buell_13

I recently built a very respectable 383 stroker, with plenty of power and torque..... but it's not near as loud as my 305 was.... same exhaust setup.... anyone have and idea why?

Guest

My 350 sounds badder than a lot of cars at idle. Not a whole lot to right home about when I get on it though. Some cars just pitter patter at idle and SCREAM when they are opened. So is your just quiet at idle of just in general? What exhaust set up do you have? In all honesty tone and volume can be tweaked mostly by the muffler. What muffler you have? Have you run your 383 to prove it is really "big and bad"? That won't have a whole lot to do with tone anyways but just curious. Tell us your exhaust setup first. If your engine is built propery than it should all be due to your exhaust.

P.S. A 305's exhaust set up won't necessarily act the same way with a 383.

buell_13

I have mid length headers to 2 1/2 stock style y pipe to gutted cat to flow masters series 40.
The car will lift the front tires with stock suspension.... got plenty of seeya later.... just quiet all together.....

1gary

There are guys who spend alot of time to build a"sleeper". Just the kind of surprise for a street car.And oh the black mystery of all that comes along with that.Hehe,tell them all it's a 305 at a cruise night.The wow factor will get them all talking..............

buell_13

I liked the way it sounded, just curious if anyone could point me to what makes exhaust louder or quieter within the motor...... for instance.... if you take a 305 with 9.5-1 and stock cam.... then you change that to 383 with mild cam and performer intake, and pistons that should produce 10-1 wouldn't that make a more violent explosion.... therefore making it louder.....?

Guest

You are correct on the compression ratio making a "bigger explosion". However, if the gases are not released quickly from the combustion chamber, it dulls the sound of the bigger explosion. Your firing order can also affect the volume. That's getting pretty technical though. Most 383's are some of the baddest "chug chug" sounding engines out there so you are in a peculiar position.
Your engine is obviously on the mean side so the good news is it should all be due to the exhaust. The exhaust ports on your heads could also affect this but I am guessing you have some nice heads or have ported your stock ones? If not, possibly try that. You'll also get a nice power gain. Easiest and probably the most relevant:Go 3 inch pipe ALL the way through. I have basically the same set up as you and the power gain was awesome but the volume was only slightly improved. 3 inch throughout really will help.

Possibly ditch the cat entirely. Its gutted so I don't think you'll pass an emissions test anyways.

Bullet style muffler will GUARANTEED make it sound louder.

Might sound crazy, but the Flowmaster 80 series USUALLY gets better reviews than the 40 series. So if you don't want to roar like King Kong with the bullet style muffler, this might be an option. It could take you in the opposite direction though so its really just a last ditch effort.

Honesty, go three inch throughout and i think that will solve it. If you can custom fabricate pipes than try a nice dual exhaust set up and that will help quite a bit with volume and some with power. After that, bullet style muffler.

Guest

P.S. The "sleeper" is not very desirable for most 383 guys. The 383 in my opinion should emit a f*** off sound.

buell_13

Well now that You mention the head ports..... that could be the issues...... that and the mild cam.... if I go bigger cam and ported stock heads.... would that make the change? Also would high volume oil pump cause above average pressure at higher rpms? I want some 461 casting 305 heads but those are proving hard to find..... What dimensions should I shoot for with the ports on stock 74cc 889 casting heads?

Where are you located jayhawk? Near the Dallas area?

1gary

I own a 383..................

1gary

Best case for stock head is 170cc intake runners before you hit water.That's not enough for a 383.10.5 on a case iron head is over the limit on today's gas.

buell_13

So what heads should I be looking for?

Guest

I would recommend vortecs. While I do not run these heads, I have seen what they can do. I don't know of they come in 76cc chambers though. The most common are the 64 and 62cc chambers which I think would be more than overkill for your compression. Of you decide to port your heads, I believe 65cc exhaust ports should do it. Maybe up to something like 72. I just have my heads to my machinist and said GIVE ME POWER. So I am not the most knowledgeable when it come to port sizes. By the way, if you get vortecs you might have to change springs to get appropriate lift. I would recommend porting your heads. It's impressive you can get lift with out any port work. You should notice the power gain.
P.S. I live in Bixby, Ok just south of Tulsa.
Gary: it's weird you like the sleeper affect. You 383 guys always come off as heavy lopers to me.

buell_13

See mine lopes ok..... room for improvement.... but I don't really want vortec heads.... you think a bigger cam and ports is enough? Also any answers to the oil pressure issue stated above?

