Torqued Off

This thread will be about the final chapter in the story of getting a reliable, well-built and strong 400 SBC into my 77 Corvette. This is a follow-on thread from my “406 SBC Problems to Solve this Winter” thread. That sad story is now over, the thread closed, and the engine is gone.

Disclaimer – All my previous engine thread(s) were long, and full of many posts by individuals and trolls that chose to make personal attacks, or sarcastic responses, instead of providing useful technical content.These infractions are not permitted on this forum, and I will report to the moderators. So, save your nonsense if that is your intention. If the moderators don’t take care of it, I will close the thread and end my contributions to this forum permanently.

I have no intention of tolerating stupid egocentric personal attacks or one-liners by proclaimed “experts” that don’t provide technical explanations, and those that lack comprehension of anything but race car mentality.

If you choose to ignore this warning, you will be put on my Forum Ignore List, so I will not be seeing or reading your posts.

If you don’t want to follow the thread, then don’t follow the thread.

Otherwise, I welcome comments that are useful and respectful. I am always looking to learn the truth.

Since I am starting over, I needed to consider all the following possible options:

- Sell the Car and forget it. – Honestly, had the right person offered me the money I could have accepted…it would be gone. But I didn’t advertise it. It was the same state of mind that forced me to sell the 69 Corvette project, which is a sad loss. I would have built it into an awesome machine. But, despite all that has happened, I still love my 77. The wife loves the car too…and we enjoy it together. So no, not selling it…..yet.

- Rebuild the original L48 engine…sitting in an engine cradle in my basement. Over the years I have wondered if I would just have been happier taking that path, embracing the originality of the car, and being satisfied with the pathetic power the engine would make. If I did that, there is little point in trying to increase performance with the original components, because the gain is so little, it is not worth it to me. Adding aftermarket parts goes further down the endless rabbit hole, and it would still be a pathetic compromise. The real bottom line, now that I have experienced big power, I would never find a 185 HP L48 satisfying. Although I was seriously considering this option, it was the wife that talked me out of this option. Truth is, a Corvette deserves better than 185 HP. So…another no.

- Big Block - Since what I am really looking for is big block low RPM torque, it would make sense. The problem is, they are vastly more expensive, heavier, and tight in the engine compartment, and would require many different under-hood parts, different headers, etc. I considered a GM Performance 427 or 454 Big Block crate motor, but the numbers are not impressive for their excess cost. There is no less expensive way available to me that I would choose for me to get a quality big block. So, no on the big block option.

- Assembled SBC Crate Motor – While there are possibly some good options, this would be just another round of me trusting someone else to build an engine correctly and to my expectations. I’m done with that. And frankly, I am not impressed with any of the crate motors available. So, no…not interested in a crate motor.

- LS engine - I am not interested in ruining the character of the car. And I already own an LS powered 06 Corvette that is not that impressive.

- Last option - I build another big-inch SBC - Fact is that my plan for a big-inch SBC was the right plan from day one. I previously ran a well-built strong 350 SBC in this car, but I wanted more low-end torque / power. The solution was more displacement and a focused build on quality parts, durability, longevity, and built to deliver the closest thing to big block torque possible, within reasonable limits. I considered a 383, but if I was going to replace the 350, I wanted it to be a noticeable improvement if making the effort and spending the money. I also considered a 427 or bigger SBC, but for my intended purpose, there are too many compromises and too many things pushing limits in a SBC. The fact is 400 cubic inch is all I really need to meet my goals.

So, considering all the above options, this was my choice. I will build a new 400 SBC.

Torqued Off

The car….

