grammerman

Haven't been able to dig up any good threads on this subject. My LT1 is going back with 383 bottom end, around 11:1 with mahle 16cc dish top pistons and pretty sure at this point a GM LT4 Hot Cam.
The stock LT1 heads have had the pocket volume increased a good bit ( deeper on both sides of the guide when streamlining guides) with a port bias established a la David Vizard's book and should flow a good bit better than stock. I'm looking for info. on whether it's worth about $250 extra to buy a set of 2.0/1.55 stainless valves from Lingenfelter ( price includes extra labor to open up seats when 3 angle is done) as far as a justifiable power increase. I don't think 5 horsepower would be a very good bargain at this price but maybe the larger valves would be worth more with this combo? It's not really a huge cam with tons of duration and the ports haven't been hogged out in the heads so I'm really not sure.
Thanks, Michael

1racerdude

The only way ya gonna make it run(make HP) is with 2.0 intakes and 300+CFM flow and a REAL cam.

grammerman

That really helps. Since it will be driven 50 miles back and forth every day to work in traffic I really need an overcammed track refugee that will only "run" with a 4.11 gear. 350 plus crank horsepower is pretty respectable and the pussified lowend produced by big cams makes your engine feel pathetic when you're not running hard. 99% of my running will be on the interstate and in traffic at under 4K so a big cam and hogged out 300 cfm ports would be stupid.
If anyone who knows a little about REAL street engines wants to contribute something USEFUL on what to expect from a valve upgrade with a mild street cam and ports then be my guest.
Thanks, UnREAL cam dude

sleeperMULLET

i think what 1racerdude is trying to tell you is, you will be starving the engine for air if you do not upgrade the valves. So its not really about the HP gain, but making the engine run how its supposed too. So to answer your question, yes, get bigger valves, and make the heads flow better, but lose the attitude.

1racerdude

Well ya can run a 240/250@50 hyd roller on the street and is being done ALL the time.
If ya don't want HP then WHY build a 383 when a 356 would probably do ya. A little asinine don't ya think.
What's the deal with 2.0 valves if ya want NO HP just leave the stock heads on there and it will run out of wind about 5500,kinda like a governor, Yep that makes sense.
If ya want a car for mileage and not unruly a Honda Civic comes to mine.


Ya are quite welcome.

grammerman

Well, maybe I was a tiny bit over the top
Point was that while most people on here might not mind
the compromises involved with driving a race engine every day I in fact do. Compromises like surging at cruise engine speeds, rough idle, poor fuel economy, much shorter engine life ( especially valvetrain), finicky tuning, poor lowend and midrange throttle response, etc, etc, etc.
There's miles of room between a stock head and cam 355 and a 383
with a monster cam like rocketboy says I should build if I don't want a stock rebuild. Seems like a lot of the posts I see on here admonish people for daring to post about a sensible daily driver build.
And by the way dude with 50 posts under your belt, if I want to mildly harrass someone who takes my thread off on a tangent with goofy advice then I will. You don't have to like it.
If you're going to race a lot then go ahead and build something close to a race motor and don't be surprised when it lasts like one. I want a fast street ride with excellent long term durability ( like 100K plus miles without problems) and it makes much better sense to build something between a race engine and a stocker. I don't even feel a bit ashamed.

1racerdude

Ya don't have to take ANYBODYS advice.
But if ya are building a TOW TRUCK yours would be the engine for it.
We don't harass anybody on this board so ya can take it for what it is worth.

Ya don't have to get advice from anyone on this board either but if ya do don't come on with the 'tude ya got ya may get some good advice.
I have built as many engines as anybody in the 40 yrs I have been doing it and ya don't have to take my advice at all. That 383 will EAT that"POS" Hot Cam alive and if ya don't give it some air it ain't gonna be worth anything but a laughing stock for everybody or a pickup truck.

