The 307 is actually has a CID of 316. Do the math. Chev decided to market it as a 307 (sounds better?). Early Modified Production racers used the bore/stroke combination with some success. In all reality a 307 done to the usual SBC standards has the ability to rock your world if that's what you want. The small bore isn't noticed in normal running and at high RPM the little bit of extra stroke pulls yer *** deep into the seat for what seems like forever. From 68 through the early 70s they were used in everything hooked up to the veneralble Powerglide and logged millions of miles. I think the bad rap is the lack of glamour ***ociated with the lil grocery motor. No 307 I've ever seen had a soft cam...that was the 305. In 76 through 1980 all 305 and 350s (from which ever engine plant) had soft cams. Story was they tried to heat treat too many at once. Had a 79 ****** that was pampered and religious oil changes, still wiped the lobes. Junk. Watch for valve intrusion on the small bore. I think 1.94s are the max for 307s. I can't recall. Basic hop-up like heads, cam, carb(s) and that lil motor will piss some people off when you tell em what it is. Like I always say, I never met a 307 I didn't like.
buy a new calculator 3.875 bore X 3.25 stroke is STILL a 307, not a 316 328 IF you use a 350 crank and can find pistons...
What is this going in, If you have a nice running 307 leave it alone. If your looking for some more HP's then build up a 350 no brainer. When was the last time you saw a 300 hp 307. SPEED COST MONEY-HOW FAST DO YA WANT TO GO.
http://www.jalopyjournal.com/forum/showthread.php?t=45615 http://www.jalopyjournal.com/forum/showthread.php?t=242405 http://www.jalopyjournal.com/forum/showthread.php?t=302087
Dont redesign the wheel, and dont listen to people tha tell you a 307 is junk, we go lo 12's all day with a 307 @3100 lbs. punch it .030 for 311"s use hyper slugs use 305 HO heads use a 30/30 retro cam use a 180 manifold 600 dbl pmpr good ign system 15/8 headers 26x9.5 slicks. as much gear as you need to trap at 6200. 12.40 @102 mph, shifting at 5800.
I'm running a 307 with a powerglide and the usual 4-barrel carb, mild cam, and headers upgrades and it runs great, better than the factory four barrel 350 that was in our '71 SS. The "experts" point to weak block castings and the two bolt mains as problems for the 307 but, if you're not thrashing it weekly on a race track I doubt you'd ever have problems. Bonus is you've already got it. Cams, intakes, and heads are same as anyother SBC, so pick you parts smartly and go to town. It'll surprise people, trust me.
Nope 327 is a 3.25 stroke, 283 is a 3", and yes the 307 and 283 share bore sizes Set up right there is nothing wrong with a 307, they were made in the 50's and 60's and worked my '64 M/T catolag even sells a 4" stroker crank for SBC, so imagine a 283/327 punched out mabey sleeved up to 4.125 or so, with that, you are talkin way over 400 cubes years before the 400 Small block
My son at 16 needed a cheap motor for his car so we bored a 307 to 4 inch used a set of L82 Std.forged pistons with a 882 head ,today he's 36 and yes the 307/350 with 83,000 stil is running well. If I remember the block had an "H" casting on it, but that was 20 years ago.
Use the 307 crank in the 400 block and have a 348, alot of guys run these in sand buggys, high revs and decent cubes.
Here are excerpts from a story sometime back. Maybe it will help, maybe it won't. "The engine in question is built upon an original '69 DZ 302 Z/28 4-bolt main block. The idea behind using a factory 302 block is to build it with a high-quality aftermarket rotating ***embly, valvetrain, and cylinder heads while maintaining a period correct cross-ram 302 intake and '60s visage. Basically, the high-tech parts had to be disguised under the garb of Hugger Orange and an OE factory look. The original 302 block has been bored .040-over; the cylinder bores measure 4.040. Also, the block has also been decked .025-inch. The current displacement measures in at 333 ci. The connecting rods that were used are lengthened Oliver 6.250-inch-long parabolic beam with full floater lightweight wrist pins. Compare the length of the Oliver rod with the length of the stock 5.7 rods. The pistons being used are SRP/JE forged 12.5:1 The crank that John chose is a Callies 3.250-inch stroke lightweight crank... After the linkage adjustment and some timing adjustments, another pull was made to 7,500 rpm and the lovely numbers popped up on the screen. At 5,600 rpm, the torque peaked out at 458. Peak horsepower topped off at 534 at 6,700 rpm. Like the original Z/28 race engines, this ****er is a high-rpm beast designed to run on race fuel. "
The Jalopy Journal
