71 350 Conv. Resto. Keep matching #'s 350 or Get 455?

I think I'll get one of those Tomahawk engines then: all aluminum, massive displacement, and with tuning techniques permitting it to achieve 30 mpg that will pretty much be the best of all worlds. Why didn't I think of this sooner?

*looks at bank account* oh yeah! that's why. :grin:


I guess when you're looking out from the deck of your 5th yacht onto your beachfront property, thinking which house do you want to live in this season, your choices become a little bit easier on which path to choose when deciding on a performance package for your umpteenth vehicle.


You guys have fun and always be safe. :beers2:

 

If that's a reference to post #52 then I would have to totally agree with you. :grin:

"Stock" engine builds suck because of the "stock" type junk replacement pistons available for that kind of build.(period)

Use of aftermarket style pistons whichever platform you decide to utilize and you'll be 10 to 25% higher in power without the addition of anything else! With the BBB aftermarket pistons with a quench pad will make the factory style closed chamber heads more useful to allow more compression without detonation than a factory style full diameter dished piston. Buick back in the day when they were decreasing compression figured out that with the full diameter dish pistons that the chamber style didn't really matter so they changed to an open chamber design the last 2 years of production. Unfortunately they didn't go the other way and utilized the closed chambers with a quench pad on the pistons to bring power up while keeping detonation in check while still being able to run the BBB 455 on the new cat pee gasoline the EPA wanted cars to run on.

Aftermarket rods are a good choice as well, even though the BBB 455 rods are plenty strong with the addition of ARP bolts, you may run into problems in at least one of the rods trying to recondition them and may need to find a spare or 3 because of how out of alignment they can become with the new ARP bolts making them unusable.


Rods from different applications can be made to work for stroker builds. For example the very affordable nascar take out rods for sbb 350 engines to use when building a stroker, or there are a couple off the shelf choices that would work as well. But would cost and weigh more and would be lessor rods than a nascar take out rods that costs over $2,000 new can be bought used for around a 90% discount plus or minus, that being slightly used still have plenty of life left in them for a street application or even a 10 second drag race app would be nothing compared to hours at a time abuse they endure in oval track racing. Usually the nascar take out rods get changed after just one race and sometimes get replaced after being just ran on the dyno once!

Then there are a couple choices for the BBB, for example BBC rods for a .050" more stroke to make a 470, the Ford 5.4L rods for .160" more stroke to make a 482 BBB among others that can be made to work in a BBB.


Of coarse the AutoTec line of pistons for the big and small block Buicks make it easy to use the rods from a different app because of how those pistons are customizable for the same price sold as a piston and ring kit that are far superior than the crappy "stock" style pistons available with their antiquated heavy design with rings way thicker than they need to be, creating more frictional drag than the updated designs used in modern pistons. Are these the best pistons to use, depends on what is being built. The 4032 forged material they are made from aren't as good for high boost or huge shots of N02 but are a great lighter than factory with modern rings great for N/A engines up to 12.5:1 compression.

If lots of boost is wanted or high compression with a huge shot of N02 is wanted then a 2618 forged piston is the way to go, which will cost more than the above pistons.


Making a 380 sbb stroker would be the least expensive with the result of big block torque and being able to still rev like a small block to 7,500 RPM!

That's enough for now, good luck with whatever engine platform you choose.






Derek

 

Spoke with one of the more reputable engine builders in my area today.

To have the stock 350 engine in my '71 Corvette rebuilt to stock specs would cost $4K.

That's with me pulling it out, bringing it to him, and me putting it back in.

Warranty is only 6mos/6K miles, because I'm the one initially starting it and breaking it in.

For an additional $1K, he'll break it in and tune it on the Dyno.

I think I'm staring to understand why crate engines are so popular.

