I'm watching Horsepower TV and they bored a 302 out .030 over to 306. Fairly basic build, single plane manifold, Holley 600CFM carb, and they are hitting 400HP and a decent amount of low end torque.

I have a 1990 305 TPI GTA that runs great (77K miles) but I'm wondering why this motor can't be made to do the same as the small block Fords?

I understand the top end would have to go, but it just surprises me that Ford seems to do such a good job with so little cubes. Can SB Chevy's do the same?

Just seems to frustrate me that everyone says don't bother with a 305 and go to the 350.

I'm hosed anyway because I have a 5 speed stick and don't want to break it with too powerful of a motor, but the rest of you should be able to do better. Maybe there is a way to make this a high rev'ing motor with lots of high and and less torque to not destroy the tranny?

 

You easily can if your 305 has a 4" bore like the 302 does, but then it's called a 350.

 

Destroke a 350. The Chev 302, 327 and 350 all share the same bore. The only difference is stroke. Bore makes HP. Stroke makes torque.

The 305 has the same stroke as the 350 but has a considerably smaller bore.

 

Yep. It is the bore to stroke ratio that limits a GM 305, not the actual cubic inch amount.

 

Moreso the absolute bore size, which limits the size of the valve you can put in it.

 

Thanks for the explanation. It makes sense now.