Weighing my options

[matttahoe53]

Weighing my options (Building a 383)

I am looking to modify my 350 vortec or swap it to a 355 or 383. My goal with this truck is to increase low end torque due to the 33" tires this will not be a high revving engine. The exhaust has been upgraded to thorley tri-y's and 2.5" exhaust. I also have a CAI. With whatever modification I do I will probably upgrade to the 411 PCM. My rear differential has been upgraded to the 14 bolt sf with 3.73 gear ratio. At this time I do not want to change gears, the intake or fuel injectors (will swap out the poppets for the delphi unit though). I may change the intake down the road to the ramjet, but for my goals I don't thinks it is necessary. I also want to be able to run 87 octane fuel. I know a popular reply will be to do a 5.3 or 6.0 but I am not interested I don't to change things too radically, I am not that skilled and would not feel comfortable.

These are the options I am looking at:

1. Use my engine which only has about 20,000 miles and do a cam, rockers, springs, and a tune. This is the least expensive option, but I still will have to get into the engine and I am not 100% that this will be good enough.

2. This is a description of a 355 I could buy at a good price. Advantage is cost vs the 383. Will this have better fuel ecomy I am not sure. Also I am not sure that the effort to swap out my engine will be worth it both in terms of time and money.
New forged crank GM, new pink rods GM, new roller hot cam GM, new roller lifters, new GM full roller rocker's
New double roller timing chain and gears, new teflon coated bearings, new JE pistons, new chrome rings
New stainless steel valve's, has 1 piece rear main seal, vortec heads ported, flowed and CC'D
New billet splade main bearing, 4-bolt caps, line bored and honed, new high volume oil pump
New 6 quart corvette oil pan.

3. Is a new 383 built with a cast crank, dart heads, rockers, 210/215 cam. My concerns with this is it's the most expensive. Will compression be low enough to run 87? Will this be a complete gas pig? This should get me plenty of torque, but is it overkill?

So in short what would you guys recommend? Or am I just chasing my tale with this engine and should just leave well enough alone and except things for what the are?

 

[gd1]

What gears do you have? Might be worth looking into re-gearing the diffs before you drop money on building a new engine.

 

[superdave]

I'd hate to give up on a motor with only 20k miles. The mods you would make to it could be done much cheaper than either of your other options and with less work. The 355 is the same motor bored out .030. The 383 gives a few more horses probably, but at what cost?

 

[94Sierra4x4]

Well I mean they all weigh about the same.....

I say build the correct low-mileage Vortec 350.
411 PCM
Cam
Headers
Upgraded fuel system
Tune and enjoy

 

[matttahoe53]

What gears do you have? Might be worth looking into re-gearing the diffs before you drop money on building a new engine.

Gears are 3.73 and I don't want to go higher.

I'd hate to give up on a motor with only 20k miles. The mods you would make to it could be done much cheaper than either of your other options and with less work. The 355 is the same motor bored out .030. The 383 gives a few more horses probably, but at what cost?

What do you mean by cost? Money? Time? Fuel? Abuse to the transmission?

I understand that upgrading my engine is the cheapest option but will the upgrades make enough of a difference?

Well I mean they all weigh about the same.....

I say build the correct low-mileage Vortec 350.
411 PCM
Cam
Headers
Upgraded fuel system
Tune and enjoy

With the heads should I upgrade mine or switch to aluminum e-tecs? I assume you meant heads as I already upgraded to headers.

 

[superdave]

By cost, I mean that you can do the cam, springs, rockers, and tune for much less than $1000, if you do it yourself. Swapping in a 383 is going to run about $3500ish or more for an assembled engine. How fast do you want to spend?

 

[matttahoe53]

It's all a matter of can I spend $1500 now and be satisfied or $3000 over time and know I will be happy.

 

[matttahoe53]

Just ordered my PCM 411 today. This should be a good first step regardless of where I go from here.

 

[matttahoe53]

I have decided that I am going all in and building a 383. I have been doing a ton of reading on the best way to go about this. My problem thus far is trying to figure out what compression the engine will work reliably on with 87 octane fuel. I have searched the forum but can't come up with a consistent answer. So, if any of you guys that have done a 383 could respond and let me know what compression you are running that would be great. I feel like this is the first step I need to make a decision on before I can go forward and pick out all the necessary components. Also, with doing the PCM 411 swap will that allow for better engine management and allow me to use an otherwise higher compression?

 

[DGA1]

Stock L31 is 9.4:1 and it runs 87 just fine. Aim for the same and you should be alright. You are going with the roller block right?

I've been researching this too for a while now and am going back and forth between an LQ4 Gen III motor or a L31-383. Stock LQ4 will be about the same money, if not less, then building an 383. It will get you at least 300HP and 360 ft. lbs of torque. right from the get go. Then when you have some more cash and know what you want, get a bigger cam, headers, and a tune, and you'll be stearing down at about 400 HP and 430+ ft.lbs. of tq. with ease. More so if you go the L96 head route and Corvette intake, but then you'd have to change your accessory brackets too.

Why I suggest that is because of LSx engines being easier to work on, being able to put down more power with less cubes, and being overall more efficient. You can build a 383 from scratch for about the same money you'll put in the LQ4 with a swap and a few go fast bits and end up at the same power levels. LSx will be more efficient, but the 383 will be all freshly rebuilt. Your call really.