F-Bodeee

Hi, i just bought an 87 Trans am w/ a 350, holley 750 4bbl carb, heddman headers, power plus+ intake, and flowmaster exhaust. And i haven't the slightest clue on how to tune my carb to make it perform better. My friend that i bought it from lost to a pretty much stock 85 camaro w/ a 305 TPI with headers, a shift kit and exhaust. I know my car isn't performing at what it should be? What do you think my problem is? I know i have truck heads and a stock cam so is that it? Thanks

F-Bodeee

2

five7kid

iTrader: (14)

Most likely it doesn't have anything to do with the carb.

What's this 350? Did it come out of a mid-70's truck? What cam does it have? What gears? What Holley exactly? (there are quite a few different 750 Holleys)

Too few details to say whether you need to tune the carb or not.

F-Bodeee

Im not sure what kind of 350 it is, i do know it has forged pistons and roller rockers. The cam is stock, it came with an LG4 and its 5 speed so it has the stock 3.23 gears. The carb is a holley 750cfm 4bbl Vaccum secondary w/ dual feed. Model 4160. http://www.holley.com/HiOctn/ProdLin.../0-80508S.html . Hope this helps, thanks

five7kid

iTrader: (14)

Most likely you're suffering from a lame cam and horrible heads. The picture looks like centerbolt covers, so the heads could be most anything.

Roller rockers, or roller lifters?

Any idea what the ignition is?

F-Bodeee

ya, that's what i thought.....the ignition is stock, but i do have an accel 200+ box i want to put in. I believe they are roller rockers.

f-crazy

iTrader: (-1)

be carefull about how you describe the rockers...there are stamped steel non roller tipped (OEM)..there are roller tipped and there are full roller rockers...

OEM and roller tipped rockers use the adjusting nut/ball fulcrum type..thats were you have to adjsut lash and that stuff...TRUE ROLLER rockers use a needle bearing fulcrum type pivot...meaning you torque the nut down and you do not adjust lash...the body itself is roller and the tip is roller...

more then likely you have stamped steel roller tipped rockers...


and i also agree with 57...that cam was LAME in a 305...and now its in a 350?....thats like putting a Dominator on a 9 to 1 street motor lol...

pull off the valve covers and write down the casting numbers off the heads....

im thinkin that your buddy took out his 305 and put the cam and heads onto a 350...in which case, the C/R was bumped quite a bit and the CAM isnt helping any

NEOMASTERZ28

i whould be that 85 z28 he is talking about hahaha

GOFASTER

Remove the heads, take them to a flow bench and check the CFM on the heads. Maybe even replace them with some nice after market heads (alum) and some 1.6 roller rockers from crane, then check that cam, remove it and match it to the new heads and match that to the carb. I would think after that, no stock 305 TBI camaro will take you out in a race.

Also, summit makes a great HEI cap, roter and coil package for around $50 which makes about 50,000 volts (almost 13,000 volts over stock), combine that with some MSD 8.5mm wires and an MSD 6AL box and your smoking!

F-Bodeee

turns out i did beat that 85 z28 anyways.......i'll get heads and a cam later when i have money.....for now...it's good, thanks though

thirdgen88

Ummm... since when do you not have to adjust lash just because you have roller rockers?? Its still a SBC...

NEOMASTERZ28

turns out also u raced me when my car has a prob, but when its fixed weeeeeeelllllllll see

Kontrax

ill race you

yes dude, you need a cam and head work badly. i have a smaller carb then that and i have MANY more mods... could it be you carb is too big?

Kontrax

hey five7kid, remember me? i have a question about the manifold discussion we got into last year. hope we can chat soon

Pablo

iTrader: (1)

haha dude what are you smoking?

your car could have a number of problems. I would start with the simple stuff first, like, is there a miss? What is the timing set at? is the distributor a mechanical advance unit or is the old electronic job still in there?
etc etc

the car should run decent with the parts on there. If the carb is new then I would look at your ignition, timing, etc and general tune of the engine. This sort of thing can be really simple and in a few minutes with changing something simple your HP can jump by 50 when something is not right. Ive been there.

Kontrax

agreed. you might want to take your car to be tuned. they always manage to find some way of popping out more HP from what you already have.

eric17422001

As Pablo said, check other things. Even with a mismatched cam and heads, it still shoud run better.

My S10 (in sig) just seemed to have gradually lost power, and at the same time I noted my starter was having heat soak problems, hard to crank when hot.

