Gear Ratios

[Bill D]

As I continue to formulate my plans to build a Unique car, I would like to know what gear ratios are available in the Jag IRS.

Thanks
Bill D

[brfutbrian]

bill, thats kind of a trick question. im not an expert but here goes. depends if the case is an early or later model case. on an early model its 3.31, 3.54, or 3.73. with a carrier change 3.92, 4.10 or 4.56. on a later case 2.88 or 3.31 only. (theres probably a ratio between 3.05?) unique`s deluxe pallet kit specs 3.31 or 3.54 . ( they have a couple 3.73s kicking around the shop too i hear). right now my cars apart in the garage swapping a 3.31 center to a 3.73. later, brian

[Bill D]

I see! I ask because I want to be as original as I can and plan to use a close ratio Toploader. I'm still vacillating between a 289FIA and a 427 S/C.

Thanks for the quick and detailed reply

[brfutbrian]

bill, if memory serves me correct the original cars had all 289 and the 427 street were 3.31 and 427 s/c were 3.54. couldnt find my liturature to confirm it though but i think ive got it right. later, brian.

[eliminator]

If have built both the 289 FIA and the 427 S/C cars with the period correct engines and transmissions. For me the 289 car gets the 3:54 gear with a close ratio toploader. The 427 S/C with the FE engine gets a 3:54 gear and a close ratio toploader, (optional is the 3:73 gear) with the close ratio toploader. My 427 side-oiler is a solid lifter single 4 (780 CFM) engine with the Blue Thunder Medium Rise intake and a complete billet valve train and a steel crank, forged pistons, ect. Approximately 505 HP, started out with a 3:31 gear, ran it 4 years and didn't like it, since I wanted a change I went to a 3:73 gear, the engine loves it and I do too. Thats my 2 cents worth.