How to sqeeze out a little more speed?

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Vortex

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Last summer I picked up a 68 barracuda. The owner knew very little about the engine build. Soo....I back tracked to the owner before him. And he didn't know much either. But betwen the two of them this is what I found out. (not to mention crawling around my car and doing a little research)
Engine is a 318 +.030 (total engine rebuild)
Cam is "a little bigger". One owner told me. lol
Edelbrock performance intake with a 750 holley on top.
340 exaust manifolds.
Stock 4-speed trany with hurst linkedge.
Stock 8 1/4 rearend with suregrip. (no clue on the gears)
Monroe air adjustable shocks in back.
Now running with BF Goodrich R245/60 R14 at 35psi.

This is my everyday driver/race setup. This weekend I happened to win in the trophy class at Firebird Raceway outside of Boise, Idaho. My best ET was 15.766. (never touched 4th gear)
My question is, what can I do to go a bit faster without digging into the engine? Such as lowering tire pressure, lbs on my shocks, type of engine oil, different spark plugs(autolite), etc......
 
This may be a little more than you want to do, but it sounds like you could use a little more gear in the back end. Also you might want to drop down to a 600 or 650 cfm carb. On the cheap end, you might want to adjust the timing, and or, change the jets in the carb until you get your best et's.

Jack
 
Well its not digging into the engine but I would crack open that pumpkin and find out what gears are back there. A gear change is usually the change that you feel the most. Try some different timming and (de)tuning on the carb. What were your 60' times? if you werent spinning and were in the 1.9-2.0 region for 60's then thats about as good as you can hope for on street tires. I like to take ten pounds of pressure out of my rear street tires at the track just for a little extra umph off the line but you take out too much and your mph starts to hurt. Other than that take your spare tire and jack out, keep the gas down to 1/4 tank and do anything else you feel comfortable with to lighten up the chasis.

Edit: Coyote beat me to it!
 
My 60' times averaged 2.401 through 4 passes. I got only a tiny bit of tire spin on 2 of my passes. My best 60' was 2.289 and the worst was 2.532.
 
Try switching all your fluids to Royal Purple, it is a little more expensive than the regular stuff but wow, what a difference it made in my car. I changed everything diff, tranny, engine, and coolant additive. Give it try, i think you'll like it.
 
u need gears to really go faster. i would say 3.90s for your set up, unless you drive it on the hwy a lot. jack the car up on one side only and do the old tried and true test for gear count:

http://www.slantsix.org/forum/viewtopic.php?t=16476&highlight=rear+end+ratio

ditto on the smaller carb...you'll go faster especially on your 60ft times, which are pretty tuff with a stick anyway.
regular shocks in the rear and address the sagging a-body rear end with a re-arch or new springs. pinion snubber if you don't have one.
play with your ignition curve a bit to get about 36* total timing all in by 2K. might vary a little depending on weight and atmospheric conditions...

sb
 
If its a daily driver,get a 600 vacumn secondary carb for it,and jack it up to see what gears are in it.Also go to 15 inch rims and tires in the rear.If you are spinning the boots now,gears are just going to make it worse,taller tires and rims,Mrmopartech
 
Thanks for all the great info. I'm sure with a little "tweaking", I'll be able to get into the high 14s. I think I'll find a pair of 15" wheels and slicks then see about getting differant gears and carb.
Speaking of gears, since I have a "suregrip" rearend, will I have to jack up the entire rearend to do the gear count?
 
Yep, both tires must leave the floor.
The ratio is stamped on the ring gear.
 
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