Thanks

 

Much like Larry, my big lumbering Big Orange turd ran 11.58 at 114 with AC and all the goodies 4150lbs, 1.25 front sway, stock springs,shocks,bushings, nice stereo and got an EASY 15MPG with its 3.31 gears and 28 in tires. Drove it up and down "Dragons Tail" and I40 and 26 thru the Smokey Mountains at speeds not many people will try in old school muscle with stock suspension,... And this is why me and most everyone else builds 455's

 

^^^ Good post.

 

Big displacement makes everything easier, including well sorted, easy to drive, decent mileage combinations.
It isn't huge $$ or secret tuning skills. Keep things simple.
My learning curve started young when there wasn't decent $$ to play with.

 

I sooooooo want to go with a SBB stroker, a tremec and deep gears. After my (stockish) BBB is built that may be my next project. It's all about the bank account and what I can get away with.

 

Well, building your own engine IMO is the best part of this hobby. From the start doing the research of what needs to be done to make the engine of choice to perform the way you want it to run, to the satisfaction of turning the key and starting it for the first time breathing new life in the engine you assembled with you own 2 hands. Then tuning it to go faster and faster, and upgrading the car to handle the extra power of the engine that you built with your own 2 hands.

So if you take the plunge and build an engine yourself it looks from the pricing you wrote down there would be WAY more $$ to spend on cool parts like roller cams, roller rockers, forged pistons and nice aftermarket rods, aluminum heads and intakes to mention just a few cool things that can be added in the budget if you tackled the job yourself!


For example you could build a kickass sbb stroker for just under $3,000 IIRC(doing the assembly work yourself of coarse) and for just under $1,000 you can add FiTech self leaning EFI that most novice installers can make work flawlessly the way they're designed to work;

http://fitechefi.com/

So no need to have the engine dyno tuned with a self learning EFI system! See what you can do getting away from "stock" junk rebuilds. You know, using non-"stock" internal components helps build a better engine without anyone able to see the inside of that engine, so the outside still will look factory.(its to bad you didn't build a sbc 383 for your Corvette, it would of still looked the same on the outside)


The downside to doing it yourself would be no warranty, but the $$ you save doing it yourself can buy you a roller cam and lifters which means you don't have to break in the cam where most failures happen. But if there are issues you know that engine inside and out so repairing it wouldn't be such a big deal if by the small chance something does go wrong.

With a website like v8buick.com doing your first build with the guidance from the knowledgeable people on this site makes it a WHOLE lot easier than back in the day when all I had was a Chilton repair manual. We can guide you from start to finish with your build, I can even send you my phone number if in you're interested in the sbb stroker option to fill you in on a few of the details. I think I have a sbb stroker build plan written done somewhere if you're interested that as well or one of the BBB stroker builds too.






Derek

 

Derek-Thank you for the encouragement, and generous offer of your guidance.

I haven't yet rebuilt the engines on any of my cars. In my above post regarding my '71 Corvette, I was just relaying information which I had gathered today. I did get a little sticker shock at the $4K quote for a stock rebuild (with me doing all the heavy lifting), but I guess that's what the market commands in my area (Boston). However, people pay it everyday, and don't blink an eye. Like yourself, I find a 383 stroker dressed up like a bone-stock 350 to be very appealing.

I have far more time than money, so it's in my best interest to do as much as I can myself. And, as much as I complain when parts don't fit, things don't work, etc., it's the challenge and satisfaction I get with each little mechanical victory that keeps me coming back here. If I just wanted to change oil and drive, I would sell all my old dinosaurs and get a Viper, or some nonsense.

I was feeling so overwhelmed this year with the endless stream of big and small repairs for my '71 GS, that I almost threw in the towel. If not for the encouragement of several key board members here (you know who you are), I can say with complete certainty that my car would be in the classified section of this Forum right now.

With regard to my GS, there's not too much more I can do unless I want go for The Full Monty (frame off). I'm getting toward the point where I can hopefully start enjoying my car, while not having an ongoing mental 'to-do' list running in my head as I drive.

