short stroking high revving v8

[Guest Anonymous]

WOO that link kicks ASS

 

there is hope afterall

[Mudge]

Stock LT1's and LT4's rev quite freely to 6300 RPM. Just need to open up the breathing, maybe some roller rockers.

 

Yep, the LT1 wont breath much at high RPM and it doesn't have the cam for it, past 6200/6300 roller rockers are a "must" and thats why the LT4 got em. I ran mine to 7k with no problems.

[Mudge]

I dont want a motor that revs to 10k

 

I want something that doesnt start to fade after about 5500 rpm.

 

Then your looking for love in all the wrong places You need to cam it' date=' and get some headers/intake work that will let it breath. If you put a torquey cam in there then dont expect your RV to pull to 7k RPM and like it, power will fall off with a small cam at high RPM thats just how it goes. High RPM V8s will go lump-lump at idle if you know what I mean. I ran a 234/246-110 and it ran great to 7k, and with 3.42s (T56) still had enough balls down low to daily drive without slipping the clutch like nuts. Would have had even more impressive timing work if I had access to 92 or better octane, down low had to be a little conservative with 91 MTBE.

 

[/supraexcuse']

 

Where do you want peak RPM to be? That will be one thing deciding what cam to go with, and if headwork should be done or not, yada yada.

[Guest Anonymous]

I dont want a motor that revs to 10k

 

I want something that doesnt start to fade after about 5500 rpm.

 

Then your looking for love in all the wrong places You need to cam it' date=' and get some headers/intake work that will let it breath. If you put a torquey cam in there then dont expect your RV to pull to 7k RPM and like it, power will fall off with a small cam at high RPM thats just how it goes. High RPM V8s will go lump-lump at idle if you know what I mean. I ran a 234/246-110 and it ran great to 7k, and with 3.42s (T56) still had enough balls down low to daily drive without slipping the clutch like nuts. Would have had even more impressive timing work if I had access to 92 or better octane, down low had to be a little conservative with 91 MTBE.

 

[/supraexcuse']

 

Where do you want peak RPM to be? That will be one thing deciding what cam to go with, and if headwork should be done or not, yada yada.

 

peak RPM? or peak HP?

 

If you are talking about HP im thinking around 6k maybe 6.5K

 

RPM i dont know yet.

[Mudge]

Ok, your looking at anything from approximately 214 on the intake to 230ish, if on a 112 LSA. Cam MFG will give an approximation of running range, with the high number being quoted for peak HP, not shift point.

[DavyZ]

I think this is the build article on the 377:

 

http://www.airflowresearch.com/articles/article03/A3-P1.htm

 

Davy

[Guest Anonymous]

I think you are kidding your self if you think that 234 246 cam is making power to 7000. I hope you have ARP rod bolts and a exlosion proof bell housing if you run a manual trans. A 383 won't make power to 7000 grand with out some after market heads that flow in the 300 int. range. A 263 273 roller with brodix track 1 heads makes peak horsepower a 6500 and that is in the 560hp range.

[deMideon]

Ok, a few questions for you 350 guys, you can certainly build a 350 to rev to the same RPM as a 377, very easily. The question is, if you have a 383 and a 377 next to each other with the same load, the 377 will rev to the RPM limit faster than the 383. It is a faster reving engine since the pistons and rotating assembly has less distance to travel. Right?

 

Also what about the combustion effeciancy increase with the longer rod to stroke, reducing detonation etc (see I looked it up

 

These are the reasons I went with the 377 in the first place. Am I wrong? (I certainly can be!!)

[Guest Anonymous]

The 350 is a better block than the 400. The 383 will have more torque earlier than the 377 plust the extra 6 cubic inches. What you lose in torque at the start of the race is hard to make up on the big end. If I was going to use a 400 block I would build a 406 or 434. High rpm is hard on parts.

[deMideon]

But with our way lighter cars, is that extra torque even usable? I would think the hookup problems it causes would be an issue. Doesn't less early torque but a faster reving engine help overcome the difference?

[ZROSSA]

I dont think that a compairison of two different cranks in the same engine is really fair. To take advantage of the 377 combo you would want a different head set up to take advantage of the widder bore. Then a different cam.....the list goes on. There was/is a rather large convo going on about hp vs torque at the moment, you should have a read. Now if you dont have any load on these engines the 377 might rev faster, but once you have a load the situation changes. The engine with the most torque under the power curve THAT YOU DRIVE IN is always going to be the fastest.

 

Douglas

[Guest soulfly454]

well im sure you guys will freak out form e telling him this but my mostly stock 283 revs to near 7500 rpms thats all msot stock other then a mild cam and an edelbrok intake and carb no heads or anything now the few times ive done this was becasue i left it in first and floored it not remebrring (damn cell phone) but no breakage or any problems as of yet and this is on a engine that hasent been rebuilt in like 8 years and if you think a 283 is weak you might wanna consider there was and article in hot rod about 25 differnt ways to build a small block and an 8500 rpm 450 hp 283 was one of em or just get one of those votech carb superchargers and that combo will blow away alotta 383's and 377s jsut my thoughts on the lil 283

[Guest Anonymous]

Why would anyone want to build a 283 when you can have a 350 for the same money. Keep on reving that thing to 7500 and you'll be building a new motor too. Just because it can go to 7500 doesn't mean it will stay together. If you have a manual transmission do you also have an SFI bellhousing and SFI flywheel. Hate to have to hear about you getting you foot cut off.

