3.55 or 3.91

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HemiTM

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Need a little help. I am getting ready to put together my 8.75. It will be connected to a mildly built 318 and reverse valve 904. It will be seeing the track more than it will be cruising the blvd. Should I go with the 3.55 or the 3.91?

Thanks
 
i would think with a 318, i would go with the 3:55, even if you drive it once in a while on the street. i have a 340 and have 3:55 cause it will be on the street everyday, but 3:91 may have that 318 screaming.
 
I'd go with the 3.91s because the little 318 is an engine that can rev. Also because you plan on racing it more than cruising in it.
 
I run 275-60's and a four speed with 3.91's. It's fun, but I would rather have 3.55's. The rpm's get annoying on longer trips.
For the track, the 3.91's would be better.
 
3.91's if primarily on the track. Like MtNemo said, 3000 rpm's at cruise speed gets old.
 
In a 8 3/4 get both. One for track (3.91) and one for street (3.55).
 
Yeah 3:91's. You can still drive them around town no problem. Thats a 27 inch tall tire also. Try 25.5 inch tall tire with 4:56 gears....
 
3.91 and an extra set ot 235 75 15s for the rear if you gotta road trip it. easier to change tires than gears. 318 likes low gears as well as any other small block. SS, 3.23,be real. never been a race gear unless you got gobs of torque.
 
3.55's or maybe 3.73's?

I'm thinking 3.91's would be sweet but yeah the RPM's will annoy the hell out of your road trips specially when some idiot in a supra wants to race at highway speeds.LOL.
 
How about 4.30's? My bracket 318 which I drove to the strip struggled even with 4.30's. 60' times were in the 1.90's. Don't take me wrong, I love that 318, it just needs all the help you can give it on the low end. If you are going to race the car, consider 4.88's. Seriously.
 
3.91 and an extra set ot 235 75 15s for the rear if you gotta road trip it. easier to change tires than gears. 318 likes low gears as well as any other small block. SS, 3.23,be real. never been a race gear unless you got gobs of torque.

I guess if all you've ever built are engines that can't pull a greasy string outta a cat's *** then that's true.
 
I would go with 3.91 for a mostly track car. Had them in a Dart with a mild 318 build before. Good for stoplight to stoplight or at the track, any thing more then a little street driving tends to get old in a hurry. Good gear for a shorter tire but I always felt for street use I should have an overdrive with them. Stroker isn't that far off. I changed to 3.23 and lost 4 tenths but MPG went from around 10 to almost 17 and I could drive my car anywhere then.
 
3.91s are great for occasional blvd pounding. I had a coronet with 3.91s and it was a great in town cruiser / weekend strip car. You will be spinning 3500 - 4k at 75mph right? Thats tolerable for occasional cruise and smoking some Mercedes from light to light. I only got tired of the rpms on the freeway.
 
The 318 is a high rpm screamer so I'd go with at least 3.91's if not lower since you said it's mostly for racing. If it were for the street I'd say 3.55's.
 
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