Thread: 377 Build

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377...yes higher revving...about that program, best out there at the time is Dyno Sim and its affiliates, get it at www.proracingsim.com it with the pro version is 199.00 or the decent version is 149.00 currently...it works very well and is very accurate. I don't mind high revving, but asking a question...have you ever driven a car that "only" makes power above 4000 rpm...the low down sucks for driveability BUT as you said, the car will be at the track most of the time anyway. Good luck, hope nothing frags on you with 20k invested or more!

Windowed: when roddeth cometh outeth the blocketh ateth the Pan raileth areath! YUP! Some notes, if you find an aluminum block that's damaged look it over real well. If the damage goes up into the cam bearing area, RUN! It's no good, can't be repaired (per Rodeck). The manufacture should be able to guide you to who repairs thier blocks. Standard deck height on small chevy is 9.025" that's an important starting number, because racers like to deck thier blocks. They usually run 2 piece intake maniflds so deck height is not as important to them. The deck height on my motor is 8.993" after resurfacing, to get my deck height back to almost normal I had the block "O" ringed and run a .062 copper head gasket. Good luck...

Builder,
I did put the car on the Dyno and was not pleased. The motor put out only 348 HP to the rear wheels. I am still working through that problem though. The cam is good to 76 to 7800 and the HP and Torque curve both peaked at only 5750. What I find strange is that both started to drop at the exact same time, so the engine is starving somewhere. The torque numbers were around 312 which is not good at all, but one thing, if you have a loose torque converter, which I have a 4500, you will get a lot lower torque numbers. A manual tranny car will always put up better numbers, even guys with auto's that have lock-up verters lock them up to get the higher torque numbers on the dyno. Our car club is having another dyno day in November and I hope to have made some changes by then and see if things are better.
I still have to do alot of tuning to figure out why the motor quits making power so early. I know it's not the heads and intake since I changed both and the car only went .14 faster at 11.54. I have the feeling it's in the jetting but don't have the time to get out to the track to play with it since I'm in the process of building a house right now. The good thing is when the house is finished I'll be only 20 minutes from the track where now I'm a little over an hour away.

Now remember you can slow the pistons down using the 400 crank by running longer rods if that's your concern. They have some pretty long rods available. Even if you go with the 350 crank I would go with a 6 inch rod. I just didn't have the money at the time to go with the longer rods when I built my 377, shoot didn't have the money for a good after market crank either. My compression is only at 11.41. To make it to the 600 hp range on a naturally asperated you would have to go quit a bit higher, then you will always have to run race fuel. I still run pump gas in my motor without any pinging at 36 degrees of total timing.
Good luck on your quest, I do like the 377 and it has a sound all it's own. I always get complimented on how good the motor sounds coming out of duel 3 inch flowmatsers.

Originally posted by techinspector1
Scott, let's go back to square one and I'll explain....
I have over 1,800 responses on this forum and a lot of them were to pimply-faced pencil-necked geeks who were going to spend multi-thousands of dollars and build the world's fastest car. When you get twenty of these dweebs in a row and then number 21, a guy named Scott comes along, how do you respond? That's why I asked if you were bench racing or if you really had the money to do this. I'm very tired of spinning my wheels wasting time on these guys. And it IS my time that I'm spending. By now, because of the posts which have passed, i believe you may be real and I will help you any way I can.

Hi Tech1,

I appreciate that. Hey, when I was 16 (in 1972), I weighed 200 lbs. There was no such thing as Nintendo and you couldn't see my neck! I was all about motorcycles back then.

I guess math just comes naturally for me and I can't understand anyone not being able to crunch some bore and stroke numbers to find a 377, that's why I made that statement about you not knowing where to start. Now, if we can start over at zero, I'll be easy to get along with if you will.

Math was never a struggle for me, and getting involved with CAD and CAM early in my professional life was a natural...never finished school, though. I owned an AutoCAD dealership in SoCal for 9 years and my customers were aerospace, defense, and architectural engineering types that I was teaching to use desktop CAD. Through using the software, it teaches you a lot about math. Pi * (radius squared) * height (stroke) is simple volume of any cylinder. So, a 377 can be made both ways then? The shorter stroke seems like the correct variant. Thank you... Just finished watching the Italian GP (1-Rubens, 2-Michael, for Ferrari again). Going flying now.

Originally posted by 1stGenCamaro
377...yes higher revving...about that program, best out there at the time is Dyno Sim and its affiliates, get it at www.proracingsim.com it with the pro version is 199.00 or the decent version is 149.00 currently...it works very well and is very accurate. I don't mind high revving, but asking a question...have you ever driven a car that "only" makes power above 4000 rpm...the low down sucks for driveability BUT as you said, the car will be at the track most of the time anyway. Good luck, hope nothing frags on you with 20k invested or more!