[grumpyvette]

ok I was asked to join in on this

piston speeds over about 4000fpm almost always cause problems

engines that spin over 6200rpm with hydrolic flat tappet lifters or about 7500rpm with flat tappet solid lifters need extensive valvetrain work and rarely last for years

data

the 383 vs 377 debate has been going on for ever, short answer is the 377 can potentially make more hp per displacement but the 383 can potentially make a wider and in most cases more useful tq curve

heres two extremely similar build-ups on DD-2000 changing ONLY the bore stroke and cam to take best advantage of each engines natural piston speed limits

RPM.......383hp/tq........377hp/tq

.

2000........143/376.......142/375

3000........244/427.......241/422

4000........365/479.......361/473

5000........470/493........466/489

6000........517/453........516/451

7000........487/365........505/379

7500........n/a...............485/340

result, no major advantage for either engine

the 383 has a very slight advatage in tq over almost the whole rpm range due to its longer stroke and larger displacement, the 377 has an extra 500 rpm before the same piston speed is reached and better breathing due to its slightly larger bore

now you can play with the cams. compression, port sizes ETC. but the results will remain very similar,

now why not build a 406 for the advantages of both, useing the 377s large bore, the 383s longer stroke, and an increase in displacement over both

heres the same engine as a 406

RPM.......406hp/tq

.

2000........157/412

3000........ 262/459

4000........383/503

5000........483/507

6000........527/462

7000........496/372

[Guest Bob L]

1. Using a 3" stroke is a bad idea. I put a pretty wild 302 Chevy into a Firebird; it really sucked, having spent a lot of money, losing races to lesser built 350s and BBCs. Go big.

 

RPMs = Ruins People's Motors.

 

2. Ask the NMCA guys (nmca-racing.com) about World castings before spending your money. I'd buy the Dart Little M block over the Motown block ANY day.

[Guest Anonymous]

EvilDylan;

 

No matter what block you use or what you do to it, no matter what cam, heads, manifold, pots etc. you tack on, there will always be a peak of 5250 rpm where torque and horsepower cross. Unless your original engine had a "Peaky" cam (whatever that means because cam grinders wouldn't grind peaky cams except on special order and for what reason I can't imagine), the "power band" was there but you wern't properly geared to make use of it. It sounds to me like your cam was ground to "max out" at around 5000 and your gears were forcing the engine to overrun the top end of the "undercurve", and that let the engine flatten out fast because the bottom had fallen out of you torque. In essence, you were running past the top end of the powerband.

 

Burning rubber in second and a squeak in third means nothing more than the fact that you are likely geared too high numerically. If a person say's they are doing this at the low end but then say there is nothing left at the top end this is the first thing that comes to my mind. You have to take the powerband you have and "gear into it" to get rid of that problem. This simply means that if you don't know what the dyno says then you can never expect to dial in the combination correctly except by burdensome trial and error methods.

 

If I am on the wrong track here then pardon me, but if I sound a bell then I suggest you go back and get serious about what you already have. In other words, dig in and analize that puppy all the way! However, if you flat want a screamer then press on in the direction you are headed. But I must say this; The more rpm you want, the longer it takes to wind up through it, and the more rpm you want the more gears it takes to make it useful. The time lost in winding higher (although doing it faster) and the time lost shifting more gears will add up on you and is not a pretty sight when totaled up against the clock where Street/Strip time is concerned. Road racing is more of a matter of driver skill and all around chassis performance of the car which is pitted against the clock in a different manner because of many added variables being introduced.

 

You could probably have saved us all a lot of trouble if you had mentioned exactly what kind of use the car was going to be put to? Road racing=Lots of gears and a screamer -vs- Street/Strip=fewer gears and big bore/stroking.

Now you can't have both and be at the top, but you can split the difference and suffer performance in both fields.....So which is it for you?

[pparaska]

I agree, SPIIRIT, the time it takes to get from idle to peak HP needs to be considered, as well as the torque (or HP) delivered while getting there. The longer stroke will provide more torque on the way up - and that means more acceleration, for the same gearing, etc.

 

Another novel idea here: You have more torque AT WOT than you can use? Well, there's this little pedal on the right that can be adjusted to not be on the floor while accelerating, so that your big stroker motor can mimick the less torquey short stroke engine. Wow!

 

I also agree rpms are expensive to feed for longevity.

 

Oh, and didn't the BowTie block actually come from the design of the 400 block? Just a rumor I heard.

[Guest Anonymous]

Thanks Pete;

 

I am just an old timer pretty well versed in the basics of this stuff, but I have been out of the picture for many years. (However, the basics have not changed).

 

As to your statement about the Bowtie, I have absolutely no idea! I could check it out but I have my hands full with what I am doing.....LOL

[deMideon]

Wow this has been a great thread! I've learned more than I wanted too! I suppose the way I was thinking about the 377 just isn't true. Damn. But it's ok since it will still be a great engine. Not to mention I will be able to stroke it out later when 450hp isn't enough! It's also different than most and I like that too!

[pparaska]

 

It's just that I went the "high revving, quick revving, short stroke" route and found I wanted MORE torque from cruise 1500-6500. I wasn't going to rev my 327 past 6500, since the cam in it would drop off before that anyway (about 6200 rpm peak), and it is about as hairy at idle as I could imagine having on the street.

 

So I took the grump's advice and had a 406 short block built. The cam (Crane 114681, http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=114681)

MAY be a bit too radical at my 2200 rpm cruise, but I kind of doubt it, especially since I'm moving to TB fuel injection. If it is, I'll use the Comp Cams 12-677-4 http://www.compcams.com/information/Search/CamDetails.asp?PartNumber=12-677-4

that's in my 327, which should pull from below 2000 rpm very strong in the 406.

 

Just my personal opinion, but a high rpm powerband can get tiresome on the street.