New Cam, coil, wires, plugs, traction. Why no 1/8 improvement?

Thanks for all the help and suggestions. I think the idea of a lower geared rearend with limited slip, and then two sets of tires, tall for the road, and short for track is a great idea. Can throw them in the trunk at and swap out when I get there. Never thought of that. My new tires on the rear are at least two inches taller, adding a whole lot of diameter, and taking much from my already low gearing. I assume that is where I lost my speed and time.

I usually use my tach to watch for slippage and peeling out. With my stock tires 195/75, I would watch the tach and if it started going up too quickly, I knew the tires (tire) broke loose, and would back off and slowly gun it some more. I got to where I had a good feel for how much to punch before it would break loose.

Now with the 245/60, They only break loose a bit before grabbing, maybe the first two seconds, but I did not see the jump on the tach as before, and my wife cannot see the tires from the stands, also, it could be the tire on the other side of the car from her breaking loose (most likely, the passenger side typically is the one the breaks, i guess that side is lighter with no passenger weight).

Lots of good ideas. I will try for heads and headers, at least headers, before the summer is over.

 

stock cam is 266 @ .368 lift intake, 244 @ .38 lift exhaust @ .006. Something like 198/189 @ .050.

I can give better numbers when I get the chance to verify .050 numbers.

 

Check jetting and secondary vacuum spring. If your holley 600 is out of the box - it is likely set up for a chevy 350. With the cam you are running probably need jets around 60 or 62. Most holley 600's come with 66's. Also, go to a lighter secondary vacuum spring to get the 4 barrel kicked in quicker. You probably arent into it until well after the 60 ft mark with a stock secondary spring.

Just shooting in the dark here to give you some ideas.

Cleaver

 

Ok, looks like all the bases have been covered by everyone else, like weather conditions, driver being consistent, all the other tips. But, you never said where your timing is (or I didn't see) And I don't mean at idle, I mean when it quits advancing, like around 3,000 rpm. Total should be around 38 degrees, as long as it will still crank without trying to kick back, you may need to recurve the distributor. Even with those gears, you should be able to get some 9's out of it. My little brother's Mav was stock, high 10's, then with a 4bbl, low 10's, then with headers, 9.10....We kept running it before each change to know how it went. Then, 351w (very mild) 8.20, and a 125 shot of nitrous, 7.15. Texas is pretty big, I don't know where you are, but it sure would be fun to help out.

 

Timing is up around 40 somewhere, I can't tell for sure because my marks don't go that high, and I had to estimate and make new marks with White Out. I am in Angleton, down near Lake Jackson and Galveston. Just above sea level, but the air is thick and humid. I am not sure how humidity affects the burn of fuel.

From the help I have gotten here, I am looking for 3.80 gears, heads, headers, and I think that will allow my current setup to work to it's potential.

I will go with higher compression pistons, but I want to get this thing burning oil before I tear it down. I just cannot justify tearing apart a perfectly good motor if it still runs good. And, I am not making any money off this car, just spending it. It is a relaxing hobby to help de-stress after work. The noise and wind help me relax, and just having something productive to do that actually works when I am done.

 

Humidity GREATLY affects the performance of your car. Humidity is moisture in the air. The more moisture, the harder your engine has to work to burn the fuel. Take a match and try to light a dry newspaper, then take a match and try and light a damp paper. Same principle.

Barometric pressure matters also. The higher the pressure, the more air you can force through your engine with less effort.

I'm glad it's still a DE-stresser for you...seems to be working the other way for me LOL .

Good Luck,

Later

 

dont change the heads just YET get the gears and headers first..with the 3.80's and the setup you have you will run 9.4,s to 9.2's...my stepsons car is set up the same as yours..less the big bumpers of course

 

I have another post regarding the pros and cons of different limited slip differentials. Because I think the 3.80 rear is my next project. I want the drive working fine, so as I make improvements to the motor, I can calculate gains with significant numbers.

What about 4.11 gears and a taller tire, like 245/60r17?