Seems to be the right software, that from ProRacing Sim. It's probably worth the investment... I have driven, but never owned, a rev-happy car. I stalled it a couple of times before getting the feel. It would be a pain in the @$$ in any city with traffic. Luckily, Reno has none to speak of. And, I hope to be driving through larger cities only to get where I am going...the track!

Haha! Yes, it would be ashame to torpedo an engine. I have been thinking that perhaps I should build a basic 350 before getting into exotic components for that very reason. Blowing up should be less expensive that way...a cheaper lesson. We'll see how I feel about it, once I have all of the components figured out. Ultimately, I may turn chicken (pragmatic) and drop the parts off at the local hot-rod house. But, at this stage, I don't see the task as insurmountable. Thanks for the link and the good wishes!

Originally posted by blwn31
Windowed: when roddeth cometh outeth the blocketh ateth the Pan raileth areath! YUP!

Haha...ouch! It hurts to even think about that!!! I hope that's not where "Blwn 31" comes from.

Some notes, if you find an aluminum block that's damaged look it over real well. If the damage goes up into the cam bearing area, RUN! It's no good, can't be repaired (per Rodeck). The manufacture should be able to guide you to who repairs thier blocks. Standard deck height on small chevy is 9.025" that's an important starting number, because racers like to deck thier blocks. They usually run 2 piece intake maniflds so deck height is not as important to them. The deck height on my motor is 8.993" after resurfacing, to get my deck height back to almost normal I had the block "O" ringed and run a .062 copper head gasket. Good luck...

You can bet I will crawl inside that block, if I find a used one. Probably even a new block should be tested. That's a great idea...to check with the manufacturer of the block regarding the repairs to their product. Sounds like you really scored on that deal. Thanks and I will be sure to post my results.

Originally posted by 73RS
Builder,
I did put the car on the Dyno and was not pleased. The motor put out only 348 HP to the rear wheels. I am still working through that problem though. The cam is good to 76 to 7800 and the HP and Torque curve both peaked at only 5750. What I find strange is that both started to drop at the exact same time, so the engine is starving somewhere. The torque numbers were around 312 which is not good at all, but one thing, if you have a loose torque converter, which I have a 4500, you will get a lot lower torque numbers. A manual tranny car will always put up better numbers, even guys with auto's that have lock-up verters lock them up to get the higher torque numbers on the dyno. Our car club is having another dyno day in November and I hope to have made some changes by then and see if things are better.
I still have to do alot of tuning to figure out why the motor quits making power so early. I know it's not the heads and intake since I changed both and the car only went .14 faster at 11.54. I have the feeling it's in the jetting but don't have the time to get out to the track to play with it since I'm in the process of building a house right now. The good thing is when the house is finished I'll be only 20 minutes from the track where now I'm a little over an hour away.

Nice! Not that I could know, but that's what I was thinking while reading...jetting, or ignition. BTW, spent the summer in White Castle, LA in 1974. She was one fine young lady!

Now remember you can slow the pistons down using the 400 crank by running longer rods if that's your concern. They have some pretty long rods available. Even if you go with the 350 crank I would go with a 6 inch rod. I just didn't have the money at the time to go with the longer rods when I built my 377, shoot didn't have the money for a good after market crank either. My compression is only at 11.41. To make it to the 600 hp range on a naturally asperated you would have to go quit a bit higher, then you will always have to run race fuel. I still run pump gas in my motor without any pinging at 36 degrees of total timing.

Now see? Just when I thought I was begining to understand...you go and say something like that! I can understand how a longer rod would change the compression ratio (lower), but, if the crank swing remains the same, doesn't the piston speed stay the same too; no matter the rod? It just moves up and down the same amount in a slightly different area of the cylinder? Or, should I be thinking about changing the throw on the 400 crank and going to the longer rods? That can't be it, can it?. That would change the displacement, right? Sorry for the rookie question, but that one escapes me!

Good luck on your quest, I do like the 377 and it has a sound all it's own. I always get complimented on how good the motor sounds coming out of duel 3 inch flowmatsers.

