In desperate need to upgrade the performance of my 69. Currently running a 305 with m21 tranny (unsure of gears) which tops out at 75mph(wtf)

Engine wise im either going stroker or 454 and if i were to go one of these routes what would be the best decision on the transmission and gearing to ensure im not embarrased by these little imports.

There is no replacement for displacement. With that said, if you are all set up for a small block, I would go with a 383 or a 406. No need to switch everything over for a Big block. For the trans. I would go with a tremec 5-speed if you allready are manual. Rear gears, I would go with a 3.73 : 1 ratio.

There is no replacement for displacement. With that said, if you are all set up for a small block, I would go with a 383 or a 406. No need to switch everything over for a Big block. For the trans. I would go with a tremec 5-speed if you allready are manual. Rear gears, I would go with a 3.73 : 1 ratio.

I think a 3.73 is a little low. The tremec has a 3.27 first gear and if you multiply these ratios, you get 12.2. You want it between 10-12. I have a 3.42 rear, this puts me at 11.2. I think this gear or something close to it will give you better results.

Just my opinion,

JR

Why worry so much about the first gear ratio? It would seem to me that you spend a whole lot more time in one of the other four. I would select a gear ratio that puts my engine in the right rpm range for the application.

60' time

Do they pay better for 60' times ? j/k I have 4:11 gears and a 700r4, and yes 1st is pretty low !

My 700R4 equipped car would 60' just as well with 4.10 gears as with 3.70 gears and run a couple tenths quicker in the quarter. Couldn't get all the motor in with the 3.70's, and you spend over half the quarter mile in third gear.