Re: More power out of a Chevy Small Block

Posted by Ron in Nebr on October 31, 2004 at 22:21:39 from (65.169.97.32):

In Reply to: More power out of a Chevy Small Block posted by J.D. Jim A on October 24, 2004 at 19:19:34:

The other posts were right, there's no replacement for displacement. But since you want to work with what you have, there are some things that can be done.
The 305's were underpowered, due to a poor bore/stroke ratio mainly(small bore and long stroke), but also because the bore was so small that the heads had to use fairly small valves and they were shrouded by the cylinder wall.
Depending on what year it is(is the motor out of a '91 Caprice or is that what you're putting it into?), the crank could have either a one or a two peice rear seal.
The 305 crank and rods would not be any weaker than the same year 350 crank and rods, since they're made from the same material. Granted, they would not be nearly as strong as the crank and rods out of, say, an early 70's 350 out of a Z-28, but they'd be plenty strong for just a mild power improvement. The 305 used the same stroke as a 350, and apart from a slight difference in balance due to the smaller pistons, the 305 crank is almost visually identical to a 350 crank.
Since you said you wanted "cheap" power, your best bet is to just do the old standard hot rodding tricks to help it breath better- improve the exhaust system(duals, free flowing mufflers, headers), get more air in(free flowing air filter), and if money allows put in a better cam. Keep in mind that this is a small engine, so a cam that's fairly mild in a 350 might be too much for the 305. Your best bet would probably be an "off-road" or "high tourqe" grind. Be sure to put new lifters on any new cam. Also get a quality aftermarket timing chain, since the stock ones were noted for not being degreed right for best power.
If a cam is too expensive, a cheaper substitue would be a set of 1.6 ratio rockerarms. These would open the valves faster and farther than stock and give a bit more airflow.
You can also add an aftermarket intake manifold for a bit more airflow, but with the limited amount of air going through the 305 heads this probably wouldnt help as much as it would on a larger engine.
Finally, unless it's computer controlled, you can get a kit to speed up the mechanical advance in the distributor, and then also play with advancing the timing a little. Be cautious here though, since the 305's had a tendancy to be prone to detonation, which will kill it fast.
Remember, regardless of what size it is or what brand, an engine's basically just an air pump, and anything you can do to help get air into and out of it easier will make more power.
Also, and I havent yet mentioned it, if you get alot more air goint through the engine, you'll also need a corresponding increase in fuel, which means richer jets if you have a carb or playing with the computer if it's injected.

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