This is my first 383 and it's amazing... thought about a 427 sbc but too expensive.....

NagleMac

iTrader: (1)

Vortec heads would also mean you need to get the appropriate intake manifold too, I'm also building a 383, but not using stock heads and going with a large cam... But anyways, my 305 was EXTREMLY loud and I loved it, but I'd start with 3inch pipes, you'll like the power gains from it because 383s seem to like lots of exhaust flow and by the way, any trouble with getting those mid-length headers in? I'm thinking of running some on mine

buell_13

The only issue is passager side it's tight with the a c box.... like I broke mine.... I suggest installing while motor is out and two people minimum when you reinstall.....

Sounds awesome open too just sayin......

buell_13

Will a high volume oil pump cause 60+ psi at higher rpms?

NagleMac

iTrader: (1)

They're definitely going to be installed befor the engine is mounted, if you want to try a different muffler try a thrush 2 chambered welded muffler, for $70 you can get one that will fit the stock exhaust with 2.5 inch inlets and outlets. Hell, you can have the one off my camaro for $30, it's only a year old but it won't work with the exhaust I'm making for the 383, it's only got like 5,000 miles on it and sounds amazing

NagleMac

iTrader: (1)

I'm not entirely sure, it's possible

buell_13

I like the exhaust I have it's super deep..... just not as loud as I thought it should be..... but I am gonna put 3" in asap..... true duals at that..... just watch your ac box mine was super brittle..... oh and your wiper cover..... it's in a dangerous spot.......

buell_13

Something is causing 60+ psi at and above 4500 rpm

NagleMac

iTrader: (1)

You should see some nice power gains from the larger pipes too, and I'll definitely watch out for those, what brand are yours?

NagleMac

iTrader: (1)

The oil should be hot and thinning out by then, meaning lower pressure

buell_13

Right, that's what I figure but it's not when I'm running about 50 I'm fifth it's roughly 40psi

I have no clue the brand on my headers..... just some given to me.... but get big tubes....

NagleMac

iTrader: (1)

But actually at that speed it should be higher, maybe you have a blocked oil filter or you're using the wrong grade of oil, or an oil gallery is blocked, but I think there is a relief valve to keep the pressure down at high rpms

NagleMac

iTrader: (1)

I think at that rpm with the higher pressure pump that 60+ could be where it's supposed to be

buell_13

I think instead of it being a high volume pump it's a high pressure pump..... and the parts store messed up.

NagleMac

iTrader: (1)

I wouldn't worry about it, I think it's normal to be that high

buell_13

The only thing that bugs me is when I step on it..... it pegs out.... but I have heard some motors especially tight motors like mine That only have .001 clearance produced up to 80 psi oil pressure.....

spicyskater

if its more quiet with the same exhaust means the engine works better than the one u had before

NagleMac

iTrader: (1)

Im going to disagree with that, but do you have a reason why you think that?

buell_13

Uses about twice as much fuel though..... I've got the carb adjusted as best I possibly can too..... but my mileage has severely dropped I knew it would drop but didn't think it would be That bad....

NagleMac

iTrader: (1)

A carb on anything won't get good mpg

buell_13

With that 305 and the same qjet I got 25 city, 28 highway..... pretty good for carb

But now it's less than ten, city or highway stays the same.....

buell_13

I want a tpi but don't want to try to piece it but together.... end up with wrong injection pressure and torch my pistons...... and finding a full system with ecm is very difficult.....

Guest

Naw you're fine with the carb. Takes a lot in a too to make it pull like. Carb up top. As far as your psi goes I see more of a problem in your fuel regulator than your pump. The pump itself won't do anything without the computers permission and the regulator is controlled by the ECM. If you are a DIY tuner than just go and look for some advice on where I'm your coding you need to change the parameters.

