ok well im taking my '88 rs camaro v6 fi to a v8 carb, im told that i nd a carb with atleast 650 ctu? since i hav a/c, so does any one now what i should even start to look for in a carb, or recommend wut i should get? i plan on taking the electric pump out, putting in a new line, the engine has a mechinacal pump, and do i nd one of those fuel pressure regulators? the engine is a stock 350 with a few hihg preformance parts, new race cam, pitted pistons, and some others, i bought the engine as is so im not sure wuts all in it, but i do now its all working. any help is much appreciated.

 

So your new motor has new pitted pistons huh? New high performance pitted pistons...thats hilarious!!! Where can I get some?

 

lol ik i thought the same thing, but hey, just come to roanoke, va go to a junk yard n look for a truck with a 350, ask wuts wrong n when they sai i dont now, u got a good engine, i bought mine n the only thing wrong was who ever rebuilt it didnt put oil in it b4 they ran it lmao, but the only thing wrong was 2 spun bearings, but i kid u not, they r pistions that r pitted, and 4 hav numbers, the other four hav letters, ill get some pics up soon

 

What you see are probably valve relief pockets...do they look like this?

 

ummm not really no, there r 4 pits on each pistion, 2 at eighter end, then the number/letter is in the middle, kinda looks lik where the spark might hit, please b easy on me im somewut a noob at this part on cars

 

I would like to see pics of those pistons...anyway back on topic!

Since you dont know what cam you got or any of your other specs I would go with a quadrajet...maybe a Jet stage 2 quadrajet!

http://www.jetchip.com/products.asp?pid=23033

 

sure thing, when i get my camra ill defently put some pics up, n ty for the recommdation, but would there b a way i can check the specs of everything, to get a more perfect carb for my engine? i mean it came out of a truck, n i do now the engine was rebuilt with parts for more horsepower to tow with...

 

Good luck with your project. Perhaps because I'm an old fart, I find reading your posts very difficult. Something closer to standard English would be helpful.

JamesC

 

lol its ok james, and thanks, ill try to clear it up, i bought this motor that came out of a truck at a junk yard, i now it was rebuilt with preformance parts to increase the power of the engine. i was just wondering if there is a way to i.d. these parts and get the specs for them so i can choose a better fitting carb for my engine, the engine is a 350 that came out of a 80s chevy scottsdale

 

Okay, let's try to clear up some terminology.

"CTU" - no clue where that came from, but carbs are typically referred to by the "CFM" - cubic feet per minute - they will flow at a given vacuum. 650 CFM is a pretty typical size for a 350 engine.

"Pitted pistons" - there are pistons with valve reliefs (two shown in the picture posted, most stock type have 4 so you can put the piston on either bank of cylinders), and dished pistons - some have both a dish and valve reliefs. There are also domed pistons, and the 283 originally in my '57 had flat top pistons - no reliefs, dish, or dome. Most likely you have what are typically referred to as flat top pistons, which have the valve reliefs so the valves don't hit the piston when the valves are opening near the top of the piston travel.

"Towing power" - not really what we'd call "high performance". "Mild" is more like it. Without knowing the brand and part numbers of what when into the engine, it's almost impossible to say what they might be. You could try posting the numbers you see on the top of the pistons, I'd guess one of them is "30" or "030", meaning they're .030" oversize, which is a typical rebuild size.

Knowing what heads are on it would be helpful. If the engine came out of a 80's pickup, they also are not what we'd call "high performance". The best way to determine what you've got is to get the casting #'s from them, located between a couple of valve springs. Get them both, because you never know what's happened to an engine that's been in a junk yard and/or rebuilt.

The intake manifold would be another good thing to know. Is it stock, or something aftermarket? If stock, the quadrajet is probably all that will mount to it without an adapter. The q-jet is a good choice for street performance, anyway.

I wouldn't remove the in-tank pump unless there is something wrong with it or you don't want to mess with the wiring to keep it running without the computer. You only need a regulator if you keep the in-tank pump. If you remove the in-tank pump, see the sticky in the top section of this forum about making a carb-type pick-up.

