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Discussion Starter · #1 · (Edited)
First post so thanks in advance. Finishing up sons, SG nova need 1/8 gear ratio help. Gonna have bte 8 inch conv built once I know gear. Like to cross stripe at 6800-7200 rpm , I’ve read soooo many posts , used all the calculators, but none seem to pinpoint our small ci combo. 70 Nova , 2500 lb w driver, 450 hp 355 “beginner” motor, 1.80 gear glide w brake, 9 inch , 14x32.5 on 4 link w anti roll. Car was 582 bbc w 4.30 gear 1/4 but we only have 1/8 tracks surrounding us “ N east Arkansas area . Gear calculators have me in the 6.00 & up range but with my weight & small “buzz saw” engine I’m thinking 5.43-5.67s , I’m lost in between calculations & real life experience hoping you guys can help .
 

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First post so thanks in advance. Finishing up sons, SG nova need 1/8 gear ratio help. Gonna have bye 8 inch conv built once I know gear. Like to cross stripe at 6800-7200 rpm , I’ve read soooo many posts , used all the calculators, but none seem to pinpoint our small ci combo. 70 Nova , 2500 lb w driver, 450 hp 355 “beginner” motor, 1.80 gear glide w brake, 9 inch , 14x32.5 on 4 link w anti roll. Car was 582 bbc w 4.30 gear 1/4 but we only have 1/8 tracks surrounding us “ N east Arkansas area . Gear calculators have me in the 6.00 & up range but with my weight & small “buzz saw” engine I’m thinking 5.38-5.67s , I’m lost in between calculations & real life experience hoping you guys can help .
If you want to ET well, go with the lowest gear possible.
 

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Agree with Randy. Suggest looking for a used set. 5.86 or 6.00. The first set in any of my cars over the years was rarely what I ended up running over time.
 

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I’d put 5.14s in it with a 6200 converter and change up the tires to 31-10.5s you don’t need that much tire on it ,that’s old school, I have same tires on mine and I’m in the 7s in 1/4 at 2445 lbs
 

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Discussion Starter · #6 ·
I’d put 5.14s in it with a 6200 converter and change up the tires to 31-10.5s you don’t need that much tire on it ,that’s old school, I have same tires on mine and I’m in the 7s in 1/4 at 2445 lbs
Great suggestion, my goal is to get son use to the ropes on car this upcoming year & use this little motor & ease back into the bbc platform, Cars got a new pair slicks on it & was hoping to find a one year of racing balance thru gearing / converter to get 355 down track using a targeted first gear start ratio for the 3.50 stroke crank & cross 1/8 stripe around 7000. Calculated a recommended 10.25 start ratio for the 3.50 stroke & the glide has a 1.80 low which I hope to balance between the little 355 & the next engines start ratios. Hope to have a few 3rd members set up for final combo before it’s to that point . Currently a 3.50 stroke x 5.67 gear start ratio = 10.206 & that is target for recommended ratio & a hold up is the unknown mph , having not run it yet is big factor making it tough on me to guesstimate rpm at finish. Gut feeling was to gear down 1 step numerically under this ratio & let it pull through middle of cams 3300-7400 operating range in high gear . I sincerely appreciate feedback & know less contact patch & the reduced diameter makes best sense . It’s these huge new 14.5 x 32s rollout / diameter I’m not use to calculating but am quickly learning . Yours being 2445 lbs , helps me compare even with tire dia difference, I was wondering do crossing the 1/4 at the edge of desired rpm with the 5.14s or just under ? Feel getting close to what I need to know . Thank you
 

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I found with to much gear, most motors can’t keep up with it unless your talking a comp or pro stock motor and off the line is to violent to be anywhere consistent
 

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Discussion Starter · #8 ·
I’m starting to ponder the idea that maybe I shouldn’t be as concerned with final trap rpm as I should the starting line ratio & if SLR is where it’s happy then what rpm it’ll cross at is the stripe at is the least issue between the two. I’m trying to gear it for the finish when maybe wiser to focusing on the beginning. Wondering if you guys cars SLR is slightly below or close recommend the number based on this chart I’d seen on here…… Handwriting Font Pattern Calendar Parallel
 

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Discussion Starter · #10 ·
The wider tires will be far more stable then the skinny ones. You could reduce the height, and go to a taller gear then the 6.0. But it definitely needs geared down. In my opinion.
Appreciate the reply , I’m familiar with 5.67 & 6.0 gear in my past life “dirt open wheels” 2250 lb , on G60x15 tires. Choosing to go the learn to “crawl before you walk” approach. I’m gonna try to settle on 5.67 - 6.0 ratio the as a baseline. Few more math calculations to put with all the great advice . Thank you all very much .
 

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How does the rpm drop on the shift agree with your cam? You should be able to calculate that out.
 

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I think you're on the right track with the SLR. Last thing you want is the little motor struggling along not accelerating and just riding the convertor in low gear. Right convertor and gear is everything. May wind up forgetting about that big block.
Few things more satisfing than watching your kids go rounds.
 
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