307 Questions

[TylerT/AZ28]

so, i cleaned my garage today and noticed i had an unusual collection of engine parts, consisting of a complete 307 without carb or intake, 305 heads and a 350 cam, and a few other things like a few starters, alternators, water pumps, and so on so forth. so the question is, can i build the 307 with the 305 heads and 350 cam? im pretty sure id have to buy lifters with the use of the 350 cam but im not at allo sure since ive never built an engine. all the parts were given to me the 307 came out of a 70 chevelle and the 305 heads of my 85 camaro, where the cam came from i dont have the slightest clue. so would my above mentioned combination sucessfully work at all? sorry for ranting on

[ezcruisn71]

You can use the 305 heads on a 307 engine. We need to have more info on the cam though. Like the lift and duration numbers. If it was a used camshaft without lifters then you probably would not want to use the camshaft. The lifters and camshaft should be a set. What I mean is that the lifters should go back on the same lobe of the camshaft that they came from. They wear together. So if the camshaft is new then put new lifters with the cam. If the cam is used then new lifters could wear the used camshaft out prematurely.
That 307 engine was only a 200hp engine in 1970 with 9.0:1 compression pistons.
That was the same engine that was in my first 1970 Camaro.
Can't put to much of a high lift or high duration Camshaft in that low compression engine.

[prorac1]

The problem with both the 305 and 307 are the small bore and restrictive heads. You probably COULD build it, but you would be better off selling or scraping it and picking up a 350 for a couple hundred dollars. Someone on craigslist would probably give you that much for the 305/307 parts. JMHO. Eric L

[TylerT/AZ28]

i know everyone hates the 305/307 etc but i like a challenge and im gonna see what i can with little expense on a smaller V8. so the heads can be use and the cam also as long as the lifter are the same shape. how about the crank, ive got a couple 305, 350, 327, and the 307. which one of those can i use? the 307 is pretty worn out and doesnt look too good.

[prorac1]

Nobody hates the 305, so dont get your panties in a bunch, lol. Performance is just not its element. To make power, you first need to understand how to make power. And bore is a BIG deciding factor. But, if you insist, ill indulge. You would have to find out what all the strokes are, and list it down. Do the same with the rod lengths and piston pin heidths. Find a combo that comes up to around 9 inches (which is your deck heidth, actually closer to 9.20-9.30) Take half the stroke, plus the center to center rod length plus the heidth of the piston from the center of the pin to the flat top protion of it. Could be fun if done right. Even beter if you want a challenge is use the large bore of the 350 motors and combine it with a smaller stroke 3.25 IIRC of the 307. The 305 has the same stroke (3.48) as a 350. The 307 has the same stroke as a 327, and the bore of the 283. Its kinda a backwards 302 small block. If you were to combine the bore of the 305 with the stroke of the 307 you would have a 328 ci small block. Throw some old home ported heads on it and see what happens. OR, just put together a pile of parts of whatever fits and see how much nitrous it will take before blowing rods out the pan. You would probably be suprised how much it would take. That would be SWEET. Theres my .02. This could be cool as long as you dont get to serious about it. People have done that in the past and ended up fighting a pointless battle that GM never intended to happen, lol. Eric L

[TylerT/AZ28]

ok i know i may be soundin a tad but difficult but if a 307 has a bore of 3.875 and a 305 with 3.736 then youd have to make it smaller wouldnt you or am i dumb

[prorac1]

I dont even know what your asking in that question, lol. The 307 and 305 are two totally seperate motors that happen to share the same archetecture. Eric L

[TylerT/AZ28]

yeah ive been looking into all small blocks and getting research done and i noticed that a 307 and 327 share the same stroke but the 327 has a 4.00 bore and the 307 a 3.875. now im thinking .135 is alot to bore an engine but can it be done on this one? i could just ry to make a 327 out of it, because the crank is the same and the only other difference are the heads and rod lentght which a 5.4 and 5.7

[prorac1]

No, you cant bore it that far. .040 or .060 is the most you can usually bore a small block depending on wall thickness. For something like $100 you can pick up a 350 core block. Put your crank and rods in it, buy some elcheapo $100 cast pistons and search for some old ported small block heads, or a deal on some vortecs. Eric L

[ThreeHonks]

No, you cant bore it that far. .040 or .060 is the most you can usually bore a small block depending on wall thickness. For something like $100 you can pick up a 350 core block. Put your crank and rods in it, buy some elcheapo $100 cast pistons and search for some old ported small block heads, or a deal on some vortecs. Eric L

x2. ditch that 305 or 307 or whatever it is. trash can here it comes!

[TylerT/AZ28]

i know you guys really want me to go the 350 route, but its so common and im quite an unusual person so im just gonna make a mutt of all engines. later on i want to get a 400 small block and build that for a project car of some sorts

[ThreeHonks]

stock 350 > modded 305

[prorac1]

No one is stranger than me, trust me. I built a tube chassis Plymouth Valiant with a Big block chevrolet. My first performance motor was a 225 slant six that put out around 300 hp. I know strange, lol. When it comes to small blocks, your not going to do anything that hasnt been tried before. Its been tried, and it dosent work. It may be a good conversation piece, but when the bull hits the pavement, it wont perform. And thats what it all comes down to. If you want to try it, look up to my first two posts in this thread and try one of those ideas. Strange is one thing, effective is another. Coinciding the two together is priceless, but rare, lol. Eric L

[JoeliusZ28]

i know you guys really want me to go the 350 route,ater on i want to get a 400 small block and build that for a project car of some sorts

No no no no. were not telling you you need a 350, were just telling you you need a 350 block.

If you want to be unusual get the 350 block and run a smaller stroke. You could do a 302 or a 327 with a 4" bore. Anything with a 4" bore is a better for making power than a small bore block. Bore > Stroke. (IE you could bore the 307 to a 313, and a 302 will still make more power). The small bore blocks are designed for making small power. Don't treat it like a challenge you can overcome. Im not sexist but it'd be like a girl in a powerlifting competition, the genetical foundation isnt there. Sure you can take on the project, but don't plan on having anything fast when youre done.

[ezcruisn71]

A 307 can be built to make good power but it is expensive.
A 350 can be built to make the same power a lot cheaper than a 307.
Here is a writeup were they built a 1968 307 Chevy in the Super Chevy Magazine.
So it can be done...
http://www.superchevy.com/technical/...nce/index.html

http://superchevy.automotive.com/521...nce/index.html