The L81 Dragon is Breathing fire!

[tazdevl35]

After 14 monthes and a lot of time and money, I got her running today! Even with stale gas the power is obvious. 30 minute cam breakin at 2000 rpm and a few carb adjustments along with a few repaired vacuum leaks and she's breathing serious fire. In gear, light power break it shreads the tires and barks out the exhaust. Even the valve adjust was perfect first time. UNREAL POWER! Tomorrow I will drive it and see if there are any carb tweaks that will need to be made. I set timing at 10 degrees before tdc and the the total advance is 36 degrees. All the computer stuff works perfect and there was NO check engine light. It never came on once. After tune in and one more emissions check next month, it will be eligable for antique tags. Then I will put on the Super comp Chrome headers and side pipes. It should sound kick butt.Question is where can I put the O2 sensor when I put the headers on? I have a NOS 125 power shot plate setup to put on it after the headers and pipes go on it. The I will be going after the C6's and the big block cars too! Oh by the way, even with the computer distributor and carb, in spite of 268h comp cams, the idle is fantastic at all times(start up hot soak and restart hot and cold idle etc.) Steady and strong! And It idles at 700 In drive to boot. L81's kick ass...no doubt.


Now, Its beer thirty!


Taz :booty

 

[Barry08]

Taz,
Bring us up to speed on your project?
What did you do to it?

Barry

 

[gedmeyer]

This is encouraging news for me. I'm a little nervous about computer problems I might encounter after my 383 rebuild is back together!

 

[tazdevl35]

The stock L 81 was removed at 54000 miles with massive oil leaks and wiped cam(common for late 70's- early 80's small blocks) and torn down. I dissassembled the block down to bare and had it hot tanked and magnafluxed. Crank was polished and checked along with the line boring being performed. GM pink rods installed with flat top pistons fly cut for clearance. Rolling assembly balanced. New bearings and freeze plugs installed. Block was decked as well.Childs and albert rings,Clevite bearings and brass freeze plugs used in rebuild. Block painted and baked Chevrolet factory blue.Comp Cams 268H cam installed along with Pete jackson Gear drive under modified(slightly) timing cover.Trick Flow Specialties Gen 1 heads on top port matched to the Edelbrock Performer EGR intake.Chromemolly pushrods and Harland Sharp full roller rockers on top, 1.6 ratio.Chevrolet tall valve covers had to be used for valvetrain clearance, the stock magnesium L81 covers wouldnt fit.Also a high volume oil pump was used in the short black along with a windage tray and modified Small block oil pan for clearance. All emissions equipment except air pump reinstalled including the feedback carb and the computer controlled distributor. Accel module and BruteThunder coil along with Accel Blue custom fit wires.I have a NOS 125 power shot to go on after break in and emissions inspection( the last one I will ever have to do) and beyond that the Hooker Super Comps and Sidepipes will go on. After this year the car will be an antique. Also, I used a 800rpm higher stall converter (for lockup trans) to offset the cam.This was cheap, 125.00 from a trans shop instead of 600.00 from one of the Trans guys(B&M etc)I will see how the performance and driveability are with the stock gear ratio and if I'm not satisfied I'm going to go with either 3.55 or 3.73 . Well I'm off to get some breakfast and out to dial in and finish up my L81.


Good Cruising

Taz :dance

 

[Rowdy1]

Sounds GREAT!

Nothing better than a plan coming together, especially the heart of the beast, the ENGINE!!
I have a question and as you progress I'd be VERY interested to see how you make out finding headers to fit the Trick Flow heads. I've done extensive research and talked to Hedmann, Trick Flow, you name it, NO ONE makes full length tuned headers for my small block in a 62 BECAUSE of the angle of the spark plugs in my heads. I'm going to have to get a set, I know which ones, mark them for spark plug clearance, send them back to Hedmann for adjustments, then have them coated and install. A much costlier way to go because of multiple shipping as opposed to buying direct and bolting them on. Please let me know how you make out.

Thanks
Lou

 

[GerryLP]

Taz,

I am gald to hear about how well your project is going. That CompCam 268 really is a nice cam, and with the 1.6 rockers, you shurely getting the most out of its lift.

What was the compression ratio you ended with?

 

[tazdevl35]

10.75 to one is what we ended up with if the machinists math is correct. I drove this thing home last night and all I can say is wow. According to the cam card its a 1500-5000 rpm cam.I can say after 100 miles of breaking in I wound her up one time at WOT. Manualy shifted at 6000 hit second and the car went sideways. And yes in case you were wondering it was still pulling strong. After that it was back to breaking her in gently. The car has great manners too. Driveability is way better that it ever was before, although gas mileage may have suffered. I dont know though , I had a full tank of year and a half old gas I had to burn off. Sunoco was closed yesterday so this morning I will be filling her up with 94 octane . I'm sure she'll run much better on that than the stale crap in the tank. Also, i will be needing new tires soon as it lights the crap out of them even with the stock gear ratio. But it does need exhaust, I can hear it "whooshing" out the back under harder acceleration as it winds up. I was going to put super comps on it and still will, but until It becomes an Antique I ordered mid americas dual stainless 409 exhaust for 81's last night.Then this spring when I take it thru its last emissions test I will put the super comps and sidepipes on it. Meantime the NOS can sit in the closet , I'm going to enjoy driving this thing for a while.



Taz

 

[gedmeyer]

What'd you think about those stock gears? When my stroker is back in the car, I'll be running those stock 2.8x's. I'm curious to see what that'll do. I've got a 1500-5800rpm comp cams magnum series in my beast too.

 

[tazdevl35]

Stock gears are not bad.I get a 85 mph cruise at 3000 rpm which isnt bad at all.Its very good out of the hole too, considering the ratio. The stall converter helps out on that I'm sure The one I have in there now locks up solid at 2000 rpm's.If you hammer the throttle up past that on launch, hold on, your gonna get a neck snap for sure. It has a tendency to roast the tires if you go past 1/2 throttle on takeoff and forget flooring it. Even with the 2.xx rear it spins the dog doo out of them. I replaced my 14 year old BFG T/A's yesterday with Dunlop GT Qualifiers-255 60-15. Very nice ride indeed smooth and quiet not as harsh as before. My buddie owns a tire shop I got them for 290.00 including mounting ,balancing and disposal of the old tires and tax too. I was real happy with that! Now, if my exhaust would just show up so I can go get that installed I would be truely happy. Keep in mind all the performance I have right now is thru a totally stock exhaust. Can you imagine what it will be like with true duals on it? Awesome! Again, all I can say is if you are considering doing a L81 computer car dont be afraid of the computer system. Done right, it will run very well and have great manners too!




Good Cruising!


Taz

 

[gedmeyer]

Yeah, I've been planning on working with the computer system too. When I get my stroker in, I'll be running stock exhaust as well. I will switch that out as funds permit. I'm running a 4 spd manual. Would you suspect any differences because of this?

 

[Dave L.]

Thanks for the info. I'd like to keep my computer/carb/dist when i up grade my motor down the road.