small block for FIA

[dlampe]

Ted, I also have an FIA "289" car. Check out my gallery. I would be happy to discuss some of the pro's and con's of the small blocks for the FIA. If I can help just give me a call. 618 322 6046. I will be around all weekend. I have had 2 427 cars before this and I will never go back! I love the FIA look.

Good choice!

[Dwight]

jarendall
What size tires do you have? When we check ours buddies speedo with a GPS we found they were off by 12 to 19 mph. Most guys change the rear gears but not the speedo gear or they install the wrong one. Our Cobras are set up about the same and I sure I have smaller tires, 25 1/4". My speedometer is off by 1 mile per hour at 70 mph. I have to be close because I drive 7 or 8 over the speed limit and do not want to donate some of my car part money to the "officers". But I have been stopped 5 times, but no tickets yet. I've got this thing about spinning tires.

Dwight

I guessed at your tire size 295/50-15

Second Strike Gearing Calculator



Speed (MPH) in Gears at RPM



Trans Ratio 3.27 1.98 1.34 1.00 0.68

Overall Ratio 10.69 6.47 4.38 3.27 2.22

Split 1.65 1.48 1.34 1.47


Gear 1st 2nd 3rd 4th 5th 6th
1500 11 18 26 35 52
2000 14 24 35 47 69
2500 18 30 44 58 86
3000 21 35 52 70 103
3500 25 41 61 82 120
4000 29 47 70 93 137
4500 32 53 78 105 155
5000 36 59 87 117 172
5500 39 65 96 129 189
6000 43 71 105 140 206
6500 46 77 113 152 223
7000 50 83 122 164 241

http://www.secondstrike.com/Technical/GearCalc.asp

[turnpike boy]

Dwight, his speedo is probably off some; seems most are.

Anyway, look at it this way - a 295/50x15 tire is 26.62" in diameter (www.rogerkrausracing.com/tiredem.html), which works out thus: 26.62" x 3.14 divided by 12"/ft = 6.96'/revolution

Now....1.34 (3rd.gear) x 3.27 rear = 4.38 drive ratio in 3rd. gear; 6500 rpm divided by 4.38 = 1484 revs/minute, divided by 60 seconds = 24.73 revs/second.

So. 24.73 x 6.96' = 172.1'/sec, x 0.6818 = 117.3 mph, not too far off that SecondStrike calculator.

But - go to a 275/60x15 tire, which is 28" in dia (actually, 27.9" - I cheated and rounded up), and 7.32'/revolution, and your final calculation here winds up being 123 mph - which is admittedly a ways from 130 mph, but who's looking at that speed anyway?

Hey, Jarendall, when you find a decent stretch of road....................ah, never mind.