Ability and Pros/Cons

[VorTecxas]

For the time being I'm just going to upgrade the spiders and throttle body (I just saw it in your mod thread/ just noticed that it was yours).

Good idea. Just keep it simple until you know for sure you can do more

 

[DGA1]

Since you seem to be itching to do something to the truck, the first course of action should be a 411 ECU and a good tune. Second, with a healthy cam, a bit of head work to handle the lift, and a good tune, you can max out the stock injector system somewhere around 380-400 Hp and same for torque at the fly wheel. Figure a grand for all of that. Then figure that the good ol' 4L60E is going to spit it's guts out, unless you have a 4L80E equiped truck, which will handle it if it's healthy.

In my mind a big block conversion is not worth it for the money and weight. You can easily get more power out of the L31, than a stock vortec 454, for about the same cash.

In the future, for the price of the marine intake you can get yourself a Edelbrock Ram style EFI vortec intake, that is a bolt on and has all the provisions except for EGR. The stock L31 throttle boddy will bolt on too. You'll have to figure out the injectors you'd like, the fuel pressure regulator, and fuel lines. Besides an ECU and the tune to run the stuff, you are set.

http://www.summitracing.com/parts/edl-7138/overview/make/chevrolet

Fuel Rails

http://www.summitracing.com/parts/edl-3627

 

[VorTecxas]

In my mind a big block conversion is not worth it for the money and weight. You can easily get more power out of the L31, than a stock vortec 454, for about the same cash.

Unless you can buy the truck it's in, yank it out, and make more off parting it out than you paid for it, which turns into a pretty good profit AND you now have a full big block setup that you technically got paid to get

Which coincidentally, is what I got lucky enough to do. Granted, not everyone can find deals like that when they need to, but you also have to know where to look for parts or vehicles. And patience is a BIG part of saving money. If you have time, use it, look for the best deal, you don't have to run to Summit or Jegs or LMC right away. Now, I apologize in advance for the long post, but I have had to make this point many times to people who bring up the same issue.

Weight is really not that big of a difference stock for stock. A fully dressed 350 weighs about 575lbs, give or take, and a fully dressed 454 weighs about 650 lbs. The 4L60E is 163 lbs, and the 4L80E is 295 lbs. (Two wheel drive). So, 350 and trans = 738lbs, and 454 and trans = 945lbs. A 207 lb difference. So about the same as your best friend riding shotgun...or 2 babes in bikinis, your choice.

Let's look at power to weight. Since most people are concerned with horsepower (don't know why, torque is more important in these trucks), we'll start with that.

Vortec 350 = 255HP = .35HP per pound (engine/trans only, not truck)
Vortec 454 = 290HP = .31HP per pound

350 wins that one. But, not by much. You really think you'll notice .04HP in the seat of your pants? And we still have ease of upgrade to talk about. Let's look at torque

Vortec 350 = 330ft-lbs = .45ft-lbs per pound
Vortec 454 = 410ft-lbs = .43ft-lbs per pound

350 also wins that one. Starting to look in the 350's favor. Now you have to consider where that power comes in. Since horsepower is for maintaining your speed/velocity and torque is what gets you there, we'll focus on torque. Since that's what you "feel" when you mash the gas from a stop.

350 = 330@2800RPM
454 = 410@3200RPM

Since it's hard to judge two different RPMs, we'll bring the 454 down to 2800RPM (since we are talking peak numbers, you can't bring the 350 up to 3200 to compare), where it makes approx 360 lbs (rough equation - torque/peakRPMxdesiredRPM - not exactly dead-on accurate, but close enough, I've backed it up with numbers before on other builds). So, your 350 has only 330ft-lbs up to 2800RPM to push your truck up to speed, where your 454 has 360ft-lbs at that same RPM, and also has another 400 RPM until it's peak, which is still another 80lbs more than the smallblock. Now, keeping the speed - horsepower.

350 = 255@4600
454 = 290@4000

Bringing the 350 down to 4000 RPM, you get approx 222HP, and you only have about 33 more ponies for another 600RPM. The 454 reached that number (255) at about 3500RPM, and has approx 35 more to give to it's peak at 4000. Not to mention the 454 will wind higher (I had the 3/4 ton I pulled the engine out of above the 5500 mark many times. Yes, the governor was tuned out) And honestly, in a DD, you'll rarely see those RPMs constantly, unless you're passing or getting on the highway. Or just abusing the crap out of your truck. Which I do. A lot.

But, now you have to compare what you can do to upgrade them. For time's (and my fingers) sake, I'm only sticking to the very basic upgrades

Fuel Injection
350 - Spider injection, injectors not replaceable, have to buy an intake to upgrade (meaning higher flow, not the "upgraded" spider, which still only flows 19lbs/hr). Using the link you provided, we will go with that price. $409.95. But now you also have to buy injector rails, injectors, an adapter harness (or make your own), gaskets, etc etc. AND make all of your sensors work, etc, etc. I have a "friend" (more like a guy I just know that I've helped before) who did a very similar upgrade. He bought all of his parts new and it cost him right around $5,000 for parts and a tune. He did the labor himself.