Well I'm glad I decided to check my timing one day before I bought a new starter because the advance mechanism in the HEI had stuck, and wasn't giving it enough advance on accelration and too much inital cranking.

A few seconds of working it back and forth and a shot of WD 40 and I had more power than I'd had in months!

Lesson? Check the basics before you start thorwing stones (and $) at other components.

Eric

f-crazy

iTrader: (-1)

Let me clear this one up a little...for roller rockers to adjust them youd tighten the nut untill 0 lash is acheived...then torque the adjusting nut to 18 ft lbs....(crane gold race/ LT4 rollers).so your not adjusting it 1/4-1/2 turn, like a non roller rocker, rather you tighten the nut to a specified setting

thirdgen88

That is wrong... Now maybe you are talking about torquing the little allen screw inside the poly locks that you'd get with your roller rockers after you are done setting the valve lash... you still have to set it to 0 lash + 1/2-3/4 turn. If this isn't what your talking about, tell me what magically changes because you have roller rockers as opposed to standard ball-pivot rockers (the hydraulic lifter along with the adjustable valve train on a SBC doesn't change)??

PS: torquing your rocker adjusting nuts to 18 ft lbs (especially with poly locks which don't have a pinched thread design like the stock nuts do) will simply bottom out the plunger in the lifter and set your valvetrain up for self destruction so don't do that!!

GOFASTER

I am not even going to go there, if you cannot figure out why he should take his heads to the flow bench (or if you even know what that is) I am not going to waste my time informing you.

Listen, do everyone a favor, I am trying to help, don't put crap like that, this board is to help others, not get down on them over stupid crap.

What am I smoking, what a joke!

Dude, take your heads off and get them tested to see if there killing you or helping you, anyway you look at it, you need to figure out where you stand with the current heads, then go from there.

86WS6_T/A

Wouldn't it be easier to pull off the valve covers, write down the casting number and then use the power of the internet to tell you the flow numbers?

Pulling the heads off to have them flow tested is the LAST thing you wanna do. Don't waste your time...

86WS6_T/A

:werd:

GOFASTER

Yeah, unless you want to loose every race, yeah, leave them stock heads on and never get them tested, or ported or upgraded, yeah, some waste of time.


Don't worry about what this guy is saying, your performance will improve with a better understanding of your head flow. Yeah, you can pull the numbers and get an idea of what heads you have for sure, howver, I ma sure you going to be disipointed with them, so get them checked and more than likely toss them in favor of something better.

Waste of time my a-s-s

firbird

i think pablo is on to something, joke? what joke?

CbraKlr88

youre not just putting the cart before the horse youre running the horse over and shooting its dead carcass

KISS (keep it simple stupid) check all the little things first applies to many things in life, this problem is one of those things.

GOFASTER

Again, bottom line is, he wants to win races, that means replacing the dead heads.

Do what you wish, but if you want to win, heads will be a good place to start.

PS I am not giving any of you advice, just the guy who posted this topic, so drop it already. If he does not like what I am saying, then let him tell me, however, I don't see that being the problem.

The problem is most of you cannot afford heads, so you try to tell yourself "it is something else" and skate your way around the problem (s). If he has the money, then replace them, if not, then skate around it and do it half a-s-s. I think doing it right the first time is a whole lot better.


OUT

five7kid

iTrader: (14)

Actually, he started by asking about carb tuning, not how to win races.

An actual flow test on heads is rarely good money spent when you're talking about a mild street package. "Truck heads" tells you about all you need to know, although casting #'s would nail it down. Unless these "truck heads" are Vortecs, it's fairly safe to conclude they're flow-limited without actually performing a test.

Plus, it usually is "the basics", rather than non-tweaked-out port flow that makes the big differences.

And, "I know my car isn't performing at what it should be" is hardly quantitative data. Time slips or a dyno sheet would be much better evidence to support or refute that observation.

BTW, a vacuum secondary carb generally isn't the best choice with a manual tranny.

GASGZLR

I have that same motor in my 66 chevy truck. It is out of a 87-95 TBI truck the cast number should be 10054727 if it is a canadian block and 14093638 if it is anything else. The heads are number 193 72 cc swirlport L05 heads, the motor IS an L05. Mine runs good maybe you should get the timing checked. PM me if you have any questions on how to make it into a beast.

Pablo

iTrader: (1)

Hahaha do I know what a flowbench is hahahaha