8 replies to this topic

[nightroamer]

Hi another silly question really.

i have a 1275GT Non A-Plus block number starts 12H 706

would i be right in thinking that th gearbox rato is actually different to normal? is it harder to find parts to refurbish it? is it better or worse than normal ratios??

many thaks guys

[benfredjosh]

hey i know hardly anything but i do know that the gt has closer ratios i think but guessworks will know hope that helps

[Bungle]

as guessworks is not here have a look at his site

[nightroamer]

cool cheers, so it looks like there is a little more speed through each gear from 1 to 3

[Guess-Works.com]

Correct, they removed a tooth from the first motion ( 4th gear ) which turns the laygear just that little bit quicker, which brings 1st 2nd and 4rd a little closer to 4th which remains the same ( as in all 4 speec mini boxes as 1:1 )

You can still get a conversion set from minispares which is the 1st motion shaft and the laygear for about 100 notes..

I have a couple of originals kickin' around the garage somewhere..

I actually have a set in grotbag at the moment, and believe it or not you do actually notice the difference, especially dropping to 3rd from 4th, because they are fairly close together ( not as close as a SCCR set ) there's not so much of a rev rise, so you dont end up thrashing the a**e of the engine... she'll do 80 in third no worries with a 3.44 diff

*edit here's a little graph which shows the difference between the A series ratios based on a gearchange @ 6500 rpm

Edited by GuessWorks, 23 December 2005 - 10:52 PM.

[nightroamer]

cheers guessworks your a legend! think i will keep the box and recon if needs be and then get morspeed to do the engine work on my block etc so i can stay with the 1275GT engine (well in the form of a 1380). that'll go in my city along with a set of shiny new 5*12 superlites ) thats all my money gone.

another q i have a set of twin HIF38 carbs, never seen twin hif's, are they good or over powered for the engine (just a morspeed sports 1380) apparently in very good condition as i had a friend take a look.

tom

[Bungle]

another q i have a set of twin HIF38 carbs, never seen twin hif's, are they good or over powered for the engine (just a morspeed sports 1380) apparently in very good condition as i had a friend take a look.

have you got any pics you can put up ?

i have never herd of twin HIF's

might they be strongbergs ? (cant spell)

[Guess-Works.com]

Most of the time twin HIF's are two RH units bodged together.... but

They did make Twin HIF6's which were fitted to the Rover v8 SD1's ( I have a couple of sets ) but they are 1.3/4" instead of the 1.1/2" (HIF38), you do still have to invent the linkages somewhat but it's a lot easier as they are LH and RH pairs...

I'm going to try a set on the 1330, but that's using high compression, long duration cam, and ported cooper head.. so may just be able to create enough flow..

[nightroamer]

cooli'm going to go check them out sometime his week and get picks but i think they have all there markings on them and linkage.