 

ok tyvm five for clearing things up for me, looks lik i got some i.d. numbers to pull i will post them up, but is it in this tread? or do i start a new one somewhere else? i htink mayb in this thread so i can figure out with carb to get

 

Continuing this thread would be fine since the ultimate goal is to answer a carb question.

 

ok well lets see monday and tuesday i will be working on my car so ill ge tthe pics and numbers then, gotta do some routine maintain, and replace a heater core, o what fun this auto shop has caused me

 

im not sure what your power goals are, but I have a holley 670cfm double pumper car from the Street Avenger series on my daily right now, and am very satisfied with it's performance and easy tuneability.

 

Uh, "670" and "Street Avenger" go together, but not with "double pumper".

 

well my power goals r somethin in mayb the 500 to 600s, i think, i just need so show up the mustangs and all other rice griders

 

500 to 600 what?

 

http://www.jegs.com/webapp/wcs/store...49689_-1_10271

 

No Street Avengers. Please.

 

500-600.. hp? I think you should consider something a little more reasonable.. especially since you're trying to do it with a junkyard 350... unless you got really deep pockets..

 

if you're making 500-600whp like my built car is, mine runs like a champ on an Edelbrock 850cfm. if you're using a stock 350 just go buy a holley 570cfm or a remanufactured quadrajet with larger jets and whatnot.

 

edelbrock carbs = crap. Is that 500=600 dynoed hp or 500-600 in the magic world of your mind hp?

 

Like Five7 was saying, we really do need to know more about what components the engine is being built with - mainly what cylinder heads (need the casting number), and what camshaft you are using. Those are the two critical specs.

Now, that said - I have a 350 that started out very mild as a 180hp wonder, and have built it up over time and it makes around 400hp now. I've used a 750cfm Vacuum Secondary Holley (PN 3310) on this engine since the beginning, and I really like this carb. Its been very trouble free once its tuned right, and its a very streetable carb. Electric choke helps it start up easy when its cold out (even at -40*C) and it runs really nice just under normal driving conditions and makes alot of power at full throttle. Very responsive too.

I would highly suggest the Holley 3310 for your 350. Even GM used that same carb on lots of their high performance 302, 350, and 396 engines for a number of years.

 

you talking about him or me?

 

so you mean you have a flat top piston with reliefs for the valves in them

 

I was asking you, maybe since you two have similiar goals you could let him know the secrets of your combo.

 

The secret is probably the blue bottle under the hatch.

 

wow you guys are funny, thanks for the laughs, and ofcourse the help, lik i said ill be getting pic probley tuesday, and i do believe they are flat tops...and yes i waz thinking mayb 600, but that is to much for , hehe to much fun means to many tickets , cops dont lik me as is, something bout my siverado beating them in races, i dont know, but anywas the holley 3310 sounded good, but im still looking and id my parts, i do now it will be getting a supercharger tho

 

im estimating myself to be in the 500whp range, but who knows until i nail down some dyno time this weekend. ill give you all my numbers, on motor and on spray.

 

A 600 won't be too big now (forget the 3310 - no reason for that carb), but you'll need a different carb for the SC, anyway.

 

ok well i got some pics but my camara must of not liked them bc it deleted all of them, so the numbers i found, please bare with me, i dont now what numbers hwere needed so i got every number i could find, so ill try to put into words where they are...
# on fuel pump area 33 (its a mechinacl pump)
the things that hold the crank(forgot the name of them sorry)
front: sideways f 3951
GM668
second: side ways f 3478
GM13
third: same as above
rear: side ways f 3412
GM25
# number on block above oil fliter: 010
020
5
block number im guessing, GM 35 3970010
number on other side from ^ B206
then there is a pic of dots in a circle with a t at one point, n at another, n c i think at a third point, that is between these 2 numbers ^^

now the pistons, the "pits" make em look lik spiders and they all hav number/letters on thme, the letters in the middle of the pistons are j,j,j,j,i,h,g,g, then on the pistons there is random letters/numbers at random loctaions that im not even gonna attempt to list, pics would just be easier

sorry for not haveing pics, ill try to get some but hey atleast i found all the number on the block, lol

 

Go check you numbers at www.nastyz28.com I would get a holley carb they are easy to tune and just good carbs. What are your plans for this car and what kind of tranny do you have?

