Starting to collect parts for my vintage fed project what ring and pinion ratio do you run in the rear. Looking to stay under 140 with a 550hp small block not sure on a stick or glide yet.car is a vintage short wheel base style car.
Tire size has a lot to do with it too, most I know are between 3.90 to 4.11. Mine has 4.10 and a 33 tall tire.
it depends on car weight, engine size, hp and rpm trans and tire size also if your running a trans brake if running an automatic. how long is your car?
when my friend first built his 160" fed he had a 406 with vortec heads street motor he had 4.10 gears and 29x9 slicks and ran 6.40 in the 1/8 and with every upgrade to the motor the tires, gears and torque converter had to be changed now running 33x10.5, 4.86 gears and a 8" race converter and had to add wheelie bars to the car
When I spec a car and I have speced a few. I need to know the cam duration and is it roller , flat tappet solid or flat tappet hydraulic. Then I know where the power peak is. I also need to know the weight of the car. A FED will weigh 1600 to 1800 with driver and fuel depending on length and engine. IE mine to the left weighs 1704 with me aboard. (I weigh #300) I run a 28 inch tire. I can also run a 29 as my sweet spot is in between so either works the same. I gear the car for engine power peak in the lights. Then I work towards that end unchanging till I get there and I do( cause math never lies.) One of the most common things I see is a fellow switches to a rail from a door car and gears it the same. Then he walks around for several years wondering why he keeps spraying motors and not going the MPH. Here is a good example. A friend bought a rail out ofLluskville area in 1989. It was running low 10s . It had a 454 with aluminum heads but the motor was beat. He asked me to build him a mill. Since he is a shoe and not a wrench I build a motor that will need no maintainance as i will not be there. I set the RPM limit at 7000 . I had comp cams make me the flat tappet cam. I used the new GM heads then as the aluminum were totally junk, well past their good days. I checked the diff or had Vern do it as he was crewing the car. It had 456 tail in it. I speced 410s and found at set at Glen Laroques in Ottawa (57 Olds diff) Vern installed them. I finished the motor and after a couple of weks I came home one day to find a picture and a note from Paul Ruttan the cars owner. 8.85 158 MPH. The motor including a new crank and heads cost $4500 pus tax. Had we left in the big gear the car would still be running out of the 8s for sure. (Probably still tens ot high 9s)When Paul retired from Dragsters he sold the car and the motor was split from the combo. The fellow who bought it put it in a legal street roadster drag car weighing about 110 lbs less than the rail. He never saw an 8 or anything close to it and to this day has been busting motors and parts . Paul ran 6 years with Zero maintanance other than oil changes. The good motor was torn apart and improved. It never ran a full p*** again . (dang geniuses monkeying with my stuff!) He finally asked me one day . I told him you have too much gear for your motor. "I ran that in my buddys chevelle" he told me "with the same motor I have now." Well a Chevelle is not a rail . The chevelle ran in the tens . So does his roadster. "So just where did you think the extra speed would come from and the extra RPM?" I asked. He told me because the car is lighter . True, but it also requires less gear to achieve the High Speeds. The RPM doesnt come from nowhere. The HP can push the lighter car faster but just because an engine is installed in a rail doesnt change its RPM range. The cam decides that. Tires:Roughly speaking 1 inch of tire hieght is = to 1 gear ratio step. Ie 3:91 with 29 in tires = 3:73 with 28 inch tires = 4:10 with 30 inch tires. Just to give an idea. A #1700 car with a 31 inch tire , a 550 hp engine peaking at 7000 rpm with 410 gears can run a best of 8.48 in the 1/4 mile. Anything in an 8.5 range would be acceptable as 8.48 is under ideal everything which almost never occurs. Don
Thanks Don as always a wealth of information Looking at a te440 style ch***is My small block is my ex circle track motor 358 billit crank h beam rods weisco pistons flat tops, zero deck small block phase 2 bowtie headscut to 48cc combustion chambers flat tappet cam lift 530 intake 540exhaust duration 247intake 251 exhaust 107 separation angle installed 101 intake centerline. looking to run a vintage tunnel ram intake single 4. i have several trans options short three speed saginaw or the little gm tree speed shortened. dont have much experiance with automatics . Picked up a winters floater looks like a quick change only no quick change.the ring and pinino ratos available for tha rear are. 411 457 486 514 it currently has a 486 My weight is 250lbs i have several clutch options a small triple disk using a automatic ring gear or a standard aluminum flywheel set up. The motor on the dyno was around 500hp at 7500 we ran it at 7000 in the circle track car. not sure what the car will weigh this will be my first drag car.
some people like short tires i would go with 33"and the gear you already have, try it in the 1/8 to see how many rpm your turning, it all depends on your torque curve and torque converter
Yes ratio wise that is true but traditionally 33 are very wide. usually 14 or so. I run 8 or 10s . So i would suggest one make a piece of plywood 33 inch high and 8 inches wide. Drive down the road at 60MPH and hang the wood into the wind. Probably you wont be able to hold it. I make a point of running as narrow a tire and as low as I can run and still give nothing away traction wise. I figure it is always easier to save power than to make it. It is true though the math works with a 33 and the taller ratio. Don
Daily driver about 12k a year with lots of 70+ hiway in Az. 3.73 rear with 2.74/1.57/1/.67 OD ******. Still spin them but about 68 mph @ 2k rpm cruise.
Don I'm talking about 33"x !0.5" not 14" 16" or18" I don't like short wide tires.I prefer to go up not out.
i have a FED built by Foy Gilmore in the late 90s, 186"wb, ZZ4 crate motor, the only changes to the engine are cam (GM hot hydraulic roller and zoomies) it weighs 1250 plus my 180. it has a 1.76 powerglide, 4.88 gears, 33x10.5w slicks. the last 3 p***es were 5.94 @ 115 with a 1.27 60 ft, on pump gas. If i had another 150 hp, i'd probably try a 4.11 good luck you'll love it
I've got 3.70's on a spool in mine but I don't know what I'm doing. I had some 30" picrusts but sold them and just put some 29.5 MT ET's on. Curious. Is everyone running a spool or has anyone got an open differential?
powerglide, 4.56 gear, full spool, 33x12 tire, 1590 pounds wet with me, 133 1/8th and 165 1/4 at 8200 rpm 4500 stall and 700hp at the crank, sea level..... your better with taller tires due to rollout and keeping them 12 and under wide (patch width). besides anything wider looks out of place on a FED, here is a great calculator site to give general idea, http://www.wallaceracing.com/Calculators.htm
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