Guest

A tpi not too

Savage388

something isnt quite right with your mileage, I get almost 20 on the highway and at least ten in the city. Well if I stay out of it.

buell_13

I like my carb just tired of adjusting it..... lol need a new one with all the goodies inside.... like shorter accelerator pump bigger meter rods.... all the high power stuff......

buell_13

I've adjusted everything I can.... it's running great just sucks down the fuel.....

Savage388

What carb do you have on there? If its a mechanical secondary that will hurt mileage, but I still dont see less than 10, thats big block stuff.

buell_13

It's a qjet with mechanical secondaries.... I think it's adjusted wrong but if I change it my throttle response vanishes......

Savage388

Im no carb guru by any means but those mech secondaries hurt you and it does sound like you either need to replace it or a good rebuild. Like I said it is possible to get reasonable mileage with a built 383. Personally unless you race it more than you cruise/drive it id get something with vacuum secondaries.

buell_13

I've also heard that the electronic advanced hei can cause issues with mileage.... I've heard that a vacuum advanced distributor is better..... what makes the vacuum secondaries better?

1gary

Gots to make up your mind.IF you really want performance then your thinking has to look at aluminum aftermarket heads and a intake runner of 195cc or better with a solid 10.5 compression and a cam/t/c,rear end gears to match that.If you want "the sound of it",then your going to hang some rag tag exhaust off of it and "pretend in what ya got in a mind game". You see I am not big on what does it sound like,but more on the result of the performance is sounds like.....

The carb is like a toilet with floats and all.MPG will always be better with a EFI.

Your question about a high volume vs high pressure oil pump involves how many miles you have on a fresh build for break-in.Have you done your first oil change yet??. Are you still running the break-in oil in it??. I don't like high volume pumps on the street because of the possibility of not having enough capacity and all the oil is in the overheads not draining back fast enough.The question of high volume vs high pressure oil pumps on the street is a age old debate.For me the high pressure pumps is the way to go with a pressure relief at about 70 psi at cruise speeds.I want to throw in here for yrs I was a committed Fram user.God knows how many over the yrs we built street engines with that in use.I read a review on oil filters and cut open one myself.Bottom line is they are cheap junk.We made the move to Wix filters and are very happy with the results.Guys have made the move to synthetic oils,but I am still old school using a multi wt Pennzoil mainly because 0 failures,so if it ant broke why fix it??. The other logic is I sure didn't build a engine and then want to see how long I can go without a oil change.

The idea of Vortex heads coming up all the time is a crutch for not applying the theory of a correct head runner/cam to a given c.i. engine. Then following that through with a good t/c and rear end ratio.What makes Vortex's a Vortex is the rough surface of the intake runners and then guys talk about porting them which destroys the Vortex effect.Porting the exhaust side??. Sure that works.The intake side??. Nope.Cheap investments reap cheap net results.Seems kind of silly to go through all that money to build a stroker and then cheap out on the top end where all the power is made.

Mpg??. Read your plugs.I'd bet money the carb isn't showing you any love back.

Savage388

Someone else can explain it way better than me but what basically happens is only heavier throttle inputs will open up the secondaries and if you drive carefully you can see better mileage by reducing inputs that create vacuum,ie being smoother on the throttle, lower rpm shifting. With mechanical secondaries no matter what you do they'll start to open at a certain point whether you need them or not reducing gas mileage. As far as ignition I am certainly not the right guy to ask .

1gary

Gas mile,just a additional thought.That is more(power) is less and the rest is up to you.Your the one who manages the gas peddle/driving style.

buell_13

Also my has gauge reads about 1/4 less than actual.... that is assuming it's a 14 gallon tank.....

buell_13

Any ideas about tuning the carb, if I'm not mistaken I have the idle jets 1 1/2 each..... also the air bleed is shut completely.... and not sure about the high idle..... don't have the tool to adjust it.....

1gary

I'm confused.Are you running the EFI electronic dizzy with a carb??.

buell_13

What did I say to confuse you? I have an electric q-jet, I have adjusted the idle jets to 1 1/2 turn each, and the air bleed is closed.... I am not able to adjust the high idle due to not having the proper tool.....