In case you haven’t followed or know me, the engine is for my 77 Corvette. I did a full body off restoration on it about ten years ago, originally powered by a 350 that I assembled from a GM ZZ4 short block. I rebuilt the car and engine way better than Chevrolet did, with the best finishes and best components all around, to the highest standards, but still retaining the original character of the car. I drove it an average of 5000 miles a summer till I decided to get some more power with a big inch SBC



Driving Style and Purpose of Car

I enjoy spirited driving on the great back-country two lane roads of western Pennsylvania, shifting the 4-speed manual normally at 3000 RPM or less, never going past 4500 RPM or 60 mph. I don’t race on the street or on a track. All I wanted was a strong, torquey, and reliable engine to make the car accelerate as a Corvette should, within the range I drive, responsibly, on the street. I don’t participate in full RPM clutch drops, spinning tires, or any other egocentric / childish BS or abuse of the car or engine.

It's just me..enjoying the car..on the road.. doing what a Corvette was made for. This car, the way I built it, and because I built it, is THE most fun car I have ever driven, and is a dream come true. At 65 years old, I remember the 15-year-old me, who yearned for it then, but was not possible for some 40 years. Second only to owning and riding my Harley, owning and driving this car is the “place” where I am most happy in life.

In general….as you will see as I add posts to this thread, my plan for this build is to dial back the intensity of most of the choices from building a high RPM race engine, that I never wanted or asked for…..to a more mild engine that produces the best torque possible, from idle to mid-range RPM, and that is more focused on reliability, best combinations of parts, and less on intensity. And of course…. I would like it to be problem free. Millions of SBC engines over billions of miles prove that is a reasonable goal.

As I make decisions, and get that information formatted clearly, I will add posts, pictures, and will explain my reasons for every choice. As the build progresses, I will provide updates.

My hope is this thread ends with the engine achieving the goals I have for it, and the car back on the road.

Torqued Off

The History and Why it Matters

It is important to remember all the things that happened with the first two engine builds, as I consider the choices and decisions I make. Why? Because that is how I learned what not to do, and so is an essential part of making the decisions now. I guess in some sick way, the failures were useful…. but I would have been much happier to have put the first engine in the car, still in the car, running great and working fine.

The engine may have been salvaged, the third time, but it would have taken another almost complete rebuild to fix all the problems that I found and needed corrected properly. Ultimately there still would have been compromises that would affect the performance where I needed it, and the longevity of the engine. Just more money down the same hole. Absolutely NOT. I had ZERO interest in salvaging this engine. All I wanted was it out of my sight forever. And it was sold for $6000.

The main purpose of this thread is to document the build for my own sake…listing the reasons for every choice. Writing this is forcing me to consider and think out everything. Secondly, there are several members here that have become friends, and they have sent me PM’s expressing their interest in how I am proceeding to get the car back on the road….and I am posting all this for them as well. Maybe others will be interested and can gain something from it…. it’s a car forum.

I will list the components I chose and why., because everything has a purpose…and an application it is best designed for. It matters how the engine is to be used in your car and should be built for the real use of the car…the way YOU want to use it. Not to some extreme build for the biggest numbers, etc. so the builder can prove something to someone else or himself. Not everybody is racing on a track or on the street. If there was only one purpose and way to build an engine, they would all be the same, and there would not be thousands of different cams, lifters, pistons, crankshafts, etc.

I have spent the last several months researching and considering everything…. every single piece and every option, and I have reasons why I chose what I did.

OPINIONS

What I do know for sure is that for ANY given subject, someone has a complete 180 degree opposite opinion. I choose what makes sense to me, and is based on my technical explanation / foundation and reasoning at the time I made the decisions. My choices may be right or wrong, and I can change my mind with learning. Time will tell, but this time, I will do it my way.

And I have no doubt that somebody on this forum will think I chose poorly again……but unless you can explain your position, in complete detail that I can understand and agree with, I will do it my way, and YOU can refer to the Disclaimer I made in Post #1.

DorianC3

Hi Chief,

Your Winter thread was unbelievable. I only saw it a week or so ago. I could not blv the trials and tribulations you went through.

That being said, you are describing above exactly my goals are when it comes to how I like driving, what I expect from my Corvette, and what the engine should be like. I am addicted to 400s and am on my fourth build. A 400 is the scratch that relieves my itch for torque, power and drivability. I don't need anything more. Best of luck with this thread

68post

Any thought to the final iteration being a 421ci build vs. a 407 ?

