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Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:09 pm
by GarysMK1
Eveng gents.
Q. My 850 mini seven engine is a little underpowered. Can i replace it with a 1275 motor and still retain my new hybrid 4 syncro box and wand shift or will they not mate up ? Also, can the box take the extra horsepower ?
Regards Gary
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:13 pm
by Daz1968
Any mini gearbox will physically fit a 1275 block, only early 3 synchro cases need modifying for clearance according to gizzard book, as yours is a 4 synchro casting can’t see an issue, as you have had it rebuilt then it will be strong enough for a standard 1275, I would think fitting a 3.44 diff would help with the larger engine for cruising,
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:14 pm
by Spider
Yes. All the 4 Synch boxes will accept a 1275, you'll need to find a 1275 Primary Gear though and yes, no problem with the power.
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:30 pm
by Southwest
Daz1968 wrote: ↑Sat Jul 11, 2020 9:13 pm
Any mini gearbox will physically fit a 1275 block, only early 3 synchro cases need modifying for clearance according to gizzard book, as yours is a 4 synchro casting can’t see an issue, as you have had it rebuilt then it will be strong enough for a standard 1275, I would think fitting a 3.44 diff would help with the larger engine for cruising,
Excuse my ignorance but what is gizzard book?
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:46 pm
by Spider
Southwest wrote: ↑Sat Jul 11, 2020 9:30 pm
Daz1968 wrote: ↑Sat Jul 11, 2020 9:13 pm
Any mini gearbox will physically fit a 1275 block, only early 3 synchro cases need modifying for clearance according to gizzard book, as yours is a 4 synchro casting can’t see an issue, as you have had it rebuilt then it will be strong enough for a standard 1275, I would think fitting a 3.44 diff would help with the larger engine for cruising,
Excuse my ignorance but what is gizzard book?
Maybe this one ?
https://www.amazon.com/Tales-Gizzards-G ... 0060009594
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 9:56 pm
by Southwest
Spider wrote: ↑Sat Jul 11, 2020 9:46 pm
Southwest wrote: ↑Sat Jul 11, 2020 9:30 pm
Daz1968 wrote: ↑Sat Jul 11, 2020 9:13 pm
Any mini gearbox will physically fit a 1275 block, only early 3 synchro cases need modifying for clearance according to gizzard book, as yours is a 4 synchro casting can’t see an issue, as you have had it rebuilt then it will be strong enough for a standard 1275, I would think fitting a 3.44 diff would help with the larger engine for cruising,
Excuse my ignorance but what is gizzard book?
Maybe this one ?
https://www.amazon.com/Tales-Gizzards-G ... 0060009594
Mmm..probably more gearbox info that HAYNES!
Re: Engine Gearbox compatibility
Posted: Sat Jul 11, 2020 11:22 pm
by Daz1968
Sorry yes it’s vizard how to modify your mini, spell checker on iPad changed it, it shows early 3 synchro cases needing some grinding to clear the crank throw, but all later boxes should be ok. Book seems expensive though now, he my copy for years
https://www.amazon.co.uk/Modify-Your-Mi ... 0863430414