[strikingthematch]

Of course the 383 wernt meant to turn 6500rpms all day long they are a low end TQ motor But I agree a 350 is still a very good choice though I don't think you will be turn 6500 rpms with it either. Not saying you can't but you won't be doing that very often unless all out drag racing. Street and even in drag strip you might never hit the 6500 mark depending on gearing...

It seems though that it may be easier for you to make the 350 if you can't find someone to do the machine shop work.

Chris

[dawg]

dont forget the 400 flexplate and balancer!

[Hippie]

Originally Posted by NXS

The crank will still have to be balanced or it will basically be like putting a 305 crank in a 350. The 350 pistons are lighter and the cranks bobweights will have to be drilled or it will shake itself apart.

stay smart, stay lean and mean. use a 350. they can turn 6500 on a stock bottom all day long, try that with a 383 bottom-end and see what happens!

I'm sorry but I have to disagree with you on this one, these guys are building a street engine not a drag machine. I'm not trying to be a smartazz or a know-it-all but I built the exact combination he's asking about, I had a "basic" rebuild balance done on it and except for the mild lope of the cam it idled like sewing machine, no vibration at any RPM. It will NOT shake itself apart. The machine shop that did mine had built several for dirt trackers but this was their first street 383, we basically treated it liike a stock 350 rebuild except for the crank swap and a set of ARP rod bolts. I normally shifted it at 5500 but didn't think twice about taking it to 6,000. After I got laid off I needed cash plus I had shelled 3 transmissions in 6 months so I sold the motor to a friend who dropped it in a '71 Monte and added a 100HP Nitrous kit (against my advice) and he took it to 6200 on a regular basis even though I told him it was never intended to spin over 5800. I know for a fact it saw 6500+ more than once. Cast Silvolite pistons, 400 rods, cast crank and all he abused it for 2 or 3 years then sold the car to buy a house. The 3rd owner of the motor did eventually blow it up a couple years after that but the word we got was that he was on the Nitrous button ALL the time. I'm not recommending he try to run it 6500 all day long, we got lucky on mine but there's nothing fragile about them.

Realistically they're probably going to redline it about 5500. It's a torque motor, the whole idea of the 383 originally was to not have to wind it like a 350 but everybody has it in their heads all small blocks have to be wound tighter than a cheap watch to make HP........... treat it like a Pontiac and build it to make torque from an idle to 5500 and it will give excellent reliable street performance for many years. Sure there were faster street cars than mine, there is ALWAYS a faster car no matter what you have but most of them weren't what I personally consider "streetable". Mine would cruise all day long in any kind of weather from 20 below to 100 in the shade and break the tires loose whenever I wanted. I'd build another one just like it in a heartbeat. And yes, I used a 600 cfm mechanical secondary Holley on it. Please don't take this as bragging, arguing or "attitude" it's just cold hard fact. If you were local I'd have you go talk to the guy that helped me drop it in and fire it up 2 days before we left for the Street Machine Nationals in it, Randy Franks in Aledo, IL and the guy I sold it to, Doug House in Milan, IL. Auto Ron's in Davenport, IA did the machine work. Randy and Doug will back me up 100%, I'm sure after 20+ years Ron doesn't remember me but it worked and it worked DAMN good!

[NXS]

Yes, you're right they are building a street machine and not a drag engine. I just like the smooth rpm an internally balanced 350 can give. I don't think 383's are totally useless or i wouldn't have offered him the rods.
I do think that a 383 is more of a truck engine..or a 305 on steroids. It has the small bore to stroke ratio that is for lower rpm and the piston exerts more leverage on the crank therefore producing more Tq. They are great for 4X4's also.

The problem in a street/strip application ( unless slicks are used) is that they produce gobs of Tq and blow the tires off. a 350 trasfers this power (TQ) higher in the rev range and results in more HP( HP is a resultant of RPM with 5252 being the RPM constant at which every engine begins to produce more HP than Tq.)

That being said I don't doubt your story about the 383 meant for 5800 MAX and it being turned 6200. I would however like to know the weight of factory 5.565" rods VS factory 5.7" rods and the weight of the factory 350 piston VS the weight of the factory 400 piston.

[Hippie]

Found these in the "archives", my 383 and Chevelle.........

Originally Posted by NXS

I do think that a 383 is more of a truck engine..or a 305 on steroids. It has the small bore to stroke ratio that is for lower rpm and the piston exerts more leverage on the crank therefore producing more Tq. They are great for 4X4's also.