All my toys hibernate starting December 1st. My repair list for spring 2017 is as follows:

Daves HEI conversion
Internally regulated alternator
Some type of steering box conversion
Fix a weeping TH350 tailshaft
Complete interior resto (buckets/console, tilt, tach, gauges, Rally wheel, stereo)

I already have most of the parts for the above mentioned repairs. Feel free to comment if you'd like to get the wheels turning.

Thanks, once more.

 

I'm certainly not disagreeing. I love BBB's too. I just wanted to offer up an alternative POV to weigh in with everything else.

It can sound like I'm cheering for one or the other when I type up comments regarding something, but the reality is everything has its pros and cons.

Everything is preference in the end. To say 15 (or even 18) MPG is 'good' is definitely subjective. Good for that type of car, certainly, but not good when you consider a 350 can get well over 22-25 with a similar setup. It may not dip into the 11's, but it will definitely have better cornering and stopping performance. It's all according to what you value most in a performance car, and what you intend on using it for.

 

Steve Caruso says his 350 combination that runs mid 13's @100 with a 3.42 rear going down the interstate @70 MPH gets about 22 MPG (IIR), and that's through the iron manifolds, since he keeps his car in the pure stock class. Simply adding in headers and tuning it with those would net another 3-5 MPG, no doubt.

My '69 Electra 4 door land yacht got 18-20 MPG when I babied it, and it had the factory assembled 430.

My '68 Lesabre with the 350-4 got around 22-25 MPG when I babied it, and on extended trips @100 MPH, it got 17 MPG.

After I put in the 455, gas mileage dropped to 12-14 average (no headers), and it handled like a boat. Admittedly, better suspension would have improved this.

I think a lot of people would be surprised at how well these engines (even the big blocks) can sip gas when they're not choked down, but 105 more cubes is going to be thirstier as a rule.

 

That's only if you are running at the similar rpm with the same manifold vacuum reading. If you are able to observe a higher vacuum at cruise, then less displacement or mass is passing through.

Not trying to throw stones, only noting that several others have seen the opposite of the 'rule'.
Superior Buick engineering.

 

This won't offset the massive CID difference most of the time, given similar engine characteristics between them. As with any 'rule', there will always be exceptions. A 455 could get better mileage than a 350, but odds are not in its favor when both engines are tuned optimally and both have similar build characteristics.

Other factors also play a role, such as vehicle weight, gearing, throttle position needed for cruising, etc.

You could get a big block to get 30 mpg if going downhill for miles on end and a 350 to get 10 mpg if the vehicle was underpowered, towing, uphill grades, etc. etc. etc.

There are many varying factors to consider, but when you put them side-by-side in a fair, non-biased comparison, the rule pretty much applies.

Superior Buick engineering is applicable to both engines in this comparison.

I've heard of low comp stock 455's getting well over 20 MPG in very light cars, such as G body Regals, when the OEM gearing is retained; I've also heard of low comp stock 350-2's getting 10-12 MPG in those huge B and C body cars in the early-mid 70's.

Again, I agree, and it can be summed up as: it depends.

There's no getting around the weight differences and placement though, and while it won't matter much for 1/4 mile drag queens, it would matter more for someone who wants to make it more street friendly with windy back roads in mind, who doesn't really care if someone else has something more powerful. That's the funny thing about this whole conversation is that people want more and more and there's never enough power on how fast you want to get killed, when they forget that no matter how much you have, someone, somewhere else out there will always have more.

I say be happy with what you have and have fun with whatever tickles your pickle. Have a goal in mind, achieve it, and leave well enough alone. Set another goal, achieve that, and so on and so forth.

 

I wasn't looking to split hairs or elevate more tangents...I simply see equal to better mileage from the big ones.
If your experiences show otherwise, great. Mine do not.

 

I wrestled with the same thoughts. when I first took over ownership of the car I immediately started looking for a 455 to swap, there was no question in my mind.

As I drove the car and really began enjoying it I changed my mind. I like tinkering anyway so I decided to see what I could do with the stock 350. there is a sense of satisfaction in making something good, better. mine is a 78,000 mile car. every winter I do some project. first year was suspension, poly bushings, springs and shocks. Next year was electronic ignition. last year was four barrel intake and carb from Ken. this summer I purchased a factory GS 3.42 posi rear from a member, I think that will be the biggest seat of the pants improvement to date.

