383 stroker cam ?

[markmitchinnh]

I am building a 383 stroker with a 1990 4 bolt 350 block and vortec heads I will be using a 4 barrel intake and carb.
I want a cam that is easy on the drivability and yet has a bit of a cammed sound to it (rumpity rump)
any ideas feel free to speak, I would also like to know what size carb you may recommend I will be using an Edelbrock.
Don't care for Holleys they are made in china as well as all Accel parts.

[1Gary]

Which cam is somewhat dictated by static compression ratio.Need more details about your build.

Not a big fan of vortec heads because they do raise compression ratios,but really don't flow that well.That becomes a issue when you have a bigger engine and your not filling it as it should.RHS cast iron heads are a great buy that addresses that issue and don't cost the much when you consider what you are getting and how much you are paying.When it comes to heads after the extensive research I have done,that will be the heads of choice for my 383.

But to get back to what I said,Please post your build with maybe part numbers,if you are building a roller engine or conversion roller engine,maybe what you have bought already.

[markmitchinnh]

Well I already put money into the heads, porting and they are shaved a bit too. I wish to go with 10:to 1 compression.
non roller cam (because the options and cost) the block will most likely be bored .30 over stock. most likely go with this kit.


http://www.rpmmachine.com/chevy-sb-menu.shtml



I have not started on this engine yet it is in the planning stages but the heads are done because I was going to build this a year ago but got hurt so I am mow getting to it.

[1Gary]

Before you buy,I suggest you google brand names of kits to see user reviews.Here are some links to get you started:

http://www.speedtalk.com/forum/viewtopi ... 9b21951a5e

http://www.hotrodders.com/forum/eagle-s ... 32551.html

The Eagle stuff is forged off shore and machined off shore.User reviews is taper journals size issues,size issues,cracked journals when mag'ed right out of the box.Not much to be saved in the long run here.I suggest avoid this
brand name.Many,many quality control issues.

The Scat brand name is forged off shore and machined here.The cast crank issues are alittle better,but not by much.Same holds true for the forged steel cranks.I found that the Scat rods are pretty decent and the ones I will be using is part number SCR5A7.A H-beam rod that is profiled for stroker clearance.When we get them,we will still mag them and size them to make sure they are correct.

The Howard brand name is right as rain.Round and finished is outstanding balanced right on the money.These cranks are for the long run worth it.

I am right now running out of time needing to get ready for work.I want to tell you tons more and will later.

Leave you with this thought.Suggest you don't loose sight of the combo your building and how those parts are mixed together for a good end result or not.In that regard I posted a thread for best builds.Do a search on my user and might want to look at that too.

[1Gary]

So Mark to answer your question of which cam.......need to know the static compression ratio.Long,long link,but one the is critical to cam choice:

viewtopic.php?f=4&t=6373

You have to know the head's cc's to make a informed decision.This is what values you need to know to figure out the static compression ratio:

viewtopic.php?f=4&t=6252

Here is a link of copied 100 SBC combo's and dyno'ed.This is I think more entertainment value than a guide of which parts or cam given a engine's compression ratio.Might be a good read for ya in your spare time.Got to look beyond the bible part of it.

http://www.ryanscarpage.50megs.com/combos1.html

I am thinking about the series of flat tappet cams from Comp Cams for your application.Once you know more,I could suggest which of the 270 or 280 series cam to look at.The torque converter you use will also come into play as well as the tire size/rear end gear ratio.Here is a example of what Jeg's lists for different Comp cams at the bottom of the page of the link.

http://www.jegs.com/i/Comp+Cams/249/12-212-2/10002/-1

All and all Mark-I am trying to insure you get the biggest bang for your buck.

[6spd_monte]

In case we don't have enough engine building info, here's some more reading on Dynamic Compression Ratio.

http://www.empirenet.com/pkelley2/DynamicCR.html

[1Gary]

Yep-I admit I took the risk of conveying all this info to you guys.Found the days of picking the baddest,biggest cam of days of old are gone.The understanding of how things work and the tech that goes into that has created what builds deal with now.Ever wonder after seeing a vehicle be a real bear and then open the hood to look down at what seems like not much??.Idle like silk but when you stomp on the gas wants to tear you face off with torque and as it gains speed quickly gives you a side view of what is there in a blur.

