[HDWRENCH]

Well, with skyrocketing gas prices, the 350 is out for me. I am now thinking of installing either a 305 or 307 small block in my T. While searching the net today, I found it somewhat difficult to find pistons for the 305 that were reasonably priced. And I couldn't find anything for the 307. Anybody know where I can get a decent set of cast pistons for either of these engines? I'd like to find something in the 8.5 to 9.0 compression ratio if possible.

[Youngster]

Where ever you're looking for parts, they are doing you afavor by not listing 307 stuff. These engines were plagued with problems such as bad cams, core shifts, and others. The 305 is a much better choice all around.

Ron

[HDWRENCH]

Yeah, and the 305 is much easier to find . Not sure if I will get one from a junkyard or try and find a cheap beater and pull the motor and trans.

[donsrods]

The question is, will a 305 get THAT much better gas milage than a 350? I think all things being equal, the 350 should be just as good, and maybe even better. The reason is, you could run a slightly higher gear ratio and the 350 torque will just loaf along, whereas the 305 will have to work a little harder.

I am getting 20 mpg + in my T with a 350. I run a 30 inch tall tire, and 3:00 gears. Going down the road at 60 my foot is just resting on the gas pedal, not really pushing down much at all. I can see my carb right in front of me, and it is just off idle at those speeds.

Plus, 350 stuff is available all over the place, cheap. This isn't to say the 305 isn't a great engine, it is, but if you haven't bought it yet, just something to consider.


Don

[Mike]

I agree with Don, 100%. The difference in fuel mileage is going to be pretty negligible, if it even exists.

If you're buying a second-hand 305, ask the seller how you will be compensated, should the heads be cracked (since they likely are).

The 307 was much maligned, but it was a small-bore block (3.875" bore) with large main bores, using the large journal 327 crankshaft (3.250" stroke). That actually was a fairly popular drag combination, using the early, small journal 327 crank in a 283 block. A lot of early C/ED's used that combination. The problem you would have would be finding a block that hadn't already been bored too far, after all these years.

I know there are a lot of people using 305's, but you are going to be better prepared figuring in the cost of a set of replacement heads, as nearly all the 305 heads we've ever seen have been cracked.

[GT63]

If you worried about fuel mileage, check out one a GM's RamAir EFI crate motors. They make good horsepower and the EFI will surely help with mileage.
http://gmperformancepartszone.com/wi...html?cPath=1_2

[tfeverfred]

I don't know about the 307, but the difference in mileage between a 305 and a 350 would be little at best. Besides, driving habits would have to be considered.

Now, the 305 ain't as cool sounding rolling out of your mouth and they have been known for small exhaust and intake ports, but consider this.... just how fast are you trying to go? Are you goin to be racing it or displaying speed a lot? Then, I'd say, 350. Lot's of god, cheap tricks for bumping one up. If you want a nice, still kinda quick, easy to maintain AND replace (if you had too) engine, then the 305 could be what you want. I was going to go with a 350 out of a Vette, that a salvage guy was holding for me. He wanted $650 for it. He called and told me he had a couple 305's I might want to look at and they were only $400 each. Mine runs great. Moves my car plenty quick and is STOCK. Heck, I'm even running the stock Quadrajet carb! Why? Because it works. I haven't even rebuilt it yet!

So, you got some fuel for thought. Good luck. Oh, another thing.... if you get the 305, just SAY it's a 350. Chances are, no one will know the difference, anyway! What are they gooing to do, write down the casting numbers and check them out!? Please. There's a whole lot of guys TELLING how much fancy speed stuff they have in their engine and are running stock or near stock gear! Can anyone tell if an engine has a certain brand/type pistons from the outside? I kinda doubt it.

[bill4u6]

maby think along the lines of a 700r4 with a lock up t/q and a 350 you will get good fuel milage with this combo

[v8danh]

i have to agree with Don on this one .i experianced this when i built my last 305 for a chevy truck i had. it ended up way under powered and drank gas like an alchoholic drinks wine.lol i said right then i would never build another 305.i like you wanted better gas milage and ended up with a truck i was happy to get rid of.

[tfeverfred]

Originally Posted by v8danh

i have to agree with Don on this one .i experianced this when i built my last 305 for a chevy truck i had. it ended up way under powered and drank gas like an alchoholic drinks wine.lol i said right then i would never build another 305.i like you wanted better gas milage and ended up with a truck i was happy to get rid of.

What carb and intake were you running?