hey guys i wanna hit the 12s in my camaro on MOTOR only.

my current setup is a 350 bored over to a 355
-edelbrock cam
Cam Style
　Hydraulic flat tappet
Basic Operating RPM Range
　1,500-6,500
Intake Duration at 050 inch Lift
　234
Exhaust Duration at 050 inch Lift
　244
Duration at 050 inch Lift
　234 int./244 exh.
Advertised Intake Duration
　308
Advertised Exhaust Duration
　318
Advertised Duration
　308 int./318 exh.
Intake Valve Lift with Factory Rocker Arm Ratio
　0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio
　0.510 in.
Valve Lift with Factory Rocker Arm Ratio
　0.488 int./0.510 exh.
Lobe Separation (degrees)
　112

-flat top pistons
-stock 350 heads with minor porting
- air gap intake
-600 cfm edelbrock carb with 6psi
-summit race pump
-stock rearend and gears. going to be putting 3.73 or 4.10 gears and posi unit.
street tires 295/60/r15
any suggestions? i have a nos sniper kit but i dont wanna use that to get into the 12s only to go faster. any ideas or constructive critcism welcome. thanks guys
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What's the car running in the 1/4 now?

 

last time i took it the tranny was messing up and it ran 14.7 kinda pathetic i thought

 

Hows the tune on this motor? Its got a big enough cam that it should run quite abit faster than 14's

What stock 350 head castings are you using?

 

That cam's gotta go. Why do people keep wasting money on that thing? Seems like EVERY TIME somebody posts on any message board for any body style of Chevy, and they have that cam, their car is a MAJOR disappointment... like yours. High 14s is ... yeah.

"Stock" covers ALOT of territory in 350 heads. What heads are they? (casting # ONLY please)

Carb is kinda small and not "the fastest" thing in the world regardless. But I wouldn't just *****-nilly swap it out just yet, until other things are improved.

Gears and converter always seem to help, when appropriately chosen. 3.73 should do it.

Any traction problems? What's your 60' time and your mph? What's your exhaust?

 

ill have to look for my slip. i have a 3000 stall convertor on the trans, it likes to spinout alot when punching it even after using the burnout box. head number 148635365

 

but cant find that number anywhere online

 

No surprise really... not a head casting #... those have 6, 7, or 8 digits. That one must be some other # from something.

Get us the casting # and we'll see what we can do with it.

What's your mph and 60' time?

 

I GOT it off the front of the head. where else can i look for it? i cant find my slip think its in the garage, but io believe the mph was between 86-90 mph..sucks

 

under the valve covers, should be stamped on the head somewhere in there.

 

Right: the factory doesn't put their #s there.

Probably the machine shop's work order # or something.

Look where Orr said. In amongst the rocker stud bosses.

 

 

Those heads seem to be 350 heads off a 1980 motor with 1.94/1.50 valves and 76cc chambers.

I would guess fairly low performance smogger heads but better than 1.72 heads. I am not sure they would flow all that well above 5000 rpm. I would look into what performance potential they have and maybe look into a set of better flowing heads.

 

I would definitely look into a different cam, a bit larger carb, and get a better flowing set of heads with a smaller combustion chamber. Get your compression up to about 10.8:1, and run better fuel. That cam IMO has way to much duration for the amount of lift it has. Look into CCA XFI cams, they have been releasing some pretty decent grinds lately.

 

Obviously better heads and more compression will help here, but I think a big change can be made with a different cam and carb. I assume by air gap you have a performer RPM type air gap intake? That should be plenty.

With those weaker flowing heads, i'd try a much more aggressive cam lobe like a modern Voodoo grind from lunati or a XE grind from comp cams. XFI lobe could work but tighten the lsa up from 113 to a 108-110 perhaps. Something along those lines. Duration can stay in the high 220's range to around 230 deg. i wouldnt go more than that. Even with those heads, I would think it has a high 12 in it with 3000 stall and those gears on slicks on stock suspension.

 

Your compression is down in the 8s with those heads.

Those have to go, along with the cam.

Both of the cam suggestions above would give you something modern, competitive, and far more suited to expectations of today's builders than that relic from the early 70s you have now.

Look at heads in the 60-64cc range, with ports in the 180-200 area. Dart or AFR would be great. Even Vortecs would be a MASSIVE upgrade from the smogger low-perf truck garbage you have now.

You're not going to get from 14.7 to 12s with a cam and a carb. You're barely making 200 HP now, and you need near 400. Time for a MAJOR re-think.

