Steve Hoelscher
True Classic
I have been asked about modifying the 3-4-5 sychros to a blocker ring type to replace the OE Porsche Type. This is not small project as I have actually investigated this previously. Make such a change would require designing a new slider hub that can accommodate the blocker ring type synchros, a new slider for the new hub and blocker ring synchros and then redesigning the gear.
For the gear, the engagement ring is pressed onto a splined hub that is part of the main gear. That hub could be pressed off and a new blocker ring type hub machined and pressed on.
CAD design tools and CNC machining makes this a much more feasible project now. That said the cost of design work alone is probably $25K. CNC Machined parts $250+ each for the slider and hub and also for the blocker ring hub. Then you would have to find a blocker ring that of appropriate size. It would actually be easier to find a shop that could reproduce the OE parts with greater quality. Or, develop a kit to adapt and alternate transmission. The Toyota C52 from the MR2 comes to mind. It has similar ratios and packaging.
For the gear, the engagement ring is pressed onto a splined hub that is part of the main gear. That hub could be pressed off and a new blocker ring type hub machined and pressed on.
CAD design tools and CNC machining makes this a much more feasible project now. That said the cost of design work alone is probably $25K. CNC Machined parts $250+ each for the slider and hub and also for the blocker ring hub. Then you would have to find a blocker ring that of appropriate size. It would actually be easier to find a shop that could reproduce the OE parts with greater quality. Or, develop a kit to adapt and alternate transmission. The Toyota C52 from the MR2 comes to mind. It has similar ratios and packaging.