Honestly just trying to help.

Mark,you said to give you feedback on your build.Here is a short-cut version.A 383 with a compression ratio of 10 to 1 or near that needs to have a intake runner of 200cc and those Vortec's are good in use of some limited applications for 350's but will never have enough volume for your 383.So you can pick any cam you want,but it will be limited by your head selection.

Also-you have to bore your block .030 over in order to get to the size of 383.

[lockdoc]

Here is GM's version of the 383.http://paceperformance.com/i-5136493-12 ... ngine.html It uses the Vortec heads as well. 435 lbs of torque. WOW! It all depends on what you want it to do but GM's is a very dependable engine. Unlike Gary I think the Vortec heads are the biggest bang for the buck out there. Sure there is better but the price is awesome for what you get. You can get the stock roller lifter setup for your block fairly cheap as your 90 block should be machined for it already.

[1Gary]

Bill-I agree with you that is one stout engine.Not a bad price either.Thing is they used a 3.80 stroke(not the usually 3.75)which added "some dwell" at TDC and a compression ratio of 9.1.The engine peaks at around 4,000 to 4,500 in torque and HP.That is the indication of the limits of the heads and not being able to flow air,cam choice,small valves,not enough air.

Same holds true with outfitting a engine with a cam that works with a given compression ratio,you have to follow that threw with a set of matched heads.I think he was talking 9.5 or better and therefor needing more cc's in the intake runner.The Pro Action RHS stage ones are 202 intakes/1.60 exhaust(not 1.94/1.50's in vortex's) and the first level assemblies have #3250 7" moly retainers,#4232 7" heat treated valve locks,springs good enough for lift to .560,one pc chrome stems racing valves,guide plates,3/8 or 7/16 ARP studs,umbrella seals and all that for only $869.00.And a 200 CC intake runner.

That is a Competition Products price which is free shipping.Considering all that is a big bang for your buck that is a matched set up for a compression ratio of 9.5 or better.

The rule of thumb is a formula of .5 X the size of the engine.So 195 CC for a 383 is about right.Well a 200 cc head is in the same ballpark.Stock I am guessing,but I think they are about 165 CC intake runner.

[markmitchinnh]

Ok well I found out today that the machine shop I am going to use recommends scat crank kits and even sells them so I will go and have a sit down with them soon and let you know what I found out. Thank you all for the input. Mark

[1Gary]

Mark(and all those reading this)-I am not trying to take over this thread and I am very,very sensitive to the amount of info I have posted to it.

Mark I did read two Scat users who had the misfortune of a crank that broke
right behind main journal number two when a crack wasn't found in advance and they where just driving them.Nothing crazy like spraying it or anything.Taper issues on journals that required the cranks to be turned down 10/10 right out the box.Oh,I wanted to tell you in both cases I read about with broken cranks,Scat refused to stand behind them.That turned me right off right then and there.

Mark-for me anyways,I can't afford any major problems with my build.I have spent this time to select the parts I have to pay it forward so to speak to prevent them.Because of that I do hope to get yrs and yrs of dependable reliable performance.Read threw the lines of what people have told me and kept that I know to apply for my build.So listen to what they tell you and ask questions.These builds are not cheap.

It is solely because of yrs ago Lockdoc told me at a NECO that I should just build a 355 and what yr truck engines for what I want to use it for that keeps me grounded every time I look at parts and the devil Hot Rodder comes out of me to just go for it with high compression ratio's etc.For that msg to continue to play in my head I owe Lockdoc tons.Not building a 355,but Bill did influence many of the choices I have made even through he doesn't know it until now.

[markmitchinnh]

well thank you, I really do not need a stroker V8 I just never built one so I figured what the hey. I originally was going to build a 305 with a stroker kit then pure luck gave me the 350 free with 100,000 + miles on it but still running fine.