 

ya i have the air gap style intake. i know i should be in the mid 13s with this motor. at the track i had no grab with the tires and the tranny acted like it was in neutral 3/4 of way down track. i was ahead of a car till the tranny missed that ran a 13.5 so im wondering with gears,slicks,and tranny dialed in i should be pretty close to high 12s even 13 even

 

i found the correct head code. my paperwork was for my old 350 the ACTUAL number is 3947041 sorry guys

 

Those would be about same as the 186 heads. Apparently these were on 69-70 300hp motors. Not a bad head for a factory casting. 1.94 valves and 64cc chambers so you have ok compression.

Should definately support a high 12 second pass I would think. You dont need much head to get into the 12's. I've been there with stock L98 heads which aint much better than factory irons from the past.

Have those heads been worked on before? They likely dont have hardened exhaust seats for use with unleaded modern fuel.

I'd upgrade to vortec heads if you can. They are cheap and easy to get, then just use vortec air gap rpm style dual plane intake. Abit more modern cam and you should easily have mid 12's. My buddy's 83 shortbed chevy truck went mid 13's at 99 mph with just LT1 cam in a vortec headed carbed 355. Basic motor. Bit more cam and lighter thirdgen camaro, it would go high 12's easily.

 

how much lighter do i need the car to be? i have no rear seats, radio or heat controls, heater core removed, all a/c and smog removed, and procar race seats. im not looking for a speed rocket but my goal is to have a 12 sec car and be happy with that and play with the bottle if i wanna go lil faster..

 

Have you weighed it? you probably are light enough as it is but your performance so far is indicating far less than optimal power. Even assuming a bad cam and heads combo, I think there is more in your setup with some fuel and timing tuning. Really should swap cam out since flat tappets are pretty cheap these days. Retune and see where that gets you. Also make sure your tranny is working right and not slipping. Also need to have traction.

 

i have the timing base at 10 and i think 34 total, should i bump up timing? i also have stock ign and the d.u.i distributor cap and coil. taylor 8mm wires with ac delco plugs gapped to 35. is my fuel psi to low set at 6?

 

No, you should leave the timing alone, and find out what your motor is built out of.

So, what's the number ON THE HEADS?

This is the 3rd # you've thrown out there so far. While I'm not one to call someone a liar or even lazy, it would appear that the time is long past to get up off the keyboard and LOOK AT THE HEADS.

What's cast into them, is what's cast into them. Sounds like the rest of that is .... the rest. Sort of like that fake bogus stainless braid some people put over their wrinkly universal radiator hoses and such, hoping to fool casual onlookers. But as they say, the bulls*** stops when the green flag drops.

 

i

 

this is the correct number 3947041! i physically went out and looked when the last number didnt make sense from being off a truck. thanks *******!

 

call me lazy, and a braided line cover up?

 

Silly question, but what's your full slip for this? Notably MPH at the 1/4 and 60 foot. If you're spinning you're losing out. Not only that but what was your "transmission issue" you mentioned? Could be making power but not putting it out the back wheels in a useful way. With as much duration as you have if you have 76cc heads you could need more compression to make that cam work as well.

 

Exactly...whats the rest of the slip look like. I would say you need to first get a clean pass with that combination to see where it is before making changes. Although a cam swap at this point could still be beneficial but wont matter if the tranny is missing shifts or slipping or what have you.

 

the issue i was having was itll take off in first to second and as it hit third about 5000-5500 it would act like it went into neutral. i noticed when i put new intake on that the plastic cover over the throttle cable was hitting the bracket not letting it go full throttle so im hoping that was it. it spins out alot with the reaend i have now i mean like 130 plus burnout marks....

 

true with the setup part. i just installed the new intake and stuff so ill have to wait for rearend next month and giver a shot and see where i am at.

 

700r4 trans? Is 3/4 clutch pack going out and causing it to slip? Right before my tranny failed, 2nd gear started to overrev and wouldnt shift to 3rd then when it did, it was slipping hard in 3rd. Lost 4th gear then lost 3rd a few miles later may be time for a rebuild.

 

sucks i just had the dang thing rebuilt last summer. also whats a good posi for the rearend i have in my car?

 

Until you break 350 RWHP your factory posi will be fine on street tires. I'd definitely run 3.73's though. Since yours in an 84 though, with the weaker 26 spline axles, you may want to upgrade to the later style 28 spline axles found in the 89-92 models. If you want to run drag radials or slicks, I would definitely think about upping to a 12-bolt if you get near your 400hp motor.