The problem in a street/strip application ( unless slicks are used) is that they produce gobs of Tq and blow the tires off. a 350 trasfers this power (TQ) higher in the rev range and results in more HP( HP is a resultant of RPM with 5252 being the RPM constant at which every engine begins to produce more HP than Tq.)

That being said I don't doubt your story about the 383 meant for 5800 MAX and it being turned 6200. I would however like to know the weight of factory 5.565" rods VS factory 5.7" rods and the weight of the factory 350 piston VS the weight of the factory 400 piston.

Well here again we differ in our opinion I think blowing the tires off is the great thing about the 383. but then I'm one of those "immature" hotrodders LOL. Sorry if I climbed on the soap box but I am a HUGE fan of torque motors both figuratively and literally , I cut my performance teeth on Pontiacs and was exposed to all kinds of GTO' 442s and Buick GS's as a kid. We kind of looked on SBC's like people look at ricers now, damn mosquitoes buzzin' around! J/K

I'd be willing to bet the weight of a .030" over 350 cast piston on a 400 rod isn't a whole lot lighter than a standard bore 400 piston on a 400 rod but yeah, I'm curious too.

[NXS]

Nice engine, really nice car!


While we wait for somebody that knows the weights of those 4 componets let's consider something. If we say that a stock style 383 has a max safe rpm of 5500 rpm and that a 350 has a max safe rpm of 6250( I personally think 6500) and we figure the CFM needed @ 100% VE we get 609 CFM for the 383 and 632 for the 350 we can see that a 350 can make more power with greater reliability.

[strikingthematch]

it's a pretty well known fact that 383s like to breath. The use bigger carbs and sometimes diffrent intakes it's just something that goes with the long stroke combo.

I agree though that it is possible to produce to much TQ for the strip... however when driving around it's not like you can't not floor it your not going to break the tires loose all the time.
ANother thing to remeber is that the 383 does not rev. like a 350 and so all the bottom end TQ is going ot come in at once but the engine will do it without having to hit 6500 in my mind that makes the 383 pefect for any heavy street/strip car.
If you keep those tires planted and or have the correct gearing you can get off the line just as quick as someone with the 350. The problem is that there is to many "x's" to figure this out any one thing could make a better engine.

I still stand that for a street car the 383 will produce more "fun" factor in that you can burn the tires at will (not that you can't in a 350) but RPM wise the 383 can make the same kind of power but do it at a lower RPM.
We really arent talking HP it is more just TQ a 383 is not going to gain much HP but it will "out muscle" the 350 in a tug of war between the two engines.

Once again either engine is good and both can be made to beat the other flat out it is more or less a combo of parts but if your looking for low end and a short power curve go 383. For a more peaky curve go 350 and with the right gearing you can make it feel just like that 383. It's all a question of what you want.

Chris

[Hippie]

Originally Posted by strikingthematch

it's a pretty well known fact that 383s like to breath. The use bigger carbs and sometimes diffrent intakes it's just something that goes with the long stroke combo.

I agree though that it is possible to produce to much TQ for the strip... however when driving around it's not like you can't not floor it your not going to break the tires loose all the time.
ANother thing to remeber is that the 383 does not rev. like a 350 and so all the bottom end TQ is going ot come in at once but the engine will do it without having to hit 6500 in my mind that makes the 383 pefect for any heavy street/strip car.
If you keep those tires planted and or have the correct gearing you can get off the line just as quick as someone with the 350. The problem is that there is to many "x's" to figure this out any one thing could make a better engine.

I still stand that for a street car the 383 will produce more "fun" factor in that you can burn the tires at will (not that you can't in a 350) but RPM wise the 383 can make the same kind of power but do it at a lower RPM.
We really arent talking HP it is more just TQ a 383 is not going to gain much HP but it will "out muscle" the 350 in a tug of war between the two engines.

Once again either engine is good and both can be made to beat the other flat out it is more or less a combo of parts but if your looking for low end and a short power curve go 383. For a more peaky curve go 350 and with the right gearing you can make it feel just like that 383. It's all a question of what you want.

Chris

Thanks. You just saved me a WHOLE bunch of typing! ...........yeah what he said! Although with that much torque "on tap" it IS hard to "not floor it".....

[Houman SS '70]

Originally Posted by Hippie

Thanks. You just saved me a WHOLE bunch of typing! ...........yeah what he said! Although with that much torque "on tap" it IS hard to "not floor it".....

Glenn,

Man I'm really getting excited with this 383 TQ thing.
Do you think that for 1/4 mile, TQ is more necessary or HP?
If you even suggest the same for my own car, I can still switch to a 400 crank??

