Black dawg
Registered User
anybody have any experience with one? power? mpg?
I have one available to me for cheap.
need to get the burb rolling again.
I have one available to me for cheap.
need to get the burb rolling again.
307 sbc
- Thread starter Black dawg
- Start date
sle2115
NRA LIFE MEMBER
I've had several of them. Not big on power, but not bad either. I have one in a 3/4 ton pickup and while it wasn't the fastest thing on the road or the most powerful, it ALWAYS got the job done! I had one in a 1/2 also and it did the same. My half ton was a convert with fairly high gears (was originally a 250 6 cylinder) and it got very good gas mileage, usually could break 20 MPG with no problems. It had a RV type camshaft and Eldebrock (Carter AFB) style carb, intake, etc.
They are great little engines and generally don't have much go wrong. What year is it? I know the 305 had head crack issues and soft cams, had to replace both on my parents 77 Monte Carlo when it was about 3 years old and only had 20K miles.
They are great little engines and generally don't have much go wrong. What year is it? I know the 305 had head crack issues and soft cams, had to replace both on my parents 77 Monte Carlo when it was about 3 years old and only had 20K miles.
Black dawg
Registered User
it is out of a 69 blazer, planning to put it in my 89 suburban, hope that it will do a little better on fuel than a 350.
sle2115
NRA LIFE MEMBER
Yep, non-emissions, had the heavier cast heads, pretty much indestructable from what I've seen. I wouldn't hesitate for daily use, decent mileage and good dependability, considering it runs good, etc. or if you were going to go through it.
as far as i know it was a predecessor to the 305 which is a 350 with a smaller bore. you can only go so far with performance since the valves can only get so big before you get cylinder wall clearance issues. sounds like that is not a concern for you so i would run it!
STOP.
before you go any further make sure of two things.
one. passenger side exhaust manifold might use the broad spaced rear outboard hole on the passenger side. you can use the earlier manifold in place of the late, but you will have to redo that section of exhaust.
two. flywheel bolt pattern between the two may be different. 307 iirc is an external balance motor and the flywheel may be unique. the number of teeth on the flywheel ring gear will determine what series starter you need.
before you go any further make sure of two things.
one. passenger side exhaust manifold might use the broad spaced rear outboard hole on the passenger side. you can use the earlier manifold in place of the late, but you will have to redo that section of exhaust.
two. flywheel bolt pattern between the two may be different. 307 iirc is an external balance motor and the flywheel may be unique. the number of teeth on the flywheel ring gear will determine what series starter you need.
sle2115
NRA LIFE MEMBER
307 is internally balanced, it's the 302 that is externally balanced. 302, 400, and 454 were all externally balanced. 307 is the same block as the 350 with a 3 7/8" bore instead of the 4".
Black dawg
Registered User
thanks for the info guys.
the 307 was a low compression, low hp and low Nickle block. Putting one in a Suburban may not get you a MPG improvement over a 350 because the 307 would be working harder to move the same amount of weight. All SBC's are internally balanced except for the 400.
sle2115
NRA LIFE MEMBER
Think you might be thinking of the 305...the 307's were pre-emission engines, built on the basics of the 3 7/8 bore on the 327 stroke. The 305's had soft cam issues as well as horrible cylinder wear issues and notorious for cracked heads. I've had my share of all of them! 307 in stock trim, while not being a power house, will run circles around a 305 in power and longevity. MPG versus a 350, not a great deal better, but usually a couple MPG better. I put one in my 79 chevy pickup while building a 350 and was actually pretty pleased with it. My cousin also had one in a 70 Chevelle that ran QUITE well!
Another **** was the 307 Olds. That thing would wear out bores in 40,000 miles. IMO a 305 will out run a 307 in a race. Advance the timing on the 305 ,remove the pellet cat and with it's 3.48 stroke it will squeek a tire on dry pavement. I've never seen a 307 that would squeek a tire regardles of tuning.
Now if you want to have a fast little ride. Get a 350 block and put a 307 crank in it. This makes a 327 large journal engine. Put 327 flat top pistons in it, double hump heads, a 350hp 327 cam or a Duntov 30-30 if you don't mind a mechanical cam, headers and a 4bbl then put this in a small car such as a Vega or Shoebox Nova(I'm showing my age here) with your choice of trans and 4.10's in the back then go Big Block hunting.
That short stroke 327 crank will wind up fast in a light car!
Mine was in a AMC Pacer! I was also running a 500CFM 2BBL Holley carb. Nothing like smoking the competition with a 2BBL carb! A Pacer is low but wide for it's size, handled fast acceleration very well, better than a Vega or Nova.
Now if you want to have a fast little ride. Get a 350 block and put a 307 crank in it. This makes a 327 large journal engine. Put 327 flat top pistons in it, double hump heads, a 350hp 327 cam or a Duntov 30-30 if you don't mind a mechanical cam, headers and a 4bbl then put this in a small car such as a Vega or Shoebox Nova(I'm showing my age here) with your choice of trans and 4.10's in the back then go Big Block hunting.
That short stroke 327 crank will wind up fast in a light car!
Mine was in a AMC Pacer! I was also running a 500CFM 2BBL Holley carb. Nothing like smoking the competition with a 2BBL carb! A Pacer is low but wide for it's size, handled fast acceleration very well, better than a Vega or Nova.
I had a 307, in a 73 Nova. Wasn't a fireball, but got right down the road. Mileage was what you'd expect, from a V-8, with a kid on the throttle. Outran a mid 80s Monte, with a 283, one night.
The 307 was a large journal engine, but was basically a 283 bore, with a 327 stroke. It was GM's 1st attempt at economy/emissions engines.
The 302 was a 327/350 bore, with a 283 stroke. Chevy's answer to the 305 cubic inch limit in Trans Am racing. Never had one, but a friend told me he had one, back in the day. It was a screamer.
The 307 was a large journal engine, but was basically a 283 bore, with a 327 stroke. It was GM's 1st attempt at economy/emissions engines.
The 302 was a 327/350 bore, with a 283 stroke. Chevy's answer to the 305 cubic inch limit in Trans Am racing. Never had one, but a friend told me he had one, back in the day. It was a screamer.