Torqued Off

No, as I stated in Post #1, I considered engine displacements bigger than 406, but in my opinion, they are all pushing practical limits for my intended use and driving style on the street. This build is going to be only a 400, not a 406. On the first build I thought "might as well make it a 406....it will last me forever".....and then all the problems occurred. I don't think like that anymore.

Back when I was planning the first build, I started what became a very long thread, about the pros and cons of a big inch small block larger than a 406, and there was lots of input, and the final conclusion was that it was more compromise than gain, for me.

You need a reduced base circle cam for anything over 3.75 inch stroke, and as I said, I was not interested in boring out a brand new block any over 4.125 inch.....its just grinding away at new material in a new block, and further reducing the life of the engine by preventing future overbores with wear. The difference may be significant in the torque, but as I said, I don't need anything over 400 cubic inch. After boring away twice in the original engine,and needing a third bore to fix the problems....I decided to not throw away good money spent with the new block. Also, all the internal clearances get tighter on bigger displacements, requiring special parts and clearancing, compromised piston designs, piston wear increases with increased piston speed, etc.....everything about these engines just pushed all the limits further toward the extreme on an SBC that was never designed for it.

Bottom line, I am more interested in engine life than extracting a little more torque. I am confident 400 cubic inch will meet my needs.

wwiiavfan

Wow, heck of a post; heck of an experience you went thru. All I can say is good on you for not throwing in the towel completely on your Vette after going thru all that. You are a patient person.
I also share most of your outlook on performance goals, with the possible exception of not being impressed by later-model Vette performance. If there wasn’t so damn much stuff to change, I would consider an LS for my C3.
It’s a shame we’ve come to a place where, really, no one but ourselves can be trusted to do quality work. And arriving at a time when our age has sapped our energy and ambition for doing things ourselves.
Anyway, I wish you luck for this final chapter and hope it works out for you.

BKbroiler

OP - I'm going to offer advice here, so stop reading if you don't want any. None of this is an insult or personal attack in any way.
Unlike your 2 engine builders, I understand your goals with your engine performance. I don't share them, but I understand them.
A cost effective, expeditious way of building the engine you want (since it is almost March), would be the following:

Drag your old L48 out of the basement. Disassemble it and scrap everything except the block (2 bolt mains are all you need), connecting rods, oil pan and timing chain cover. No one will ever want that L48. Plan on building a 383. The extra 17 cubic inches are negligible considering the 383 and 400 have the same stroke. The 383 also simplifies the process somewhat.

Buy new forged pistons. Have block bored and honed to match pistons. Buy a CAST crank and have the L48 rods resized on the big end and get ARP bolts.

Buy a set of heads with medium size runners for best low/mid rpm response. Of course, match your heads and pistons for compression ratio, etc. Buy a hyd. roller cam with no more than 225/230 duration and 112 deg LSA. Match valve springs to cam specs.

Balance the rotating assembly. Use a new, stock type oil pump and weld the pickup on. Use your L48 oil pan. No scrapers, windage trays or any of that are needed at 4,500 rpm. Use the stock dip stick. Use a stock pcv valve set up.

Use ARP head bolts and main bolts and assemble it all. Use headers with 1 5/8 inch primary tubes. Use the stock timing chain cover with a double roller chain.

This engine will run forever and provide all the mid range power you could want. If not, you need a big block.

BTW, if you're still reading, I can recommend an excellent machine shop, in NJ. They can do all the required machine work accurately and professionally.

Torqued Off

Thanks BK......its not bad advice, and I like alot of what you recommended. I did mention the idea of using the original engine in Post #1. Unfortunately, despite me posting this thread today......I have already committed to a new short block, now sitting in my garage, and have bought new heads, cam etc....all of which I will reveal and detail over the next week or month.

