to about 8.7:1. My concern is that the cam in this short block would be just a tad too large (Cam Type: Roller, Lift with 1.6 rockers .528 Intake .536 Exhaust, 221 Intake / 226 Exhaust duration @ .050 - 110 degree lobe separation). I would probably use 1.5 rockers to help pass smog and tame the cam for lower compression.

Here is where I need your help, I live in the "wonderful" state of California and still have to smog the car. Obviously I can keep a straight face at the smog station and say its just a measly 350. What would you do if you were in my shoes?

Long term plans will be to grab a set of AFR's in the next year or two to bump the compression back up and really like this thing sing. Car is mostly used on the street 95% of the time with the once a year trip to the drag strip just for fun. Budget is as cheap as possible - $5,000. Current setup- trans is a performance automatic TH350 rated to 550hp, 8.5" rear with 4.10's

I appreciate all the feedback possible.

Here's the problem as I understand it. It's your appetite for risk, and concern over an illegal swap and the penalties that comes with it should you not apply for engine change and go through a referee.

If the block casting used on the 383 doesn't match what originally was approved as a direct replacement for an originally offered drivetrain -ie associates with a newer make/model then everything else on it needs to correspond from computer, fuel induction, emissions, etc.

So if they use a block that reads late 1990s c/k truck, they'll want the tbi, computer, etc etc or you fail visual before even getting to sniffer.

Would someone notice? That's the question I'd think.

 

[bruisedbanana79]

Here's the problem as I understand it. It's your appetite for risk, and concern over an illegal swap and the penalties that comes with it should you not apply for engine change and go through a referee.

If the block casting used on the 383 doesn't match what originally was approved as a direct replacement for an originally offered drivetrain -ie associates with a newer make/model then everything else on it needs to correspond from computer, fuel induction, emissions, etc.

So if they use a block that reads late 1990s c/k truck, they'll want the tbi, computer, etc etc or you fail visual before even getting to sniffer.

Would someone notice? That's the question I'd think.

Thank you for the response, you are correct if I get the guy who wants to inspect everything possible to try and fail me. Luckily I have a few smog shops that are pretty easy going when it comes to items like that, they pretty much pop the hood to make sure there isnt an LS in it and that the headers at least have an EO#. After that they only really care about if it burns clean out the exhaust.

I guess my question or questions for everyone here is:

will that BP cam be difficult to pass smog with if I have 76cc heads to lower the compression?

Second question would be do I build up my current motor that needs a rebuild or just grab the short block and call it a day?

 

[MontesbyE]

I came from California, had all enough of all that and I was out. The engine wont matter. They will be looking for the obvious CA smog goodies. The air pump, smog legal headers, catalytic convertor ect... dont worry about specs of the engine. No one can look at an engine and tell what the displacement is. Its their job to hook it up to the smog machine and run the diagnostic, not grill ya. PS take the simple route and ditch that old block that chunked its insides. You will always wonder about it.. Go with the BP engine.. Good luck to you

 

[64nailhead]

I'd be somewhat concerned about what pushed on crank hard enough to destroy my thrust bearing before I bought much of anything.

 

[bruisedbanana79]

I'd be somewhat concerned about what pushed on crank hard enough to destroy my thrust bearing before I bought much of anything.

That was my first thought as well. Two issues that came up during tear down. First and probably the culprit, i left the brass pilot bushing in the crank per gm’s instructions. The converter I am using has a little nipple on the front and just gently rested against the bushing and didn’t cause any issues during the install. Lesson learned big time! This was over four years ago and I have since learned a great deal.

second possible issue is the pressure side of the cooler lines had a decent kink in it which probably caused excess pressure in the converter and really exaggerated the first issue.

mind you I never checked for crank end play during the initial install or at all.

 

[Texas82GP]

I'd be somewhat concerned about what pushed on crank hard enough to destroy my thrust bearing before I bought much of anything.

^This.

The first thing to do is understand why the thrust bearing failed in an automatic transmission application. Is it possible the converter mounting flange to flex plate clearance is inadequate?

Next, what smog equipment are you currently running to pass the visual inspection? Are you running the smog pump, the EGR valve? The stock Quadrajet?

The reason I ask is that if you are getting by without that stuff, why not run Vortec heads?

Finally, I wouldn't buy the short block with a cam you think is a bit too big and then de-tune it with large chamber heads. You want to optimize your setup for what you need the car to do. That short block is too expensive if it isn't exactly what you need.

A 350 with a small cam and Vortec heads will make 350 HP and 400 ft. lbs.

How much of what you have smog wise and intake/carb/headers do you feel you need to keep to pass the visual smog inspection? Tell us that and more about what you have and we can start dialing in the recommendations.

 

[bruisedbanana79]

^This.

The first thing to do is understand why the thrust bearing failed in an automatic transmission application. Is it possible the converter mounting flange to flex plate clearance is inadequate?

Next, what smog equipment are you currently running to pass the visual inspection? Are you running the smog pump, the EGR valve? The stock Quadrajet?

The reason I ask is that if you are getting by without that stuff, why not run Vortec heads?

Finally, I wouldn't buy the short block with a cam you think is a bit too big and then de-tune it with large chamber heads. You want to optimize your setup for what you need the car to do. That short block is too expensive if it isn't exactly what you need.

A 350 with a small cam and Vortec heads will make 350 HP and 400 ft. lbs.

How much of what you have smog wise and intake/carb/headers do you feel you need to keep to pass the visual smog inspection? Tell us that and more about what you have and we can start dialing in the recommendations.

For smog equipment I have the following. Msd atomic throttle body, egr and smog legal headers without the air pump (surprisingly haven’t had anyone call me out yet for it and have passed 4 tests with them)

i would love to just throw the vortecs on and call it a day but that would remove the egr.

I am going to one of my local builders on Friday to find out his cost for just a simple over bore with a new crank and pistons. If that comes in cheap enough I’ll run this for now until fingers crossed they pass a bill that removes my need for smog.

I really would hate to invest a ton of money into a non roller block.

 

[Texas82GP]

For smog equipment I have the following. Msd atomic throttle body, egr and smog legal headers without the air pump (surprisingly haven’t had anyone call me out yet for it and have passed 4 tests with them)

i would love to just throw the vortecs on and call it a day but that would remove the egr.

I am going to one of my local builders on Friday to find out his cost for just a simple over bore with a new crank and pistons. If that comes in cheap enough I’ll run this for now until fingers crossed they pass a bill that removes my need for smog.

I really would hate to invest a ton of money into a non roller block.

Price it out. You can buy a new GM 265HP 350 for under $2900 including shipping.

Find out what machine work is necessary and cost. Put a new cast crank in it and a new set of pistons if an overbore is necessary. Look into putting in a retrofit roller cam if you are that concerned. They're expensive though. Consider a head upgrade that is compatible with the rest of your setup.

The key is to get the car back on the road quickly so you can enjoy it. I think if I was in your shoes I'd be looking at the 290HP 350.

Chevrolet Performance 19421178 - 350 290HP Base Crate Engine

Our most popular Chevrolet Performance Small Block Crate Engine delivers a broad torque curve at an exceptional value for a brand new 350ci engine. This 350ci crate engine is centered around the old L

sdparts.com

 

[melloelky]

unfortunately there's more con's than pro's here.the BP is a great upgrade for someone that doesn't have to reverse engineer it some in order to cross one's finger's to pass a smog etc etc.given your current zip code and how plentiful cranks/parts are for a sbc I'd spend a little now,knowing there's no question come smog time,back on the road and keep the motor upgrade on the back burner for a time or place where you can really utilize it all without issue and really do what you want.