Chevy 305 with 3 speed convert to 4 speed?

[NOSAJ]

Got a ‘72 40 that I bought years ago and po put a Chevy 305 mated to the stock 3 speed and transfer case. I have a 4 speed sitting in the shop. Assuming I’ll need a specific Chevy to 4 speed adapter, different flywheel, different clutch, clutch fork, TO Bearing, slave ?? Also I read the 3 speed t case can be converted to 4 speed? Then I’m assuming cross member has to be moved for extra length of the 4 speed? And drive shafts lengthened or shortened?


Trying to get my head around all involved.
Might just sell it…
Any help appreciated

Jason

 

[pb4ugo]

I think you'll need either a Downey or AA bellhousing. 4 speed fork and bearing hub/retainer. Sbc flywheel, disc, and low profile pp and Toyota throw out bearing. It's been a long time since I ran a stk 40 4 speed, so I could be off.

 

[jim land]

Maybe you will need new engine mounts if the conversion was done with the old Downey cradle mount or if the location of the engine is not as it should be

 

[bikersmurf]

Engine will likely need to be moved if it’s not far enough from the firewall. Drive shafts will need to be lengthened and shortened.

As stated, custom bel housing, clutch, fork, 2F throw out bearing, etc.

I’d sell it as is unless you are planning to keep it. Probably would not recoup the cost of the conversion. LS swap could make sense. 305s aren’t sought after.

 

[NOSAJ]

Thanks so much guys! I appreciate all the help! Looks like I got a lot to think about!

There was an adapter in classifieds I was thinking about but only one piece of a pretty big puzzle. I’ve always been more of a purist and this truck has just sat in the barn waiting. It’s pretty rust free from AZ. I guess if I’m going to change the tranny I might as well go ahead and do an engine and transmission I like if I decide to keep it. I drove it some before storage with stock tires and it drove ok kinda grindy and old dump truck feel. I’m more used to a 2f and 4 speed in my ‘77. Maybe larger tires might help some?

Thanks!
Jason

 

[peesalot]

I agree, if you are doing that work get an ls in there or a Toyota motor of choice. You might be able to find a complete set up with 4 speed or better and get a splitcase too which would save alot of work.

 

[pb4ugo]

I agree, if you are doing that work get an ls in there or a Toyota motor of choice. You might be able to find a complete set up with 4 speed or better and get a splitcase too which would save alot of work.

^^^^^^^^This^^^^
If your changing going LS, 350/383 or something else your tranny/tcsse options open up. I'd lose the 1 piece tcase, and run something stronger with more low rsnge gearing options