I started planning this back in late November, and purposely avoided posting or asking for any advice on this forum. But, behind the scenes, I have been diligently working on the solution and my plan, all of which I want to do MY WAY, without any input from anyone here, or from any engine builders.

Why? The continuous string of contradictory and nonsensical opinions on engines on this and other forums has been very difficult for me to navigate, and in fact, is very frustrating. Between the wannabee racer boys, the self proclaimed experts, people who cannot comprehend anything but high RPM engines, and the obnoxious trolls, I just about gave up on all forums.

And so as a result.....I will not ask for advice again, and this thread is not about asking for advice, its just documenting what I am going to do.

This in no way is to ridcule your posting or your advice. I consider you one of my friends here, as you have always been understanding, and respectful. And again, your solution is a viable solution. The one part you mentioned was getting machine work done, and THAT is one of my obstacles, because I don't know ANYONE I trust to do that.....so that was the primary reason I did not choose that.

leigh1322

Well I tend to agree on the street engine choices mentioned above, torque is king.

I have driven a huge variety of cars. From 302DZ Z28s and Boss 302s. The rpm was impressive. But torque under 3500 rpm was sorely lacking. They were 15 sec cars in street form. So was our Fiero V6. Honestly no big deal. Felt much faster than they really were.

I grew up loving high strung and high revving engines, loved them, and have gradually learned that TQ rules.
I owned a 2 stroke Yamaha, 68 SS350 Camaro, Cosworth Vega, X11 Citation, two Taurus SHOs, and more, all revvers, all manuals. But all somewhat lacking in TQ.

My 1970 RS Z28 / LT-1 I owned and raced for 27 years. For most of that time I thought it was the cat's meow. ~400HP. The "perfect" car. Right?

Then over the years I drove a Baldwin Motion L88, an L71 427/435, a Buick 455 Stage 1, a Corvair with an Olds W-30 455, a 650HP low 10 sec 454 wheel-standing Chevelle drag car, and a 650HP 500 cube AC Cobra. Suddenly my LT-1 seemed rather "limited". I did not have to worry about rpm in any of those cars, at any time. They had Torque. My LT-1 did not have much.

So I sold it after 27 years and began my quest for my dream car with Torque. A 454 Corvette. A mild one would not do, so an LS6.
It's probably overkill....but I am somewhat concerned how streetable it will really be. So I cammed it a little "mild" not "wild"

I recently tuned a ZZ383 Camaro that ran 11s at Atco. With a mild & stone stock GM ZZ383. MIld stock cam really. It was a near perfect combination.
It has great TQ. Way more TQ than my LT-1. Only a little more power, but no waiting. Looks good, sounds great, runs good and has all the power you ever really need on the street. Maybe 425HP. It may have still had the OEM 222/230* GM cam, or perhaps one step hotter, because it ran so well.

My LT-1 felt like a high-strung race car, but the 383 just felt fast. Even with mild 336 gears and an auto, it will smoke the 245/60-15 BFGs as long as you want. All the way thru 1st and at least halfway thru 2nd. If you stomp it. By then I was at 70 mph and I let off. If you were a little more gentle on the throttle, it would mostly stay hooked in first and would definately hook in 2nd, and then it just flew. But it was still very docile and driveable. At any rpm, at any speed, it just flew. There was no need to wait for the rpm to build, it had all the Torque the tires could handle. It breaks the speed limit quickly and easily in a couple seconds, without going into endless wheel spin issues.
Anything more than that is just for noise and bragging rights. Street tires can't hold any more. Unless you intend to race.

A 425-450HP 383-400 is a terrific street choice. And fast. And somewhat "docile" . But will let you know it is there. 11sec street car? That's plenty fast. I'd say 450HP is the "sweet spot" for the street.

Anything at 500HP or over means compromises, and sometimes a lot of them. With more HP "Streetable" can quickly get lost and turn into "terrifying". I wish you all would have the chance to drive my buddy's 600HP L88 on the street, or try to, it really wasn't very streetable. Fun yes! Streetable, not so much. Just barely. Difficult to pull out from a stoplight, either stalls or lights 'em up, there was no in-between. No traction at all at WOT until 80 mph, and then 40 ft of rubber on the 140mph shift!

