killerIROC

I talked to a shop about stroking my L98 to a 383, and he said that with a mild cam and pocket porting the stock heads, 100hp and 75lb-ft of torque was expected. He also said if you have the stock heads and cam and you stroke it, the car will run like crap, is this true? And also, what kind of power ratings can be expected with a 355 similarly built? Are there any advantages a 355 as over a 383, other than gas mileage? I know the 383 will make more power, but Im just curious. Thanks

Tom84L69

I can't imagine building a 383 and leaving the stock cam and heads on it. The motor has to come all the way out anyway, why not make some improvements?

Advantage of a 355 over a 383: Cost. I bet fuel mileage wouldn't be much different.

ChrisFormula355

advantage of a 355 over a 383 is that it will spin higher

smithtc

iTrader: (5)

Can you explain why you think a 355 will spin higher?

I think that is an overestimate for a mild cam and pocket ported L98 heads on a 383...but possible. Can you get that in writing?

I believe so. The engine will be suffocating for air, and the power produced will be at lower rpms.

Lot of variables (induction, cam used, exhaust). 9% smaller engine than the 383...plus however much less-efficient the 355 is compared to the 383, and the 383 making power at higher rpms than the 355. Just say 20% less efficient (liberal estimate)...100hp*.91*.80=72 hp
That is if you make the extra 100 hp.

One man's opinion...

Here's a recent post where someone switched out the short block to a 383:
https://www.thirdgen.org/techbb2/sho...&highlight=383

D's89IROCZ

355 will rev higher becasue of the shorter stroke

smithtc

iTrader: (5)

Within the context of the original set of questions, I don't think you can guarantee that the/a 355 will spin higher than a 383.

How much greater potential does a 355 have to spin higher than the 383??? When it gets right down to it, I don't think it is that much. The higher spin capability will not outweigh the bigger cubes in 95% of situations, anyway...I would think...so I don't see that as a benefit. I do remember reading about a Corvette in street trim doing 8s in qtr mile with a high reving 327 bored out...but with a awesome amount of nitrous.

erummel

iTrader: (2)

Displacment does not limit how fast you can spin and engine. Any engine can be built to spin to whatever RPM you want... as long as you are willing to pay for it.

Providing that the only difference between the two motors is diplacement, the difference regarding the RPM range between a 350 and 383 is that the 383 will make more power (it is larger) and do so sooner (i.e. lower in the rpm range) than the 350.

The 350 will have to rev higher to make the same power as the 383.


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rustybluebird

Stroke has sweet FA to do with an engines ability to "rev".
Shortblock quality, heads+ induction, cam, exhaust, etc have evrything to do with a "high revving engine".
Who gives a rats Ahole how high a motor can rev, how much power does it make?

D's89IROCZ

noo need to get nasty ......just posting some things I have read about....thats all .

ChrisFormula355

Like somebody else said........at least I think they said.........a 355 will spin higher and make better DRAG STRIP top end power because it has a close stroke/bore ratio, where as in your typical budget 383, its a long stroke, but still a 4 inch bore. With enough money, its easy to overcome this by doing other things to the engine (different length rods, pistons, ect...). DOLLAR FOR DOLLAR, a 383 will not surpass a 355 in ultimate horsepower production by the simple fact that the addition money spent in machine work, ext. balancing, custom rotating assembly, ect could be better spent on other things, like towards a blower or a plate system. remember the old motto.

K.I.S.S!!

Keep It Simple Stupid!

a monkey could rebuild a 350, and its dirt cheap to build.

and if a 350 is so bad of an engine, why does my firebird go 11's? hmmmm.

Enkil

If all else is equal except the stroke between the 355 and the 383, the 355 can rev up more quickly, because of the shorter stroke. Whether or not that's an advantage depends on what you're building. Personally, I think, and I quote someone from CorvetteForum.com, "Whatever the question is, the answer's big block."

kevinc

If you read them here on thirdgen.org where compression ratio increases as the engine gets hotter and you can use tapered-seat plugs on flat-seat heads, I'd be hesitant to quote it as gospel...

The longer-stroke engines don't like to rev high, this much is true...however they also don't need to rev as high.

Anyone else watch the American LeMans Series races this season? When they switch to the cockpit cam on the C5R Corvette with it's 427ci LS1, the thing sounds like he's barely hitting 5K rpm. Nice, conservative, low-end grunt gets those cars around the track for 24 consecutive hours...and they just won the manufacturer's title for the 3rd year in a row.

D's89IROCZ

thats all I was trying to get across .......... not what makes power where and that sort ....

that's how come the 327 ( 4"x 3.25") and 302 (4'x 3")were known as screamers no?



K .... so back to the first Q ......... I see cost as the big bonus over the 383 ..... and well from the guys at the track etc ....... you can buy parts for both setups ....... that will put you wayyyyy beyond where you want to go . It's just picking your starting point I guess .I went 355 becasue of the cost ..... is it better ? I am almost sure that it is/isn't ........ it's just up to the owner ....or if this car it's goning in has a defined purpose. THEN it may matter more to you .