[Mr_Roboto]

Even the best MFGs have stuff break. Scat rods are supposedly better quality than Eagles out of the box but I wouldn't be afraid of either on the crank. Regardless of what you do GET IT CHECKED. It doesn't matter if you use OEM parts and remachine them or get a $10,000 rotating assembly. Do you think that any of the huge engine builders just throw the stuff together because it came from a huge name and they payed a fortune for it?

If you can find one that's machined a fresh 400 crank cut to 350 journals is not a bad way to go. Hell even 5.65 rods aren't a bad way to go if you're on a budget. You'll lose some engine life and a bit of torque but it's fairly minor compared to the gains of the extra displacement and I believe less grinding on the block too.

Do a roller cam, it's some extra $ but well worth it. Elgin sells a roller that's 230/230 for under $200 and should give you quite a bit of lope. This is the one spot I wouldn't cheap out these days, heard of too many flat tappets biting the dust. My current 305 is a flat tappet but it's also a very low budget engine that I intend not to run very long (power adder grenade) so that is why I used a tappet cam. My next engine has a stock TPI roller in it, while dirt tame is way better than the cam that was in the stock TBI engines.

Vortec heads can and are fine for what they are. You can get 400hp off a set of lightly modified Vortecs with a few tweaks. If you have a shop do the work, keep that cost in mind as well as any intake cost differences. At some point a set of World S/Rs or Dart Iron Eagles start looking good. Or hell even a set of the Edelbrock Aluminum heads with 86 and earlier patterns.

All the advice above is dependent on your secondary market as well. I'm HUGE into the secondary market, if I can get an intake for $50 on ebay or Craigslist instead of a new $250-300 that money can get applied to the heads instead.

[1Gary]

The use of 5.56 rods increase the likelihood,depending a piston selection,of interference issues.

As I stated,I am planning to use Scat rods part number SCR5A7.I will have to spend extra money to have them balanced and they will be checked completely before installed.Paying extra money for the middle grade rods.

www.Engine-builder.com

Has a link for rods which explains tons:

http://www.enginebuildermag.com/Article ... rings.aspx

Aside from trying to find a good set of Vortec heads that are not cracked,where they fall down is they surely do increase the compression ratio's,they don't have the flow figures to support any real gains.Just as Mr_Roboto stated you don't want big intake runners,but something middle of the road.Not 200 cc but more like 195's or 180's.My choice given a compression ratio of 9.0 is RHS part number 12301-02.It is a 180cc runner with 202 intake valve.That keeps the viscosity up and builds torque.It is also good vacuum builder for the fuel injection.Aside from compression,most of the power building is on the top haft of these SBC's.As this link states,not much is gained by pocked porting for a street driven engine.

http://www.enginebuildermag.com/Article ... ocity.aspx

As for a cam-I totally agree with a roller cam even if you have to spend more money for a aftermarket conversion kit to get er done.Thing about the Vortec heads here again being mis-matched is trying it has a higher compression ratio and a inability to supply flow for higher RPM ranges.Then you try to use the stock roller spider retainers which have a very limited higher RPM range without valve float.Comp Cams has a fix for that,but is still limited.One thing to keep in mind that you can take to the bank,is 383's love a longer duration on the exhaust side.It is something you should look for when researching for a cam.Also,keep in mind that many of the stock timing gear sets from newer engines are machined 2 degrees retarded for emissions.You need to degree your cam choice to check to that.Lastly if you have to retard or advance you cam more than 4 degrees to get the performance you want,you have chosen that wrong parts combo.

So to sum it up,the Vortec heads do create a higher compression ratio which is asking for a bigger cam but doesn't flow well for support the higher RPM ranges and the stock spider retainers doesn't allow for a higher RPM range either.Thus a mis-match is created.

I do use engine-builder as a ref because it is geared towards business's that build engines which are starving towards trouble free customer satisfaction and has postings from people who have done that,been there.