| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | The 305 flywheel might have a different bolt pattern. Which bellhousing are you going to use? The 305 might not bolt to the 366, also 420 retainer diameter might be too small for 366 bell housing. Many 366's have Clark 5 speeds, I have one.
Be best to determine all these issues first.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| 
