Recipe for breaking 12s with a 355

[stomis]

My car has run a best of 12.9 @ 108mph. And it's good for low 13s on most days. In my signature are the build specs, and you'll notice it's a very "old fashioned" approach to getting good power... big solid cam, lots of compression, and a big stall on a low geared trans.

from lots and lots of reading and research, here's the combos that I found hit consistant 12s on a 355motor.

Obviously, a big cam helps. My solid cam with 0.495lift and 0.236dur was pretty radical a few years ago, but cam technology has exploded since then, and you can now find upwards of 0.530 lift on a streetable application. You'll always make more power with a solid over a hydraulic. But they wear quicker and it's a headache to lash and adjust every so often. But that's old school anyways, and I highly recommend you check out a roller valvetrain option.

Heads are HUGE! my engine was built on a budget, so the 54cc chambers on the L98 heads was a good option. But these heads don't flow great, even with port work. Edelbrock delivers awesome performance with their RPM heads. You can get them with 58cc chambers, very small port angles, and great flow numbers. Check it out...

When you're chosing pistons, make sure you do you math on compression ratios. Make sure they work well with your heads, and make you can run pump gas. Generally, 10:1 compression is comfy with today's low octane gas... 10.5:1 starts to push it.

To run a big duration cam and keep the car streetable, you simply cannot use anything lower than a 2800-3000rpm stall. It'll be a pig on the road and your brakes will just suck. Talk to the guys you are getting the cam from, they'll usually recommend what stall to run.

And keep your 3.73 rear gears. My 3.42s are great for the road, but only pull 5200rpm thru the traps... which is not in the powerband of my cam. Your 3.73s will pull you thru the traps with a good strong rpm.

Beyond this, it comes down to basics... Don't cheapout on the driveline. Make sure you buy quality low friction parts. Less friction in your rotating assembly means more power.

Experiment with weight reduction and transfer some load to the rear of your car. Suspension is another key element. Choose a tire size that works well... bigger is not always better. Beef up the rear springs, install a rear sway bar, and box your rear control arms. And when you're dragging, pulling off your front swaybar helps transfer weight to the rear at launch.

Anyways, I'm sure alot of this your know yourself... but for more tips, there's lots of smart guys on here that will help you out.

Thanks man that was very well written and I pulled out plenty of good little tidbits I either didnt know or forgot.

The roller cam is one of the things I'm going to looking into. I know it can offer me much higher lift with lower duration. The other thing I considered to save a couple bucks and get the same affect was using 1.6 roller rockers.

We'll see what this next week brings. If I get this set of 906 vortecs for $150 then I'm gonna blend em a little and run em. Where ever that gets me it gets me because you cant really beat the 400hp range for $150.

 

[larryo454]

Hi big duration cam are fun to run on the street as long as your not doing the 100km runs or more. LOL i get 3mpg out of my bbc on the street but u pass everthing but the gas bar 😀 I like when i can go the road at 100km and jump on it and break traction on the tires if you want. But i think u can have a good starting point with 10.5 compression and a good cam like people are telling u. the caomp cam 305H cam is good for the street i had a 355 with this cambo it worked good in the chev stang

 

[stomis]

Hi big duration cam are fun to run on the street as long as your not doing the 100km runs or more. LOL i get 3mpg out of my bbc on the street but u pass everthing but the gas bar 😀 I like when i can go the road at 100km and jump on it and break traction on the tires if you want. But i think u can have a good starting point with 10.5 compression and a good cam like people are telling u. the caomp cam 305H cam is good for the street i had a 355 with this cambo it worked good in the chev stang

Well I'm definitely not looking for a 5mpg pig. Im expecting 10-15.

As far as a cam I think I'm gonna use the lunati 60103lk from summit with 1.6 roller rockers for some more lift.