 

i currently dont have a posi unit. it got a limited slip and it always does a one wheel wonder peel. were can i find a 12 bolt to bolt in?

 

Limited Slip is the posi that came with these cars. If you do a one-wheel wonder, then you don't have a Posi.

To get a 12 bolt, you'll need to get one specially made, Moser and Strange both sell them, but your'e looking at $1200+. Your best bet would be to pick up a unit out of an 87-21 GTA, those were the stronger 10-bolt rears and had posi.

 

whats a good timing setpoint for a 355? i have it at 10* base timing. will this work?

 

Have to keep playing with it to see where it wants to be. On the EFI cars, 20 deg of timing can be see at idle. More timing usually gives abit more stable idle and higher vacuum but too much can be bad as well. With a carb I guess 10-18 is ok depending on the cam/heads combo.

 

ok found my time slip. my reaction is .1061, 60ft 2.2754, 9.6049 1/8 e.t at 75.23 mph, then 1/4 15.14 at 84.05 pathetic

 

I would have to agree with what everyone on here is saying, but first thing I would do is get that trans looked at first before replacing the heads, cam, carb and gears. Eventually you may need to do this, but if the trans is going, then nothing you put in it will work with the trans going out.

 

My 355 is set at 8*, but it's carbed and set before with the ECM unplugged.

 

WIth those heads on that motor, youre lucky if your getting 8.5:1 compression. Those would be the older smogger heads and a good port and polish would go a long way toward helping. the 1.94 intake/1.50 exhaust isn't bad, in fact that's what the 305 heads get ported to to make them performance. You could up it to 1.94/1.60, whichis what the newer Vortec heads are. However, to bring the compression up, youre going to need to run some good flat-top pistons.

You want to run 12's, you're going to need a minimum of 400 brake horse power (At the flyhweel) and 350-400ft-lbs of torque to even have a chance. So, it's possible with a 355, but I think your motor is going to need a lot of work.

Might be better off keeping what you've got, upgrading your suspension, transmission, brakes etc, then when that's all done, pull the motor and stroke it to a 383 or build a 400. That will get you to your 12 second 1/4 a lot faster and probably cheaper than you can do right now.

 

after putting a new air gap intake on i noticed the plastic sleeve that the throttle slides thre was hitting the bracket and not letting the throttle open all the way. i say maybe 1/2 inh was not being allowed threw. would that make tranny act up? i just got my posi unit, with 3.73 gears, 28 spline axles, new ms plug wires, msd 6al box, and accel u groove shorty plugs. im hoping that this will help me out allitle bit too

 

You did get a posi unit to match the 28 spline axles right?

For the throttle cable, it would only affect the tranny if the cable for the TV adjust was binding as well.

The rest of it is good for a good tune up. I mean that unless its really messed up, I.e. plug wire causing a misfire, you may not directly be able to sense a change in performance, a dyno would show it though.

 

i got the 28 unit to. my plugs were really black and 2 were brown on the tips, dunno if that helps anyeither

 

If a couple were bad and you were at all worried about it, then you did the right thing by changing them. It all helps. I just think you've got a long way to go to get where you want to be. I know you say you want to hit 12's, but I think it best to get all the supporting items there first, like you've started to do. Upgrade the rear-end, upgrade the suspension, the bushings, the brakes, the transmission. Once all that's set, then the motor. Trust me when I say, all the rest of it will make the car seem faster, and it will probably run faster as well. I know upgrading the suspension on mine with my 305 on it made it feel a whole lot faster and gave me better handling as well. Keep us up on how things are coming with it!

 

but if the sleeve isnt ratcheting out, the kickdown wouldnt extend all the way, correct?

 

been awhile since i updated on my goal for twelve seconds. i got the posi installed with the 3.73 gears, got drag radials, new th350 tran with 2800 stall, aluminum heads 2.02/1.60 valves, 650dp holley carb, and still got cam. hoping im getting closer to the 12 mark

 

It will still shift. It may shift earlier, but it will still shift.

You've got some serious issues in your combination. Something isnt right for you to be trapping at 85mph. If its the trans that wuold make sense. That old relic of a cam should still do okay if you're in the low 9s for compression. You'd be better off with a newer design, and get better street manners, but it should still be putting out at least 250hp I would imagine and you're 50 down from that.

 

i replaced the tranny with a th350 i bunt up the clutch packs in the old tranny. so that issue is fixed

 

What kind of "aluminum heads"... what exactly are they.