GSE guys, how about some Chassis advice?

I forgot to say that I have a much tighter converter that runs about right on the RPM you had figured. I have had many different converters in my car in the last few years and the MPH stays the same, they just move the RPM up or down. The track I race on almost always has a headwind so maybe the drag of going through the air acts like a govenor on the MPH. The main reason I have the loose coverter in is I had a hard time to get it to idle in gear on the street with the tight one. My cam is not the best cam for idle, its a Poston 105A with 105 lobe spread. Tom W

 

Thanks, Gary. I'll take any advice you have to offer. I've seen your car run, and you obviously know a heck of a lot more than I do about all of this.
You nailed exactly what I am trying to do with this car. I want a car capable of high 10's or very low 11's that I can baby a little and run mid 11's with consistantly and drive on the street.
I already have some good bushings and the suspension is going to get a total rebuild, including boxing the control arms.
One mistake i made already is getting my converter before I had the engine completed. ou: I had it built for a ported iron headed motor with a 308S cam. After I looked at the price difference in having a set of iron heads rebuilt compared to new aluminum heads, I decided to go aluminum with a hydraulic cam. I don't know what effect that is going to have on the combination. I might have a converter that is way too loose. In that case, I guess I will have to have it adjusted.
Anyway... I guess I will try out the stock suspension and add parts as I need them.

 

That RPM doesn't sound too high to me... actually, it sounds just right.

 

I guess, unless he's wanting to go MORE than 116mph! With 29.5 tires, he's pretty much maxed out on tire dia. without tubbing. Only other way to reduce RPM's and still go faster is to reduce gearing or reducing the amount of slippage at the top end.

 

That is one of the main reasons I want to go to 3.73s. I think there is more in the car if I can get rid of my ignition problem and I want to try some other little things but I don't want to spin the motor any higher with stock rods and the heavy sealed power forged pistons. Can any of you math guys give me an idea on how much rpm I would loose going to 3.73s over 4.10s at same MPH? Or would 3.90s be a better setup? Tom

 

Tom,

The calculation is simple IF you are not making tire changes, convertor changes,etc.

You currently run a 4.10 at 6000 rpm.

A 3.73 gear divided by a 4.10 = .909756 x 6000= 5458rpm
A 3.90 gear divided by a 4.10 = .95122 x 6000= 5700 rpm

You can also go the other way, if you want to run a 4.33 it would be;
4.33 divided by 4.10 = 1.056 x 6000 = 6336 rpm
You can do the same thing with tire circumference to see the effect that tire changes have. I'd suggest a 30 inch (94 circumference) tire or no lower than a 3.90 gear if you want to kill a few rpm's. I would guess you would slow down a little.

Tom

 

Thanks Tom, I will be on the same tires a while since I just got them end of last year and the same converter will have to do a while, don't have the cash to get a "good" one. Its a B&M 3600 10" hole shot, or super hole shot, something like that. I took off the Holley ignition box and put my stinger back on this spring to see if my poping and missing go away in high gear. The box is the only thing left I have not changed. I have not been close to that 116 MPH in a couple years because I can't get it to run clean and pull in high gear. I noticed that on every pop or miss in high gear the tach also jumps around which is telling me its ignition and not carb or valve train problem. I wish I knew someone who was going to dyno a motor, I would send them the holley ignition to see if it does the same thing for someone else. If I can get it to pull clean in high gear I am hoping for maybe high 11.30s at 116-117 MPH range this year. The 3.73s kill more RPM than I thought, looks like 3.90s or just guts it and leave the 4.10s in. the motor will go past 6000 no problem but I can't afford to have a major bang, rattle rattle in the motor this year. I am hoping to see you and the other Chicago guys this year at Byron if things work out. Tom W