 

1. A motor built for forced induction is going to need lower compression than a NA motor if you want it to lost

2. 500-600hp is ridiculous and not streetable. The only way to make it work is with forced induction, in which case a junkyard 350 with mystery heads and a mystery cam are not going to wrk.

3. You need to get the casting number for your heads.


Do you see the numbers between the guideplates? You need to pull your valve covers and write down the number.

Yours heads and cam will determine your power.

 

an 010 block is one of the most common castings out there, its a flat tappet 350 block with 2 or 4 bolt mains from the 70's.. not a bad starting point..

 

ok well my plans are to have increable amounts of power, lol 500-600 is to much, i relieze that now, i just i jumped the gun on that, but a reasonble amount over time would be nice.

i bought a t-56 tranns

and the enigine is apart but covered in gunk, i guess it is from the 70's, but ill try to get the head numbers, but how do i find out what cam i have?

and ty 89rspower, i hav hope now

and besides just b/c its a junkyard motor doesnt mean it can b the best thing...all it needs is some cleaning, whihc im don, and a real mechinic, lol, but really just someone who can build it correctly, me wiht the help of all YOU!

 

500 flywheel HP is not unrealistic for a street engine - definitely for a driver, but not a weekend toy. Just get lots of cubic inches to make it. A 400 small block with a nice set of 195 AFR or TrickFlow heads, Vic Jr or RPM intake, 750 double pumper, around 11:1 compression and a cam to match and 500 crank HP isn't too unrealistic, and can be fairly streetable with the right cam. The fuel mileage will be horrid of course, but not necessarily the driveability.

 

Ok, I'll share a little of my trials and experience... You car is a bit like mine..a V6 MPFI converted to run a V8. I also started with a Junk-Yard 350. Mine came out of a '88 C/K 1500 pickup..it currently is off at a machine shop being bored out for it's next life as a Mercruiser marine engine

Current motor in mine is a 400 small block bored and stroked to 420cid with JE pistons, aluminum Vette heads, mild Crane cam, Edelbrock manifold, topped by a Holley 750cfm vac-secondary 4160. I've capped my rpm at 5500..most of my valve train is stock and I don't want to upgrade it yet.

Now, assuming your 350 is a truck/RV motor...a 600cfm Holley will feed it just fine. Figure about 80% VE and a 5500rpm redline on a clean late 80's 350 if you are going to use many of the documented carb selection guides. You could go to a larger carb, but usually that means giving up some throttle response at low RPM due to the lower velocity of air going through the larger throttle bores. ( there is such a thing as "too much of a good thing" when it comes to picking a carb size. )

Now, if you put better heads on the motor, you can bump the carb size up because the VE number on the motor should get closer to 90%...meaning the engine is capable of sucking more of it's total displacement through the heads. Make sense?

 

actually yes, and its is unbelieve how close my project is to urs, but mine came out of c/k 1500 late 70s i believe...now my question is VE? i porbley now what it is, but not the abbrevation...

and i didnt now they made 400 small blocks, if i knew that i would of found one, lol we hav all kinds of engines down here, well looks lik i now what im gettn for my 86 now

 

volumetric efficiency

 

ok thank you, turns out i hav no idea what that means...i am sorry all, in mechinics calss we study fi not carbs...

 

Volumetric efficiency is much more important with Speed Density based fuel injection than with carbs, but back to the topic...

If your motor came out of al ate 70s truck, then you probably need new cylinder heads unless you want to cruise around at 150hp for years.

 

VE, or Volumetric Efficiency is, in simple terms, how much of the motors displacement it can really suck down through the heads, intake, and carb..and also pump out the exhaust.

We all start out with the displacement because it is a hard number that is easy to measure. (bore and stroke define the motor's displacement.) So every two revolutions of a 350 can, in theory, suck 350 cubic inches of air.

In the real world, the motor can't draw it's total displacement, it can only draw a percentage of it..that's it's VE.

You can find the formula out on a number of auto math web sites as well as on Holley's site.

While it's true that the number is important for fuel injected cars, because it is used to compute the fuel on some of them, it is also important to the carb folks too. It's the number that determines the size of the carb your motor will really need.

