i just built a 350 with vortec 062 heads, about 10:1 compression, rpm intake, crane 282 energizer cam(226 .050 duration, .470 lift, 106 lsa). its got an edelbrock 600 cfm carb and a set of flowtech 1.5" headers.

it dosn't feel as quick as i think it should. i have an 80 trans am with a mild 455 and it ran a 8.9 in the 1/8 with street tires and the same 600cfm carb. i've been told this 350 should run in the 12s in the 1/4 which is about a low 8 in the 1/8. right now it dosn't even feel as fast. i have 3.23 gears in my camaro(3.42 in TA) and it will only spin in 1st if i punch it going maybe 10mph or less. the TA with the exact same tires(old 225/70-15s) but a posi rear would blow them off in all of 1st no matter what and most of 2nd.

here is a list of the things i think it could be:

stock fuel pump
exhaust(1.5" headers and 2 into 2.5" y-pipe(stock design)
carb misadjusted
timing off(tab on cover dosn't line up with the damper)
something weak in the ignition (stock HEI and stock type wires)

any ideas? i'm not out of my mind that this should be quicker am i?

BTW, i'm running autolite 605s at a .040 gap.

Thanks.

 

get a piston stop and find true TDC and mark the balancer properly for Top dead Center.

Set the ignition timing (with a advance timing light) at 36degreees BTDC at high rpm (4000+rpm) {maxed out advance} with the vacuum advance disconnected.
idle timing should be 12deg +... then reconnect the vacuum advance.
You should be using a 2800stall and 4.10's with that cam.

That cam should be installed "advanced' in the motor by 4 degrees eg 102 intake Cl 110ex Cl 106LSA

You may have to "degree it in". (verify and adjust installed cam position in the motor) are both the timing gears a "matched set"? makes a difference. If you only replaced the worn out top cam gear without the matching crank gear you will get trouble.

As long as the stock HEI is in good working condition its ok.
But the timing curve can be dialed in .. ( more initial at idle with 36deg at high rpm mechanical advance.) will improve idle and throttle response.
A MSD HEI coil is a nice upgrade when you get the chance.
There is a matching replacement MSD hi perf ignition module that goes with it too.

the exhaust is way too small. you need double the pipe on the Y pipe.

2.5" pipes off the headers merging into a 3" to 3.5" merge collector ( flowmaster #Y250350)
minimum 3" exhaust pipe 3.5 is better. Big muffler behind the axle. You have to custom build this .
The headers are a little too small but the exhaust Y pipe is the main problem. 1-5/8" shortys or long tubes would be better.
Typical flat tops replacement pistons {H345p) are .045"+ down in the bore. Your actual compression ratio can be as low as 9.1:1.
A big difference from 10:1. did you measure the head gasket thickness? some are .045"+ in the kits.

replace it with thin .015" head gaskets to get the actual cr closer to 10:1

The fact that the timing pointer is not lining up is a good clue to me that the motor is not "built to spec"

it's all in the details.

 

i put a brand new timing set in and lined the marks up. its a cloyes "true roller" or something.

how big of a difference do you think i'l see if i change to a set of hooker 2055s that come with the 3" y-pipe?

also, i know i need a steeper rear end but it seams like it has a ton of low end torque but it dosn't want to pick up like my TA picks up at about 3000rpms. off idle it will spin at about 1/2 throttle. it realy feels like something is holding it back if you know what i mean. it feels like its got a little more on the bottom than my TA with a 455, my buddy even said it feels like its got more on the bottom.

 

your exhaust is holding you back a lot. The timing being off would give you the same symptoms, and you need that fixed ASAP!

You also need the Hooker 2055's, or the SLP 1 3/4's. Then in the time slip that you want to be in, you could go either 3 inch catback, or a 4 inch catback (only Mufflex makes this I think).

The ignition isnt really holding you back too bad, but I'd be upgrading that so you can run a bigger spark gap.

 

Nothing to be gained here. Big spark gaps are for firing a emissions engine ( lean air fuel ratios) with lots of egr etc.. Just shortens the life of the cap and rotor a .035" gap is about the best overall.

 

"it realy feels like something is holding it back if you know what i mean."

The Y pipe has a lot to do with this..

On a two into one exhaust system with shorty headers and a Y pipe the Y pipe design is critical.

Unfortunatly you cannot buy a good off the shelf Y pipe for Fbodys,, you have to buy the parts and weld up your own.

But its worth it in the end. Start with the flowmaster Ypipe and mandrel bends and weld up your own exhaust.

Uncap the exhaust at the headers and take the car for a ride. Then you'll see how much the little exhaust system is killing the power.

 

Wear a set of headphones, so the noise doesn't re-calibrate your butt dyno, as it always does with inexperienced owners.

 

where is a good place to get mandrel bends?

 

Most good exhaust shops can mandrel bend pipes for you.

 

oh, you must live in a area that has places other than midas

 

i think i'l just go with the hooker 2055s, there supposed to have a pretty good y-pipe. the only thing is the AIR tubes. anyone have any idea on what to do with them?

 

Cutting them off with a hacksaw sounds like a good idea to me, then weld, or have someone weld the holes shut. Or, if you don't want to screw with all that and then pay the additional $'s (coating) to keep them from rusting away into nothing, you could get the stainless slp's without a.i.r.

 

You can lead a horse to water but you can't make 'em drink.

Check out Traxion's car to see what needs to be done fr a true highperformance exhaust system on a Fbody. it's not a bolt on but worth it in the end.
( The "Mufflex Y pipe" is Flowmaster pn#Y250350)

You could substitute hedman #68460 1-5/8" long tube headers for the hookers to save some $$$

Gotta take that cork out of your vortec engine if you expect it to perform.