454 - Multi port injection (19lbs/hr). You can Throw in a set of 28lb LS1 injectors (I got a full set rebuilt, tested, and flow matched for $95 shipped. The factory tune will run them fine) and a new pressure regulator (the stock ones are crap), which was purchased for $39.95. Or any EV1 style injector, which are cheap and used in just about everything.

Headers

350 - Have to use Vortec headers if you want to keep your EGR, or you can use TBI headers, delete the EGR, and have it tuned out if the CEL bothers you. Older headers won't work since the bolt pattern is different. Vortec headers run about $225 on the cheap end. TBI headers are about $185

454 - Have to use Vortec headers to run your EGR, or any truck headers for round port exhaust from about '65-'01. Leaves a lot of options. I got a pair of ceramic coated mid-lengths for a '78 3/4 ton for $125. Fit perfect, and I'm having my EGR tuned out.

Heads

350 - Must use Vortec heads (yes, this includes all aftermarket castings as well) to use MPFI

454 - Pick a round port head from '65-'01, any casting. They all fit the stock intake and exhaust. Not to mention the older heads can handle much more cam without being cut.

Cam

They're pretty much even on variety and price. Without having to mess with your tune, you can get an LT1 or LT4 cam for the 350, and a Mercruiser or ZZ502 cam for the 454.

For my 454 conversion I have purchased (these are upgrades, does not include my tune-up parts - wires, plugs, etc) a cam (roller, since factory is also roller, reusing my lifters), LS1 injectors, adjustable fuel pressure regulator, fully loaded billet distributor (have to use with the billet cam), and ceramic coated headers, all for a total of a hair under $500. And I'm not done. Still looking at heads and other this-and-that's.

Sorry I ran on for awhile. I have a lot more to input, but I just needed to put the basics here. Basically my argument is this - if you have an opportunity to pick up an L29 setup for $1200 or less, you're already doing better than upgrading your 350 (also consider you can sell your 350 setup, which brings the cost of the big block down, a good L31 and 4L60E can easily bring $600-$1000 in my area, depending on mileage and appearance of condition). Don't get me wrong, I LOVE my 350, but for performance the L31 is not financially efficient to upgrade compared to the big block, and doesn't weigh THAT much more. If you have a toolbox in your truck (with tools in it), or carry a buddy around a lot, you already weigh more than an equivalent truck with a big block and no tools/extra person.

That's my .02

 

[VorTecxas]

Since you seem to be itching to do something to the truck, the first course of action should be a 411 ECU and a good tune. Second, with a healthy cam, a bit of head work to handle the lift, and a good tune, you can max out the stock injector system somewhere around 380-400 Hp and same for torque at the fly wheel. Figure a grand for all of that. Then figure that the good ol' 4L60E is going to spit it's guts out, unless you have a 4L80E equiped truck, which will handle it if it's healthy.

Good advice, pretty much what I've been trying to get across throughout this whole thread

 

[DGA1]

Ha ha ha ha...solid breakdown man! I've just never been too big of a BBC man myself. I can't argue much though, just add that which ever way you go, you are working with a SBC, or a BBC, meaning each have more ways to make power than you can think of.

Personally I'm going the route I described above, but with a .030 over bore and a stroker crank to end up at 383 cubes. A cheap build mind you and one mainly used for hauling my go fast toys to the race track and work around the house.

 

[VorTecxas]

I considered a stroker, but when this 454 fell in my lap it was a no-brainer.

I wasn't trying to be a jerk (for lack of a stronger term, since I can't type what I really wanted to) about it, I just figured that's what these forums are for right? To discuss and debate differing opinion to end up with a better result overall.

On that note, anyone still want to argue the "big block is too much weight" assessment? Hell, we'll throw in full truck weight and what all can affect that as well, just for fun.

 

[Parentnoia]

I considered a stroker, but when this 454 fell in my lap it was a no-brainer.

I wasn't trying to be a jerk (for lack of a stronger term, since I can't type what I really wanted to) about it, I just figured that's what these forums are for right? To discuss and debate differing opinion to end up with a better result overall.

On that note, anyone still want to argue the "big block is too much weight" assessment? Hell, we'll throw in full truck weight and what all can affect that as well, just for fun.

Weight can always be remedied if you ask me.

 

[VorTecxas]

Yes it can

 

[Parentnoia]

Little bit off topic, but my truck did me proud tonight. Neighbor managed to slide his car down the hill between our yards and got stuck in the mud (it's been raining for over 24 hours) so I had to pull him out. Good thing I'm a night owl. He almost hit our house and if he had hit the house, it would have been my fiancee and I's room.

 

[stroker52]

this topic is why i like the LS motors so much... ive built 350's 406's 434's big blocks so on and so on but i will give them all up for a LS motor...