project: chevy 307

[bondm]

These "step-child" engines have powered chevelles, camaros, NOVAs, and who knows what else, since 1969. I've looked all over the internet for hopped up chevy 307's and can't find a single one! Everybody's advice has been, "scrap it and build a 350 - 307's are just too small..." Well not everybody is after 400+ HP! I've decided to sell my .060 350 and all the parts I had lined up to build it, and instead build up the little engine that could for my 72 Nova. I'm going to squeeze 300 ponies out of her and she'll be a fun, fast, loud little muscle car - just for the satisfaction of telling people what I've got under the hood. If you have any input or suggestions on head/cam/header combos I should consider, please feel free to email me here or at [email protected]

[timberdoodle]

thats an unfortunate story

[MagicRat]

Oh, jeez, man, why bother? It's like picking a bar fight with one arm in a cast.

These things have the bore of a 327 with the crank from a 283.
They can build for modest low end power, but will never get 300 hp if built like that.
They are a short stroke engine, so try to build it like a 327. Toss the original heads and try a 2.02 head. Use a 327 cam, so it will rev, and a single plane manifold. You will get 300 hp, but it will all be up high.
But get used to the idea that bottom end power will be as soggy as day old corn flakes.

[firebird69racer]

NO its the other way around. It has the bore of the 283 and the stroke of the 327. The 302 in the Z-28 had the 283 crank in the 327 block in 67, and 68 then in 69 they made its own crank with the large journal for the 302. And they made almost 400HP but at around 6,000 RPM. Then chevy had all the 283 blocks and 327 cranks left after making the 302 they put them together and came up with the 307. In theroy it should make some torque as it has a kinda of long stroke and small bore almost like the 305 of recent, it has the bore close to the 265 and stroke of the 350. not to sure as to what combo would work but stay with heads that are made for small bore. look at what works for the hipo 283 in the late 50's to early 60's before they made the 327. hope this helped you out
good luck


Wade

[bondm]

I'm not planning on boring the engine at this time. Some people have told me that it IS possible to bore it to 4.0" w/o a problem because they've done it, other tell me it's impossible, but can't tell me what the min wall thickness would be or why they know it couldn't be done. I'm planning on putting ported vortec heads on it, a performer or rpm intake, I have headers and dual exhaust on it now, but am unsure as to what cam would make the broadest power band. I'm leaning towards the Compcams XE250. I have a race built TH350 in the Nova now with a 3.08 open rear end. That may change someday in the distant future when money isn't so tight. Then 307 came stock with 200HP and 230ft/lbs in my 72 Nova - so those improvements should put it close to 300HP wouldn't you say?

[macktoschool]

Well lets see; If you take a 307, which does have a 327 crank, and bore it to say, 327, then you in my opinion have a stock 327. 283 to 400 is a small block. Basterdize it as you will, but it still ain't gonna be too unique. Good luck anyway though.

[MagicRat]

Originally Posted by firebird69racer

NO its the other way around. It has the bore of the 283 and the stroke of the 327. The 302 in the Z-28 had the 283 crank in the 327 block in 67, and 68 then in 69 they made its own crank with the large journal for the 302. And they made almost 400HP but at around 6,000 RPM. Then chevy had all the 283 blocks and 327 cranks left after making the 302 they put them together and came up with the 307. In theroy it should make some torque as it has a kinda of long stroke and small bore almost like the 305 of recent, it has the bore close to the 265 and stroke of the 350. not to sure as to what combo would work but stay with heads that are made for small bore. look at what works for the hipo 283 in the late 50's to early 60's before they made the 327. hope this helped you out
good luck


Wade

I stand corrected on the bore and stroke issue.
At 3.875 x 3.25, I would not call it a long stroke motor. However, the valves and ports in the heads are small and do favour low end power.

A friend of mine drove his girlfriends Camaro about 20 years ago (it was old then) with a 307. He remembers it was a good low speed tire smoker,(torque) but was not at all fast since there was no decent power up high.

Your propsed modifications are correct, but for the money, they would work lots better on a 350.

[alexhaley]

if u really want to build a bad 307 u need to get information from a person who understands the SCIENCE of motors not heresay from glorified part assemblers--------------if u dont mind running higher octane fuel the sky is the limit. i personally have custom built 307 making 535 horse at 6,500 rpms and enough torque to snap your neck. also yor not gonna get that kind of power cheap!!!

[sub006]

If you get the heads, intake, cam, etc. to build a Z28 307, then take a few hundred pounds out of the Nova, with the right rear gear you will have a great street performer.
Not cheap, but satisfying when your "307" beats anything bigger.