I was talking to someone that wanted to put a set of 69 307 heads on his 350. would that make any difference at all to the motor for the better? I don't know the castings of the 307. also he said that if you put a 307 crank into the 350 you would have a 327. 307 cranks were cast. how much could you rev that up to? thanks

 

This goes away back and I don't remember that much, but the 307 was a low performance engine. Putting 307 heads on a 350 block is a new one on me. I'm not saying it's wrong or bad, but we are talking about 35 year old technology.

As far as the crank goes, Chevy made the 307 by combining a 283 block (or at least a block with a 283 bore) with a 327 crank. So, at least theoretically, I guess you do get a 327 out of a 350 with a crank from a 307.

The question I have: Why?

 

he was saying the the 327 was more of a higher rev motor than a 350. he said it was the difference of a race horse to a work horse(327 compared to a 350). I have delt with 350's and 305's but not a 327. I was wondering if a 327 with a cast 307 crank would perform well. or is it just a waste of time to combine a 307 with a 350 block.


I know that most people say there is no replacement for deplacement but this is trying to see what could happen.

 

Unless you have no other heads available, and absolutely have to get the engine running before the asteroid hits your neighborhood, you're wasting your time. The 307 heads are likely a huge chamber, and might net compression around ½:1, maybe less. Well, maybe not quite that low, but it's a waste of time.

The 307 used a 3¼" stroke, just like the 327. There is little practical advantage to a shorter stroke any more. You can build a 350 to run 8,000 RPM all day long if you wish.

 

Never seen a piston go down on the upstroke before....

As far as the whole 327-350 debate (or destroking motors, for that matter), there's a pretty good sized thread in the engine swap forum - a sticky there, that ljnowell and myself started.

 

Wow. I just read that thread. I can't believe I read the whole thing. Too bad it didn't get locked after the first few posts. There is a lot of opinion in there, and a little science. I'd be tempted to unstick it, let it fade away into the oblivion of the archive with the rest of the threads, and post the good parts into another locked sticky thread. There are more eight second 327s represented in there than have ever existed on the planet. Memories are great, aren't they?

Back to the question at hand, 307 heads seem to have 74 or 76cc chambers, and necessarily small valves (like the 305) so you can imagine the flows.

 

ok so the 307 heads are about as good as a set of smog 305 heads. thanks for the info.

 

Worse, they are just about the worst.

 

It's a beaut, ain't it? I've thought about cleaning it up several times, but just thinking about it gives me a brain cramp. I've taking the tact of feeling comparatively intelligent knowing I possess superior logic to the majority opinions expressed there.

Small conciliation, but it's all I've got.

Oh, yeah - 307 heads: Pass. 307's were base V8's that were never given HP parts - you know, cam, compression, carb, intake - and yes, heads. . .

 

Should build a sweet motor with 307 heads and the LG4 cam.

 

Let me know if you want to go that route, I have a sweet rochester 2bbl, intake, and a points setup in my garage. It'll really scream then.

 

so the best setup would also have a set of 2.08 gears with a powerglide?