Small minor changes will only result in small performance gains.
A 305 can be built up just like any other engine. But if you want a big gain from stock power
you will need to change pretty much everything that matters, to achieve that.
Compression ratio , cylinder head flow, camshaft, valve size, induction/exhaust system.
A 305 responds to all of this.
car gear ratio swap, transmission torque converter swap
A 305 is a great engine to supercharge too. The stock 305 short block is plenty strong for moderate blower boost and the increased power and torque this creates, as long as detonation is avoided.
A low engine compression ratio is best. Some 305' have dished pistons and a low 8.6:1 blower friendly compression ratio.
Some have a flat top piston and smaller 53cc chamber heads and 9.5:1+ cr.
A 305 can be hot rodded to over 400 horsepower in naturaily aspairated-high compression form and over 450 hp in supercharged form.
"cheap" is relative. Small changes ='s small result.
The ability of the stock 305 cylinder heads ports to flow large amounts of air is a big limiting factor.
All the stock 305 heads are lame. Some are less lame than others and respond better to porting improvements and larger valves. A cylinder head swap to a much better high flow cylinder head is a great choice too.
What is the casting number on your cylinder heads? (under the valve cover) The 4416 305HO heads have the most potential once ported. (generously)
The stock OEM exhaust system on your car is very poor and really limits power.
This is a major point of power improvment with changes.
A real 100 horsepower gain requires big changes from stock. ( you will be changing or modifying pretty much everything)
Last edited by F-BIRD'88; 01-29-2013 at 12:27 PM.