Rocketboy and that's Mr. to you.

sleeperMULLET

I was just trying to help man, A 383 needs more air then stock 350 heads can flow. The member whose advice your calling goofy has over 5,000 posts, I may only have 50 posts but it doesn't show the thousands of hours of schooling, factory training, tests, recreational reading, and working on cars for a living. I'm new to the Hi-performance scene, especially LT1s, but it still works the same way any other engine does. I'm sure you'll find some of the best LT1 guys on here and I would take thier advice.

grammerman

If you are doing a rebuild with a damaged crank like I am why not throw a 383 crank in for the same money? A 383 is less than a 10% displacement increase so unless you are trying to up the horsepower by 50% it just doesn't fly that you need 300 cfm ports. I've done big bore kits on motorcycles for years and without any cylinder porting they still come alive and are far more fun to ride.
Check out post number 14 from the link below. 118 mph with a 211,219 duration cam,ported heads and midlength headers. Must be the fastest tow truck engine around. I guess it's normal to get jaded in the race for ever increasing amounts of horsepower and forget the fun of driving a torquey and fast street motor. Sounds romantic, doesn't it?

http://web.camaross.com/forums/showthread.php?t=453533

sbs

Dude you're an idiot coming on here and at post #10 you're already insulting one of the most knowledgable engine builders here.

You're also an idiot to spend the money for a 383 with a goal of 350 FWHP.

grammerman

Surprise, surprise. Another idiotic post saying go big or go home and zealously defending others who do the same. How original. How quaint.

med_reject

280+ cfm heads make peak power at <6000rpm on a 383, your heads will give up at 4000rpm, not even 5k, but whats done is done.

To answer your original question, the bigger valves alone wont do much for your motor. As you must know, everything works as a system and we need to know what you want before we can give you advice. 383 implied you wanted power, so the hotcam and stock heads confused people here.

If you get a good port job (eg. LE), the 2.0 valves will get you maybe 15hp over stock valves. Its really hard to say how much extra hp they will give in your application.

94CamaroZ28

In absolute fact, the hotcam is a really poor choice these days. There are a wide variety of better cams out there, particularly for larger displacement engines. Stock heads are not bad, but can stand some significant porting for use with larger displacement engines. Bigger valves, by themselves, will not hurt upper rpm flow, but you may well find that the relatively stock heads you mention will not benefit much if at all. As mentioned by others, consider the overall package.

Also, the driveability issue and longevity issues don't really apply to mild/medium cams, if properly set up and dyno tuned. Certainly they apply to really big cams; a daily driver wants low/mid and power under the curve, even at the expense of top end max output.

However, I really don't think you're making good choices for what you describe wanting from the car. 11 to 1 and 383 is going to need good heads designed for sufficient and EFFICIENT airflow for your shortblock, or you'll make far less power than you could, not gain any of the desired benefits, and wind up with a seriously inefficient engine that will give you poor fuel economy.

I'd be more tempted to go for a budget forged 355 and spend on better heads, or if yopu really like the 383 idea, spring for the better flowing (but NOT huge runners) heads you'll eventually end up buying later.

And grammerman... with as few posts as YOU have, you might want to tone it down a bit, because your own lack of knowledge is showing. Suggestion: don't **** off folks you can learn a lot from before you even get started here, MMMMkay?

Oh yeah... a bit more info on other mods would be good, how about you make a sig file?

ABA383

Hey, I'll chime in here...I think he's just trying to build a nice street set up along the lines of what John Lingenfelter used to build...And there's absolutely nothing wrong with that. I ran high 11s with a 211/219 cam for almost 10 years in a 383 with 2.00/1.56 valves in LPE ported LT1 castings...I got 24 mpg on the highway and beat many cars at the track still using street friendly 3.42 gears...That set up could've easily been a daily driver and idled almost like a stocker. It was a great set up...Lots of low end and power to 6000, which is probably why my short block has remained untouched since it was built in 1995!

My latest incarnation is a Joe O. spec'd 226/234 cam (still way weenie by most standards) with the same heads just freshened by E.B. Porting and it went the numbers in my sig thru shorties and in sleeper trim...Again, I've beaten many cars with bigger heads and wayyyy more cam and still get 20 mpg on the highway...With the Kooks and an EWP and Bogarts we expect 11.teens-.20s n/a in a car you could drive everyday...Prelim dyno tests are encouraging...

With all that said I'd go with the 2.00/1.56s and look at the LPE 211/219 or the 219/219 over the Hot cam...I speak for what has worked for me within my self imposed parameters over the last 11 years...Imho theres nothing wrong with building a small cammed 383 with 2.00/1.56s. John knew what he was doing way back before the internet...

--Alan

93redBirdMan

I agree with ABA383. You can have a badass small cammed 383 and be as happy as can be. Dont listen to all these people raggin on you for not wanting a 600hp drag car or something...