Future plans include cam, headers, and converter swap. It is cool to take it out every spring and feel the difference.

Personally I don't give a **** about numbers matching, its not a Hemi Cuda or a high dollar GSX. I make the car the way I like it.

 

Come on now, you know this is exactly the type of dialogue you get into, so saying you weren't trying to do this or that looks kinda like backpedaling; now toss in 'experiences' for good measure, hoping the extra 1,000 engines you've built will trump my own and it looks like a nice solid rebuttal.

I guess there's no point in the 350 even existing at all then. There is absolutely no bias toward the bigger is better and wanting more and more whatsoever.

It's ok, I'm just tryin to tease ya a bit. All good-natured.

So what was it again, 28 mpg out of a 450+ CID, 550 hp engine? No wonder you're biased with results like that!

How much did it cost to achieve those results, and were those all on the same tune/dyno run?

One last question: did the Buick 350 you built along side this amazing big block even compare to the 'big one' with gas mileage? How close was it, and/or how much better gas mileage did the biggun get?

I just might be sold on big blocks forever if there are zero cons to them and the 350 has no pros by comparison. Seriously.

My experiences show different results, but maybe I've been doing things all wrong? I'm willing to learn. :TU:

 

Lol.

 

<3 :grin:

 

In all seriousness, I'm not disagreeing. Just saying it depends.

As in a previous post, I gave a few examples of now this could happen, but after thinking about it a little while, I wanted to add to it some.

As you previously summed it up, as long as the RPMs are the same and there's less throttle needed for cruising (better intake vacuum), the big block could get equal or better mileage. Not likely, but could. At the very least, it would close the difference gap between the two.

IF the horsepower levels were similar, the 455 being built mild-moderate and the 350 built fairly radical, then the odds are in the 455's favor. HP is HP, no matter how you achieve it, and the 350 would need more RPMs to move as much air/fuel as the biggun at lower RPMs. This would cause the 350 to have poor vacuum compared to the 455, and wouldn't be nearly as efficient at lower RPMs for 'normal' cruising---but this type of setup wouldn't really be aimed at this sort of activity so much, so this becomes an apples/oranges comparison.

IF the horsepower levels were not similar, both engines being built mild-moderate, then odds are heavily in the 350's favor, providing the car it was in didn't weigh too much, thereby creating a need for more throttle during cruising and acceleration under normal driving circumstances. The 350 would obviously not be as fast, but would certainly get better gas mileage this way.

This is just gas mileage-gas mileage comparison, and doesn't consider the weight savings and better weight location, if that matters depending on what one intended on using the car for.

But what about the torque difference you ask? Very good question. In keeping with the theme of 'there IS such a thing as too much', torque moves the weight, and horsepower is how fast it moves that weight. If the torque is sufficient for the power-weight ratio of the car, less torque isn't necessarily a bad thing, especially when considering suspension, traction, and the structural integrity of the componentry.

So there really are pros and cons, less so if one or more of the aforementioned pros/cons didn't matter to the owner/operator.

Not really off topic or even a tangent, as this pertains directly to a 350 vs 455 comparison, though there are more items to list (such as cost, fitment, parts availability, engine core availability, etc. etc. where applicable).

One should make a list of the things they want out of the car (performance (power desired), gas mileage, handling, matching numbers, etc.), set the goal(s) and go from there.

These are my own thoughts, and even though I may read 'too much internetz', we can all learn how to discard nonsense and assimilate factual information for better personal enrichment.

I have my own personal experience, and while it may not be equal to or greater than many experienced professionals here on the boards, I have tidbits of info I like to share for an alternative point of view.

In the end, I'm just the peanut gallery.

Thanks for reading.

 

Dont want to hijack the thread, but what if you have a numbers matching Skylark, not a GS or convertible is the answer the same? Original or modify?