Good luck and keep it between the ditches

snakeskinner

have I been gone that long.... How did so many "know it alls" get on here. I have a 383 in my car and the heads suck so I can tell you first hand what will happen. You have gobbs and gobbs of low end torque because of the long stroke and larger displacement but at higher rpm's you lose power. I went from a 350 to a 383 and used the same heads (with bad porting). My 1/4 times didn't change much but I can now pull cars a full second faster than me till about 200 feet out when I run out of air. Now for the rpm battle these so called experts are spouting off over. You could rev a 383 as high as the 355.....for a while anyway but why????? The whole principal of a 383 is not top end horsepower, it's for low and midrange torque. Revving past about 6500 would be stupid because you're past your torque range. a 350's shorter stroke allows for more top end horsepower for several reasons. #1 reason is that there is less weight thrown out a shorter distance. The more the weight placed farther from the centerline will ALWAYS need a slower rpm. Sure, you can use lightweight cranks, rods and pistons and rev a 383 to keep up with a 350 but like I said... why?? On a level playing field, a 350 and a 383 revved to the same rpm's, the 383 won't last as long before coming apart. I've seen 350's revved to 8k rpm's with stock rods. You do that with a 383 and you'll have lots of parts in the pan. If you're going to use stock top end, stay with a 350 just like the shop told you. You will definitely spend more money for the 383 but it is a lot more fun....

RB83L69

I wish there was a way to administer some kind of achievement test to filter some of that out.... there do seem to be alot of people here lately trying to give technical answers but getting their facts completely wrong, and then starting flame wars when someone with more knowledge or experience comes up with the truth....

I think if I see another post about how a 377 or 302 can "rev to the moon" but a 350 (with the same stroke as a 377) can't, or how a Buick 6-cyl motor is somehow an inherently "better" motor because they made a turbo version of it at the factory, or how GM actually made 350/5-spd cars and didn't tell anybody, etc. etc. etc., I'm going to hurl all over my screen.

Ricktpi

I don't know about hurling, but it is entertaining, kind of like watching a train wreck in slow motion. They don't seem to want to learn or listen, so let them wallow in their ignorance.

smithtc

iTrader: (5)

I atempted to answer the question, giving my opinion, or what I thought...knowing others would eventually jump in on this topic.

Did anything I wrote not have merit? I'd like to know for sure...

Hodge

didn't anyone else notice that he is putting this on a L98. Hence TPI.

unless you have a highly modified (from stock) induction system the 383 will be choking. so will the 355 for that matter but not as badly.

also consider that this is a computer controlled set-up and the tables will need tobe modified if he changes too many things.

Ricktpi

This guy seems to have a grip on this.

I went the 383 route & will never go back.

BTW, I am the guy that swapped the 350 shortblock for the 383 that smithtc is referring to.

D's89IROCZ

hmmm short block vs ....long block ........ withou heads .....or with heads


isn't that the difference between the two



if so ........... who cares if you swapped a shortblock out. It has nothing to do with this discussion .


now try to input some fact to this ....... as it would "appear " that there is none ( i disagree ) .

Ricktpi

It has everything to do with it. Look at this thread: https://www.thirdgen.org/techbb2/sho...&highlight=383
My car gained .8 sec & 5 mph with a change from a 350 shortblock to a 383. Same heads, cam & exhaust. And correct me if I'm wrong the originator of this post was/is trying to decide on a 350 or 383.

D's89IROCZ

I stand corrected ! but the C/R is higher ......but I gotta tell ya man ....... that is a very nice setup . But the originator was asking about a 355 vs. 383 .


Nice car man !

Ricktpi

Thanks. I think the biggest improvement was in low end torque. The car launched harder & the shorttime went from 2.xx to 1.7. 350, 355, 358 all the same animal as far as performance goes.

AJ_92RS

If you have the money to spend (which normally isn't a whole lot more) build the 383.

By far, displacement is the cheapest power adder available (short of nitrous ).

People get all into this "this engine will rev higher" and all that crap. My Suzuki Bandit 1200 (1157cc's) revs to 13,000 RPM. Does that mean I want it in my Camaro???

You can build ANY engine to rev higher, but that's not always the smart thing to do. The smart thing to do is build the engine for what it's designed to do.

As someone pointed out, a 383 has a longer stroke than a 350, which applies more torque. Why build it to rev high? That's makes as much sense as building a 302 for a tow truck.

camarojoe

RMP limits and how high you should take your engine, should be more defined as what you want the car to be. If you want it to rev past 6k then it's all in teh rod/stroke ratio. Take your rod length div. by your stroke. A 3.75 crank with a 5.7 rod will have a lower ratio than a 5.7rod/3.48 stroke. That's why people always say a 355 will rev better. It's all about piston dwell and the better (higher) the ratio, the longer the piston will stay at top dead center (more hp) which =less side loading on the cylinder and better rpm capabilities. Longer rods is the way to correct for or make a long stroke engine rev up better. Get the longest rods you can, which is usually maxxed at 6" on a sbc.

Like AJ said, why rev a 383 or 400sbc, when they do so good in the midrange? Unless your nuts like me and some others, use the tq adv. of a 3.75 stroke. There's no doubt that anyone rebuilding their 350 should upgrade to the longer stoke if they want more power.

killerIROC

Well I think the money will be the only thing stopping me from going one way or another. I'm leaving for the Army in July, and even though military personel don't get paid alot, it is plenty anough to build a streetable muslce car. And I'm not using the TPI setup, by the way, I really wanted to use to HSR so my top end wasn't so crapping. But I'm still not sure which way I want to go. I haven't read many posts on a 383 HSR SBC, so I'm still in the dark on how that would turn out, or a 355 HSR for that matter! My major goal is to being running around 12.0 in the 1/4, and still be able to drive on the street. I want to do this NA of course, and maybe later had a blower or no2. I'm not sure how it will end up but all this input is great, thanks!!