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Difference between HB GT and Magnum Axle

PostPosted: Wed Mar 27, 2024 7:00 pm
by OUL 735 L
Good Evening all

Does anyone know the difference in ratios for a HB GT rear axle and a Magnum Rear axle.

i.e. would the speedo read the same with both axles.

Any help gratefully received.

Ian

Re: Difference between HB GT and Magnum Axle

PostPosted: Fri Apr 05, 2024 7:46 am
by StefanM
Most likely the same if talking about a 2279 axle.
Long pinion GT axle is 3.90 however. Short pinion 3.45

Re: Difference between HB GT and Magnum Axle

PostPosted: Fri Apr 05, 2024 7:56 am
by Fred Dukes
Magnum/Viva OHC 1800 axle is 3.75 marked K - 2300 axle makes D

Re: Difference between HB GT and Magnum Axle

PostPosted: Mon Apr 08, 2024 9:41 am
by GTpete
I fitted a Firenza 2.0 axle to my Mk1 GT, some years ago, but can't remember which prop (single) I used?

Re: Difference between HB GT and Magnum Axle

PostPosted: Tue Apr 09, 2024 3:05 pm
by OUL 735 L
Good Afternoon

Thank you for all the information regarding rear axles.

I am at the moment waiting for a quote to recalibrate my Twin dial dash Speedometer from a 1256 axle to a 2.3 magnum axle.

I purchased the HB GT speedo that was on ebay as that is the same speedo and will try it when the weather gets a bit warmer, will still be out but hopefully a bit more accurate

I don't think 2.3 magnums were done with a 2 dial dash, (only the 1800s were) but correct me if I am wrong and would be very interested in purchasing the speedo from one if someone has one stashed away

Ian

Re: Difference between HB GT and Magnum Axle

PostPosted: Tue Apr 09, 2024 5:59 pm
by droopsnoot
I don't believe the 2.3 Magnum ever had a twin-dial dash, either.

Might it be easier to find a different speedometer drive gear than have the speedometer calibrated? I don't know if there is one for the OHC gearbox that would match the ratio that the OHV speedo is expecting, and it's not easy finding a decent one to start with. Perhaps something to think about when you've received the quotation to re-calibrate.