"Oh ****" !!

4-vettes

We are clearly not all that different. Although I lack the funds to do what you have done.
we both ride Harley's. Me, everyday. And I like my modern Harley with electronic cruise control and 4 valve heads, etc. Hardly a day I don't ride.
we both have 77 Corvette's. Mine sports EFI, power steering and Air-con. And.... runs hard at the local track. 6 thousand RPM shifts are normal for me. Air-con and all.
Yes, in some ways we are different.
My original engine just gave up about 7 years ago.
Still, original block. And 400 HP is easy.
I totally understand your quest for a high torque street engine. Totally doable and totally not like a drag engine.
Also totally doable with that stock block you have. But your mind is made up.
I'll watch this thread. And I'll try to shut up.

GordonR

Being your own chef in your own kitchen goes miles with me. I'm a Harley guy. Been to Bonneville three times, almost a dozen years competing in the Brute Horsepower Shootouts in Florida. Haven't crossed the road to a 4 valve yet. Still sticking it out with 2 valves and thumb screw for for now. "CorvettePassion" is definitely an appropriate handle for you. Good luck!

pspicci

Definitely looking forward to your updates on this thread. do you have a projected time line as far as when the engine will be done and in the car?
Pat

REELAV8R

Glad to see you're giving it another shot. Most people would have given up by now. I'll be looking forward to reading about your progress.

The knowledge that builders or someone building for you is not satisfactory came at a pretty high price tag.
It's unfortunate that to really get the quality you want you have to do it yourself.
I've always been a DIY guy and it sounds like you have as well. And the one time you hire a job out it turns to junk.
I understand just wanting a good product in the end, and being willing to pay the money to get it. But paying the money and not getting it, and then being left holding the bag...that's not acceptable.

leigh1322

OMF

I have a 400/406 in my car......I’m interested to see what choices you make given the engine parameters you want to run...trying hard not to make suggestions

OMF

Well it didn't take too long for this thread to go sideways.....

Just poking the bear for fun...

Torqued Off

You got that right, but I am not listening anyways. The comments and advice prove that some people don’t read my postings…they just start typing. One guy in particular I think has basic reading comprehension issues! Because he never fully answers questions OR responds to things not asked. I tune everything he says out anyway…so he is just wasting time on my threads. Him and I don’t operate our cars on the same planet.

GordonR

I would like to add the the build should start with the limitations it will have from the start. 1st is the intake manifold choice. Choosing heads will follow that choice based on port Id's and RPM limits. As an example how can anyone forget your intake manifold issues trying to fit it to your builders head choice as an after thought? . With all the work and money that was put into it one would have thought you should have been around 650 hp. 2nd is the fuel choice. A successful engine design starts with limitations as we cannot enjoy variable valve timing and exotic intake manifold designs. I see 3 basic choices when choosing what kind of engine to build. A. Maximum power for low to midrange rpm, high rpm suffers. B. Compromised power across an intake manifolds rpm design avg on low rpm semi strong on mid and avg power on top end. C. Soft on low rpm maximum power in the mid range and the higher rpms. Running full featured engine simulation programs It helps using brake mean efficiency averages (BMEP) in measuring an engines performance when designing over peak HP and TQ numbers in the confines of your RPM goals putting the best foot forward in making the maximum power for your build. I want as much power as I can possibly have within the confines of my limitations.

Tiger Joe

i know you said you made your mind up on a 400 sbc, but for the rpm range you drive in, IMO you would be way happier with a big block. I've read your other thread, im semi local to you (ive seen your parts for sale on marketplace), drive the same kinda roads you describe, and your driving style does not match the type of engine you build. its like have a foot long dong and only using the first 4" of it, doesn't make any sense.

I hope this time you find a local builder to work with you, there are still plenty of them in the PGH area.