I am using an online drivetrain calculator

http://www.drivetrainsuperstores.com/calculate.asp

and it is saying that that tire with a 4.11 should go 70mph at 3200 RPM. That doesn't sound too accurate, but I could easily live with that if it is true. How tall would my rear tire have to be with a 4.11 to get speeds like that? If this is not feasible, it sounds like the 3.80 is a good compromise.

 

yes, its always nice to have all the right equipment to make your car run better, but there is a lot you can do with what you have right now. timing & how it comes in, jetting, plug gaps & heat range, secondary carb tuning, starting line rpm, shift points, how full the gas tank, air in front tires, cold air box for carb, air in rear tires, ..... make only one change at a time & watch the weather gauges. yes, get them. a $10 set of temp & humid, or temp, humid & barometer, and a log book. take notes.

you say that you now have no tire spin. this is a good thing. do you want to go faster, or bracket race? if you dont really care how fast you are, tune for predictability & practice your lights. while there may be some advantages to being the faster car, its not all that one sided. just cut a light & run the number on the car. let the other guy screw up. the car with the better package wins.

if you get the gears, get some type of traction devices, ie traction bars to control wheel hop, & a posi or mini-spool to make both wheels spin equally. you will almost certainly need it. costwise, the mini-spool is cheapest (about $35), but you might not care for the way the car drives on the street. its not the horror some people think it is, but driving in the rain requires some restraint, & equal rear tire pressure is important. i forget what kind of usage you said this car sees. most any decent posi unit is going to run close to $400 new.

 

This car is 90% drive around town, slow and loud, gun it at red-lights, but not so much to peel out or speed and get a ticket. Just relax and cruise. 8% drive 40 miles highway to work, and 2% take to the track on weekends to test and tune. If I start to get decent numbers, where minor tuning will make some difference, I may bump 10 or 15% off the "drive around town" and add that to the track.

I do have those cheap bolt-on traction bars, with only an inch or so of give between the rubber and the springs. I don't get any hop when I peel out. I think it is bottomed out by that time and stays nice and smooth.

I am guessing a posi would make me happier than a spool. Unless I hear otherwise. How much "hop and noise" are we talking about around dry street corners and intersections?

 

i have normal cheap tires on the rear inflated to max load pressure. keep them equal pressure as much as possible. cheap because the tires do get a little "fuzzy" from the friction, & wear a little faster. not wide since it helps keep the chirping down. yes, you hear scuffing noise at slow speed in a tight turn & if you shift in a turn it chirps easily. you cant hit the gas hard on a turn in slick weather; it will break loose. but so will a locker. if you hit the gas hard in a turn like an on-ramp, it will try to go straight. if you drive up the ramp normally, no problem. if you accelerate to a curve and keep on the gas into the curve, it will try to go straight. if you let up, you'll go around the curve. you cant drive stupid with a spool. you can drive fairly normally with one. sharp right turns from a stop are where its most noticeable. and i have a manual steer (former power) car which makes everything worse. if you have power steering, you would notice it even less. (by the way, if you have power steering, drop the belt at the track if possible. usually worth a tenth or two.) if you get headers, they often limit your turning radius slightly since the steering arm often hits one of the tubes, so less turning radius.

its the cheapest way to go, & gives the best performance results. if you went that way & didnt like it, then you could try the high dollar route. you would lose the cost of the mini and the cost of the setup; if you lay out the cost of the traction lock & it isnt enough, then you're out a lot more money.

email me if you like, or post any more questions here. think it over.

 

I could get a spool for $20-$40 and try it out. How hard is installation? I might do it and try it, and if I don't like it, I could hold it for later or sell it.

I guess my question is, is installation difficult? I have never done any rear work, and don't know my way around it, except in theory.

Also, how difficult (to swap) and expensive are new gears in 3.80?

 

One more thing, if it still has the stock fan, you might think about going electric. The stock one is heavy, and has no clutch, you might see some good gains there. I know my Mustang is a big block, but it went from 8.20's to 7.59, by adding stuff like a good ignition, electric fan and water pump, and just some minor tuning. Next is the Glide, and a 532"

 

Fan is still stock, and I lost the shroud years ago. I have been looking for a new fan, but figured I would wait until rebuild, and go with a new fan and radiator as a unit with a larger electric fan and it's own shroud.

 

Clutch fan is about $30, well worth it.