For example, a 1970's 350 truck motor has a pretty low VE (new) and an even lower number as it wears out. I would guess that it left the factory with a 70 to 80 % VE number, and may be down in the 60% VE a few 100k miles later as carbon builds up on the valves and the wear on the cylinder bores accumulates. If it has those pathetic cast iron emmisions heads (small runners, HUGE combustion chambers, and small valves) It is gunna suck very little of its displacement. Actually, it's just gunna suck (pun intended)...I remember the bad old days of the 70's smog motors.

When you pick a carb, if you use the displacement of the engine converted to cubic feet and multiplied by 1/2 the redline rpm, you will *always* get too big a carb (Not many motors can make it to 100% VE with out some help, like a supercharger to cram more air into the motor)

If you guess at a realistic VE, then you get a carb that is smaller and ends up being better for the motor (doesn't restrict it at redline, yet still has good throttle response down low.)

Now when it comes to making more power there are really only two methods:

1.) increase the engines displacement (get more cubes to work with)
2.) increase the engines VE (make better use of the cubes you got)

Ok, there's a 3rd method: DO BOTH!

 

i am cleaning the motor, i mean it wont be like new ofcourse, but i hav it apart and am cleaning the carbon and everything off


and clm2112 thank you, but whne i took the heads off, they where a lil heavy adn the values looked lik a disent size, but ill be getting the numbers tuesday to check for sure. and how do i find the redline for my motor? do i set it or what?

 

Those heads, if they're stock 70s heads, are going to be terrible regardless of how shiny you get them. You can get some 083s (L98 heads) for $150 a pair without too much trouble. Do that.

Redline is just the max RPM you want to spin it. There are two redlines, one that's determined by what parts you have in it plus some guessing and fudge factoring, and one that's determined by your powerband. In most scenarios the range where your power starts to drop off is your redline since you'll never need to go higher than that, but if the physical limit of your engine is lower (such as if you got a heads/cam combo meant to make power at 8,000 RPMs and didnt get a valvetrain/bottom end to handle that) then... well, you get the idea.

 

thank you and i would kinda lik to keep the redline sa the same as the tac...if possiable

 

ok so i got the numbers form the heads and headers, the heads are 333882, the intake is 346250, and the headers are 346322 rh and 364763 lh, i checked them wiht the one site meationed earlier, not everything matched up...and a lil off topic the headers, will they work with the exhaust, i checked and they bolt right up...anywas thanks for all the help

 

You have to by F-body specific headers unless you want to rebuild the frame of the car and relocate the engine around them... (You dont).

Hedman long tubes are great, cheap option. $150 for a set. You'll have to fab up a custom exhaust system for those though and they dont have emissions crap on them. If you like being able to get over speed bumps go for a 3 inch stock style catback and shorties. The best shorties are Hooker 2055s.

https://www.thirdgen.org/forums/tech...ber-heads.html

You can reuse those heads if you like, but if you can swing for a set of 083s I would go ahead and do that instead. 76 cc chambers will make for very low compression and low power.

 

ok thanks to everyone, so now back to my question, lol, what carb would be good with my motor? or atleast what range should i look in? ik i need a 4 barrel carb, but with 650 cfm? the heads are 083s and the headers are the hookers 2055s

 

Do you want mechanical or vacuum secondaries? Do a search.

 

you have E85 fuel statons within 50miles of you. E85 is app 104-116 octane(jump in here if im wrong) Which means you could buil a 13;1 comp engine. Build the bottom end all forged,, crank ,rods , pistons, and set up now for a good set of nitrous rings. Once you have the bottom end built get a solid cam and a damn good set of heads( not the time to be cheap here) Intake and exhaust are next, but if you want put a blower on it,then you need to start over and change some things.


Try to get a game plan together before you start. It might cost a whole lot less to buy a crate motor, than to build one yourself. There is a place in NC that builds what i was talking about above (with dyno) Ill try to find the name.

500 is streetable.

The big 3 are getting ready to push them out soon.
ford gt500..505hp
dodge challenger 510hp
camaro 515hp

but the major problem is your whole car is not set up to handle it.
trans
rear
brakes
steering/ suspension
if you dont have the sub-frame connectors in you will start twisting the car

There is nothing wrong with dreaming big.