I can honestly say that I have never heard a 377 in person. But, I can't wait!!! Here are 3 videos of the GTR setting a 0-100mph-0 record (10.3 sec with a 377). Wish I was there to hear (see) it! Thanks and good luck with your project too...

http://www.ihp.com/ultima/Ultima-0-100-0.mpg (about 3.8MB)
http://www.ihp.com/ultima/Ultima-0-100-0-InCar.mpg (about 3.8MB)
http://www.ihp.com/ultima/Ultima-0-100-0-Rear.mpg (about 6.4MB)

Originally posted by Streets
Gee, LQQky here and they is in yer area too!!

http://www.ultimaclub.com/index-site.htm

http://www.automotiveforums.com/t3200.html

http://www.ultima-gtr.info/

http://www.kitcars.com/forums/topic.asp?TOPIC_ID=1569

Hey Streets,

Yup, got those links. The second one locks my browser up for some reason and it has to be TERMINATED.

In November, there are about 10 owners/builders getting together in Chicago. I will be there for sure.

Techchie,
Why will a longer rod not change the piston speed? If the speed isn't changing how is it staying at TDC longer?

Techie,
Your right on the mean piston speed not changing, overall the piston speed will average out no matter what rod length. What the longer rod does help is, the piston moves slower from 90 degrees btdc till 90 degrees atdc. This causes less mechnical stress due to lower instananeous velocity of the piston between those crank angles. The piston will accelerate away from TDC much more slowly than a short rod motor. The slower motion translates into a lower instantaneous volicity and hence lower stresses on the piston, piston pin and rod.
And of course the more widely know and understood fact that the longer rod will have a lower angle of the connecting rod with teh bore centerline during teh engine cycle. As you also listed.

Man I have to read and reread the effects the different rod lengths have on an engine many times, and each time understand a little more.
But shoot what can you expect from a chemical plant worker living in Louisiana for 36 years which is all but 3 years of his life.

Originally posted by techinspector1
Scott, a longer rod will not change the compression ratio or piston speed. What it will do is to "park" the piston at TDC and BDC a little longer than a short rod will. Smokey Yunick did tests all the way up to a rod/stroke ratio of 3:1 (for instance 2" stroke, 6" rod) and found more and more horsepower the longer the rod was. What happens is that when you park the piston at TDC with a longer rod, you are allowing more time for the mixture to burn and build pressure and therefore putting more force on the crankpin.

Ahh, okay. I can see how that works. That would lead me to believe that the same RPM deliveres the same piston travel distance, but, with the longer rods, the piston acceleration and deceleration rates are greater...and the piston actually travels faster in mid-stroke. If that's true, does that also mean that the intake can/should be opened a few degrees sooner and the exhaust closed a little later? Maybe durration needs to be shortened, with higher lift? Longer rod must also have an effect on port velocity...pretty much everything! Geezzz, that sure creates lots of questions!

Here's a piston speed calculator, you'll notice it says nothing about rod length.
http://www.thedirtforum.com/pistoncalc.htm

Well, at least I got those numbers right. I think I read somewhere that the upward limit for piston speed is between 4k and 5k feet per minute. So, I should be okay at 7.58k and 3.48" stroke. Okay, I think my mind will have a melt-down before my engine does!

Builder, heres the one of the articles that I got some good information on rod length. You can also search rod to stroke ratio on the net and find more info.
http://www.stahlheaders.com/Lit_Rod%20Length.htm.
Personally I haven't had a problem with the 5.7 inch rod using the 350 3.48 inch crank. Now I do know some folks who have put 5.7 inch rods in motors using the 3.75 inch crank out the side of the block or oil pan. This is probably due more to rod angle than anything, and the fact the guys were twisting these motors over 7000 rpm.

After reading one of the articles posted by Techie from Ron Iskedarian, I don't know what to think about all of this rod to stroke ratio stuff. It seems alot of information is based on opinions, and theory. One example is I have two books on building a small block chevy. One says that smaller lobe seperation cams are better for higher rpm and hurt you on low rpm while the other says the exact opposite. I have since seen opposing opinions on lobe seperation on the internet. Both points of view state supporting theorys, which is correct, or are they both correct?

Yep I know where Whitecastle is. That's about an hour from where I am living now. I am building a house about 20 minutes from there, don't know if you know where Gonzales is, it's right across from the Sunshine bridge from Whitecastle.

Keep doing what you are doing, asking questions and searching for info on the internet and build your own opinions and theorys.
Saw the videos site you posted on the car you are going to build, looks like one bad machine to me. Let us know how it's coming along as you go. I will let you know if I get my 377 to produce some more power and how I did it if it ever happens.

Originally posted by 73RS
Builder, heres the one of the articles that I got some good information on rod length. You can also search rod to stroke ratio on the net and find more info.
http://www.stahlheaders.com/Lit_Rod%20Length.htm.
Personally I haven't had a problem with the 5.7 inch rod using the 350 3.48 inch crank. Now I do know some folks who have put 5.7 inch rods in motors using the 3.75 inch crank out the side of the block or oil pan. This is probably due more to rod angle than anything, and the fact the guys were twisting these motors over 7000 rpm.

