The bottom of a 305 is basically the same as a 350 so anything that can be done to a 350 CAN be done to a 305 but for the most part it does not make sense to do so. The primary difference between a 305 and a 350 is the bore size 305=3.740, 350= 4.00 inches. no the 305 can not be bored out to the 350 size (economically) there are tons of cheap parts available for a 350 and almost no performance pistons etc for a 305. Even having to buy a block it would still be cheaper to build a 350 (especially a stroker)and you end up with more power as a bonus..........Dan

 

:?

 

RHS offers complete stroker kits just for this.Your displacement will depend on the bore size.If you were to bore it +0.030 your displacement would be 334 cubic inches.Before investing in a blower i think i'd spend money on a good set of heads.Don't try to use big valve heads with big combustion chambers however.Stick with something with 1.94/1.50 valves and no bigger than 64cc combustion chambers.Just my opinion on the heads though.

 

the difference in valves between 1.94 and 2.02s doesn't really make a different unless you are turning higher rpms.

however. you may not want a 64 cc chamber head because it will raise your compression ratio, and if you're super charging, you may not want that. although pretty much all popular brands of heads have performance heads with 64 or 76 cc chamber heads.

but i agree, after doing cam and rocker work. thats the next big power adder. the heads.

 

1.94's won't work in a 305. Bore is too small. On some engines that don't actually contact the wall with the valve shrouding is so bad taht it runs better with the 305 heads.
Can a 305 be stroked, sure. Any engine can be stroked, but why?

 

Why would you want to spend the money to stroke a 305 when you won't get more than 334 inches? Do you know what's involved in stroking a small block? Although it's doable, it's not an economically wise decision...especially if you plan on installing a blower. Smaller bore, smaller valved heads, more air? You would be better off just using a 350 (4 bolt main block) and either leaving it a 350, stroking it, or stroking/destroking a 400 .

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While i'll agree that stroking the 305 is not the most economical thing to do,some of us have smog laws that warrant leaving the 305 in place and finding power with the existing engine.1.94 valve heads will work on a 305!In fact if you were so inclined you could use Trick Flow twisted wedge heads with 2.02 valves.Due to the combustion chamber design of these heads the valves will clear the small bore size.I have seen these heads bolted on a dummy 305 block and looked up the bore.You wouldn't want to use a big lumpy camshaft though.There is a good amount of shrouding.World Products sells 305 Torquer heads and they have 1.94 valves.I have been researching power adders for my 305 due to the smog laws here and am not convinced the 305 is as useless as some would have us believe.If you have lax smog laws i would just put in a 350 and be done with it.If keeping your car as stock appearing as possible and your block must be stock you can make a 305 run pretty decent.

 

Why is the 305 Chevy considered a "POS" by most people when there is a whole magizine devoted to the Ford 302 (5 liter) that often shows engines with 500hp plus. How different can they be! :?:

 

Bulletman why in the world would you take a 305 and bore it out when the stock bore and stroke on a 350 would net you more cubic inches. The cost of a stroker crank and boring on that 305 would easily exceed the cost of a rebuildable 350.

 

Before going on your rant next time read the text. I know they will phisically bolt on however do to the close proximity of the intake valve to the cylinder wall, 1/3 of the valve is totally ineffective.

The point is no way no how will you ever make anywhere the power with a 305 that a 350 will do with the same monetary investment.

Smog laws have nothing to do with anything. Any vehicle that has a 305 can just as easily have a 350, they are phisically the same exteranny and would require running numbers to tell the difference. Nobody runs small blk numbers to see what size it is for a smog check.

Yes, a 5.0 Ford is a totally different animal. You could say the same about the LS1, it is a 350 is it not. Yet it produces 500HP easily in full street trim and most smog cops wouldn't know the difference. To make a an LT produce 500HP would require some serious cam and anybody in town would know it. All engine families are different and respond to mods differently.

 

Perhaps you should read more carefully before you rant.I never suggested that the 305 will produce as much or more HP as the 350.I was simply stating that if stuck building a 305 you can use 1.94 valve heads.Coming from California i figure your smog laws are even more strict than ours.I just don't want any trouble with my car being legal.Smog laws don't have anything to do with it?That means if i do an engine swap and have any problems with the smog police i'll tell em to just call you and you'll clear everything up.

 

As A smog tech I will tell you swapping a 350 into a g body originally with a 305 will not raise an eyebrow. It is done all the time.

 

Perhaps you should read more carefully before you rant.I never suggested that the 305 will produce as much or more HP as the 350.I was simply stating that if stuck building a 305 you can use 1.94 valve heads.Coming from California i figure your smog laws are even more strict than ours.I just don't want any trouble with my car being legal.Smog laws don't have anything to do with it?That means if i do an engine swap and have any problems with the smog police i'll tell em to just call you and you'll clear everything up.

Hey Guys I didn't mean to sturr up such controversy. I guess I better come clean here, :evil: I have a 4 bolt 350 in my 5 th gen. The 305 is actually going into a 23 T-bucket that will be more for show then performance, and hopfully allow me a little bit of fuel economy when on a long cruise. The reason I raised the question of stroking is because I have not found much tech info on this engine. There was an article in Hot Rod mag a few years back that took a 307 S/B and made a radicle mouse, I couldn't quite understand what the difference was and why a 305 wasn't capable of the same performance. 8)

 

305 Rebuild

8) I have a set of power pack heads from an early 283 Vett, that I have considered installing on this 305, although I understand when running a blower keeping the compression fairly low is important. After reading several of other bits of info from you guys, mabe the stock 305 heads will offer better performance. Although I am a 350/383 fan I have a spare boat anchor (305) that I want to use in my 23-T. :lol:

 

A 307 and a 305 are barely related unfortunately, the bore and stroke are completely different the 305 has a small bore (kinda) 3.740 and shares the 350 stroke 3.480 inches the 307 uses the same bore as a 283-3.875 and a unique stroke of 3.25 the 305 has a relatively small bore and long stroke by comparison so it makes better torque but less horsepower. The 1/8 inch smaller bore shrouds the valves more and limits its performance quite a bit more than the 307.............Dan