 

[Doober]

You can do it with Vortecs... I have faith. A good roller cam, just a little bigger than the GM hot cam and you'll have a driver that will make great power (hot cam is rated idle-5,000 or 5,500). Keep the LSA up and you should be ok on vacuum. You'll definitely need to upgrade the springs to accommodate the lift, and either tap for screw-in studs, or pin the pressed in studs (imo). Compression is also your friend.
http://www.summitracing.com/parts/CRN-119701/

 

[stomis]

You can do it with Vortecs... I have faith. A good roller cam, just a little bigger than the GM hot cam and you'll have a driver that will make great power (hot cam is rated idle-5,000 or 5,500). Keep the LSA up and you should be ok on vacuum. You'll definitely need to upgrade the springs to accommodate the lift, and either tap for screw-in studs, or pin the pressed in studs (imo). Compression is also your friend.
http://www.summitracing.com/parts/CRN-119701/

O yeah forgot to mention the vortecs are already done up with 2.02s, screw in studs, and bigger springs 😀 And not beehives, its actually cut for bigger springs proper like 🙂

I am going to give the roller cam alot of thought. I know the motor will be WAY more streetable with a roller cam.

 

[custom442]

seems to me you could look at weight savings. hood and trunk lid alone can shave you near 100lbs if you don't mind hood and trunk pins, plus 2 lightweight bucket seats vs. stockers is another 80lbs. throw out heater/ac box and crap you don't need in the engine bay, I've found there has to be at least 40lbs of bolts in these damn cars. If your track allows it you can get exhaust cut-outs welded in and shave another .1 or .2 off the ET

 

[stomis]

Yeah I'll get rid of the typical stuff. Its gonna be a DD so HVAC stays. I do plan on getting a w30 glass hood. Maybe I'll look into the deck lid also.

Aluminum intake should shave 40 lbs too

 

[custom442]

Yeah I'll get rid of the typical stuff. Its gonna be a DD so HVAC stays. I do plan on getting a w30 glass hood. Maybe I'll look into the deck lid also.

Aluminum intake should shave 40 lbs too

the w30 hoods are heavier they're more for looks. Check out vfn's lift off ones I think they have a 2" cowl hood or stock style that weighs next to nothing (cheaper than the w30 or bolt on style and half the weight)

mmm aluminum intake, if you're taking it apart maybe you can score some cheap hypereutectic pistons. The heads are limiting the most though, not just in upper rpm that you need for the 1/4 but weight. All this money being spent on the whole car could be spent on a pair of used AFR 195's or fully ported trick flows/world products/patriots and it'd get you under 13 in a hurry with the right cam

 

[stomis]

Yeah I'll get rid of the typical stuff. Its gonna be a DD so HVAC stays. I do plan on getting a w30 glass hood. Maybe I'll look into the deck lid also.

Aluminum intake should shave 40 lbs too

the w30 hoods are heavier they're more for looks. Check out vfn's lift off ones I think they have a 2" cowl hood or stock style that weighs next to nothing (cheaper than the w30 or bolt on style and half the weight)

mmm aluminum intake, if you're taking it apart maybe you can score some cheap hypereutectic pistons. The heads are limiting the most though, not just in upper rpm that you need for the 1/4 but weight. All this money being spent on the whole car could be spent on a pair of used AFR 195's or fully ported trick flows/world products/patriots and it'd get you under 13 in a hurry with the right cam

Some serious aluminums are in the future when I get a 406 in it. For now the vortecs are gonna stay. My aluminum intake just came in the mail actually 😀

 

[khan0165]

I went thru my post again and I noticed I drifted off topic a little...
I mentioned that my build is very "old school", as in it's a simple way to get power from back when not many parts were available.

If you've done some reading, you'll notice that engine building today (compaired to back a few years ago) is all about efficiency now, rather than blunt force and bigger parts.

You can free up lots of HP from simply running better parts.

Getting some H-beam connecting rods, and better pins & pistons will help you rev quicker and higher. A roller cam, will free up some friction in the valve train. Valve springs are another area where people over-indulge and get springs that are too stiff, so look out for that. Port work also works, but if you're like me, and you're not too handy, even a gasketmatch port job will go a long way. Take a shot at polishing your ports and chambers. Running an electric water pump and a more efficient streering pump will take a load off your rotating assembly. You can beef up your ignition too with an HEI system, better wires, and maybe even a programable timing box (check out some MSD systems).

Good induction also frees up some ponies. Run a simple cold air system, even with some plastic ducting hose clamped to an old fashioned snorkel aircleaner. And if you're not worried about hood clearance, run a highrise-airgap-singleplane intake. You can even use a carb spacer if you're running a cowl or a tall hood.

anyways... that's what I wanted to add to my post... money permitting, take a look at what you can do, and look at ways to improve efficiency, rather than cramming in bigger parts.