Yup, this looks like a real can-o-worms. Started reading that page and a couple of others. There are lots of dynamics here and it will definitely take me a while to understand all of the associated math.

After reading one of the articles posted by Techie from Ron Iskedarian, I don't know what to think about all of this rod to stroke ratio stuff. It seems alot of information is based on opinions, and theory. One example is I have two books on building a small block chevy. One says that smaller lobe seperation cams are better for higher rpm and hurt you on low rpm while the other says the exact opposite. I have since seen opposing opinions on lobe seperation on the internet. Both points of view state supporting theorys, which is correct, or are they both correct?

Or, are they both wrong? It's all very interesting. I remember pulling the engine apart on my first Techumse powered go-cart when I was about 12. Cleaned the sand out that some little kid put in while playing "gas station". Put it back together and it ran. Was hooked!

Yep I know where Whitecastle is. That's about an hour from where I am living now. I am building a house about 20 minutes from there, don't know if you know where Gonzales is, it's right across from the Sunshine bridge from Whitecastle.

Dude, that was 30 years ago. About the only two things I remember were the girl and the cottonmouths...and that I had a great time! I like that area, though. Lots of history and the people and all the food were great.

Keep doing what you are doing, asking questions and searching for info on the internet and build your own opinions and theorys.
Saw the videos site you posted on the car you are going to build, looks like one bad machine to me. Let us know how it's coming along as you go. I will let you know if I get my 377 to produce some more power and how I did it if it ever happens.

Good luck with that and I wll post my progress...probably on that ihp.com website and link it here.

Originally posted by techinspector1
If you were to build a relatively low-buck motor first, this would be a good starting point. This block will support 700 horsepower at 8,500 rpm's.http://www.sallee-chevrolet.com/Chev.../24502503.html

Hi Richard,

Considering the chance that my first build might not be exactly right, it could be wise to start with something less costly to replace should something go terribly wrong. Maybe the right thing to do is build a lower power iron block...just to get on the road, then work on the engine I really want down the road. I have spent a couple of hours on the Sallee website. Lots of goodies up there! They even sell the aluminum C5-R block.

Have you given any more thought to a centrifugal blower?

There was one guy who put a blower in his Ultima. It required chassis mods due to the length. The front of the engine is up against the "firewall", so there is very little room up there. However, it's not as good an option perhaps, but a turbo will fit under the lid. Just have to deal with the heat.

Anyway, my head is gonna explode. There is so much to know about building an engine. Like I said before, there's no replacement for experience!

Originally posted by Builder
Okay, that's what I thought...400 bored with a 350 crank. I asked because I know someone with a 377 in an Ultima. They beileve it's a bored 350 and are probably mistaken. Everything I have found on the Net says 400 with 350 crank.

To answer your question about money...money I got. Knowledge I want. Money to waste is another question. Not wasting money is how I got the money I have. You know. It's called saving your pennies. Duhhhh. I could buy the car completely built by the kit maker, if I wanted. The goal here is to learn and build something with my own two hands. I didn't come to this list for financial advice. I was looking for information about engines.

And apparently, you didn't comprehend my post very well. You suggest that I "don't even know how to start building a 377, much less how to pick the right parts to keep it together at 8,000 rpm's, so (I will) have to rely on a professional engine builder." What, really, is the intent or benefit in this bit of "info"? Not to be rude, but I will bet you there are many, many things that I can do that you might find quite impossible. And, learning how to build an engine is one of them.

Did you even notice that I put the right combination up there? FYI, I have a strong idea as to the other parts as well...Jesel, Brodix, Chapman, C&A... But, that's what I came to the list for. Aren't there engine builders on this list that share their knowledge? Seriously, my finances are really none of your business. You should be more concerned about the value of the content in the posts...especially your own post.

Time for you to be honest. Have you ever built an engine from the block up. If not, although I appreciate your links to information on the web and your cut-and-paste above, your really not going to contribute much. If so, why not share that knowledge?

Thanks!

I am currently building a 377 for my S-10 the parts I am using are .030 over 400 block 6" Eagle Rods, a Scat 9000 series crankshaft (which has the 400 main and 3.5" stroke so you do not have to use the spacer bearings) and a set of 12.5 compression pistons, there will be only mininimal grinding for clearance and the assembly must be balanced.
I think it is the better choice over a 383 and I think it would live a long time with proper maintance and keeping the RPM's below 7,000. I hope this combination puts my little S-10 down to 6.80's
So far it has ran 7.08 with a 355 in the eighth mile hopefully this little motor will prove worthy. Thanks feel free to E-Mail me with any questions.