435hp Olds 307!!!
- Thread starter theoldsone
- Start date
- Status
Opie Knievel
Rum Fueled Midnight Mechanic and Moderator
I remember seeing this engine in the Engine Masters Magazine several years ago. It is pretty impressive to coax 435HP out of a 307, especially using the stock heads! I'm really impressed how much work went into building this engine. The article said they were on a budget. I guess that's why there was so much modification done to the heads instead of having a set made. I'm surprised that they reduced the size of the runners so much and still got 195cfm of flow on the intake side. I wonder what this little engine sounds like. Did anyone else notice the cam specs? It's got a pretty good amount of duration and a crazy amount of lift for a 307.
I know some of you follow motor trend, and the 305 is a little different then a 307 but the new engine masters they spray a bone stock 305, no ring gapping, stock pistons, rods crank to 650 flywheel HP. It then blew up when they added another 50 shot. But it depends on how you want to get there. Ultimately you could build a junkyard turbo motor for like less then 300 bucks, (I doubt it'll happen because ls truck blocks are so cheap)
At least a few people understand what I was getting at. It's a 307. I bet it had a real crackling raspy sound to it. Imagine that with some better heads and...well apart from the cam that's really the golden gate to HP. With some spray or a little boost we'd be looking at some numbers that most people wouldn't scoff at. Pushing the limits for any engine is fascinating.
Funny. Because I can't stay off Craigslsit I picked up a 86' 442 about a month ago. I saw that same article on the 307 build. He built a girdle for the block and raised the intake and exhaust ports a mile. I then found this article.http://tlentz.oldsgmail.com/more_power.html Although I just plan on keeping the stock 307 if I do change anything I will go straight to stage 4 skipping 1-3.
The early 307's were decent, more torque than comparable 305's. Remember Olds shocked everyone by coming out in 83 with the 307 HO that put out 180 HP, Ford and Chevy only had 175 HP. Olds should have done the FE3X mods to regular 442, the swirl port 307 was just a dog. Less compression and tiny ports, they should have added EFI and more compression to make it anything.
BUT the swirl port 307 was very reliable, had a good amount of tourque & 140 HP... It also functioned as designed and delivered great gas milage. I remember taking a trip from Boston to Allentown back in the day, we got like 25 miles per gallon on the highway. That was great for a big car back in the day..
+1 on this. And, the "Hypertech" chip is a complete waste of money. Been there done that. NO difference at all in performance. I mean => NONE! Now I did try a 125HP Nitrous shot on mine for a couple months and that made a noticeable difference but I knew the engine wasn't going to live long doing that plus it's dangerous. Details . . .
And despite, on this thread's build, the claim "they were on a budget", unless they just punted all their labor as "zero cost" this engine had to cost a ton of cash. Then there is still the part I don't get is "how do you make this much power with that little air flow without Nitrous or Forced Induction?". The numbers don't crunch. Putting a cam way bigger than my big block cam with restricted heads seems kind of a waste as well. Now, I bet it sounds really mean.
Again, I appreciate the ingenuity of trying, but I am still highly skeptical.
Now, bullet proof the lower end, preferably stroke it a bit, open up the top end substantially, add fuel injection and forced induction . . . that would make some serious power and likely still live a while. But, again, way more $$$$ than I've got in my big block.
Nearly everyone who owned the swirl port complained of lack of power. I think the early 307 was actually more reliable and got nearly as good for mileage. We got 32 imperial mpg one trip and I got 26 imperial with mixed driving after a pile of miles from out 81 Delta 88. It had an early 307, TH250C and 2.41 gears I believe. Even the 200 HP FE3X swirl port version would have been decent and helped with the dog reputation.
Last edited:
- Status
Similar threads