What do you say? Is this 383 a good choice also for my own car?
I have a Pontiac 455 H.O., which I can change it with some 4 bolt main 350 block and a 400 or 350 crank. My friend keeps telling me that I should keep the 455, so that one day I can buy a Pontiac and throw it in there??
But I really don't have too much space to keep this piece of scrap. I really don't like Pontiac engines, I don't know why.

Any way, if you think that a 400 crank and it's rods, with my own setup will also work, it's not too late?

Or, maybe I should make a 383 separately and keep it for some other time?

Tell me.

Take care,
Houman

[strikingthematch]

To tell you the truth it a matter of what you want. The bigger CI engine you have could make much more pwoer then the 383 but that fact that you don't like working on them makes the point moot.
If you sell the engine you could get money to work on your own which is good and then be able to build an engine how you want and like doing it.

As for the TQ yes they do have lots not that its going to be a rocket ship but sitting next to your normal 350 you will feel it.
When at the strip it is important to have a mix between the two for a street/strip car. You don't want to burn your tires off and then hardly get up to speed going down the track. Most of this is taken care of with correct gearing in the rear being able to work the entire powerband. In a heavy car the fist few sec. are very important.

Think of it this way to get your car moving you use TQ now HP will take you the distance. Some engines set up work will for a narrow rpm band and so leading up to and after it they don't make as much power with the 383 the curve is much less and it allows you to make good (might be less then the other) but for the entire time. If the diff. in rev ability is 5500 to 6500 then even though your 383 may make less HP over all it will make good HP the entire time and when geared correctly that is a killer set up.

Chris

[Hippie]

Originally Posted by strikingthematch

To tell you the truth it a matter of what you want. The bigger CI engine you have could make much more pwoer then the 383 but that fact that you don't like working on them makes the point moot.
If you sell the engine you could get money to work on your own which is good and then be able to build an engine how you want and like doing it.

As for the TQ yes they do have lots not that its going to be a rocket ship but sitting next to your normal 350 you will feel it.
When at the strip it is important to have a mix between the two for a street/strip car. You don't want to burn your tires off and then hardly get up to speed going down the track. Most of this is taken care of with correct gearing in the rear being able to work the entire powerband. In a heavy car the fist few sec. are very important.

Think of it this way to get your car moving you use TQ now HP will take you the distance. Some engines set up work will for a narrow rpm band and so leading up to and after it they don't make as much power with the 383 the curve is much less and it allows you to make good (might be less then the other) but for the entire time. If the diff. in rev ability is 5500 to 6500 then even though your 383 may make less HP over all it will make good HP the entire time and when geared correctly that is a killer set up.

Chris

Yep that pretty much covers it........... Chris, my fingers are in your debt again BUT all that said a 383 won't make anywhere near the torque of a properly tuned 455 HO. I can understand wanting a Chevy engine in your Camaro but I would LOVE to get my hands on that HO. I do like Pontiacs and of the D-port motors that or the 1969 428/390HP woud be my first picks. Those things were torque monsters!!! Dyno tuned with a good TH400 and 3.31 gears in a nice light '65 GTO, '72 Ventura or 1st Gen Bird and you're talking an honest high 12 second street car with the manners of Aunt Mabel's Catalina........ for all you doubters back in the day I saw a 455 HO powered '70 Formula Firebird do just that, stock from air cleaner to oil pan with some serious tweaking on the carb, ignition and suspension........ if I'm lyin', I'm dyin'.

[strikingthematch]

Yeah like I said you really won't beat the the larger CI engine when built. Problem is I know he has trouble getting parts for the 350 so getting those parts might be even harder. For most people who do have that engine building it would be a joy but when ya can't get the parts... Not to mention the fact that he said he really dosent like working on them so I guess I should just take the block lol

Chris

[PatM]

One other thing no one has mentioned. It seems to me that the block needs to be clearanced a bit to build a 383. Wrong??

[strikingthematch]

That can be true mainly around the oil pan rail some blocks need it other don't it's one of those block by block things. The job can be done by yourself though a simple die grinder and a few times mock up will put you in good shape.

Chris

[Hippie]

Originally Posted by PatM

One other thing no one has mentioned. It seems to me that the block needs to be clearanced a bit to build a 383. Wrong??

Not needed when using 400 rods but some blocks need a "touch" in a spot ot two with the die grinder or needle sander when using 5.7 or longer rods.

On the 455 HO.......

Originally Posted by strikingthematch

Problem is I know he has trouble getting parts for the 350 so getting those parts might be even harder.

Good point.........