Chevy 307

[dakeido]

Hi there haven't been on in a while. Just got a 307 off one of the guys at work for free. I know it is a 69-73 casting with 76cc heads. I was thinking of putting a lil love on this given the price and the fact i have some 64cc heads available.

Any ideas, would greatly be appreciated. If you recommend a 350 don't bother responding and no i will not be using for a boat anchor( sorry. had to get that out of the way) Just curious if anyone else has played with these motors and what kind of results they got.

thanks dave.

 

[42chevy]

I would much rather have a 307 than a 305. I think it should be easy to get decent power out of. I like a different engine. I run an Olds 350 in my Chevy and it gets no respect from most also, but is great and moves my car fine. Your 307 will be fun.

 

[zzrodder]

The 307 will respond to hop-up improvements just like any SB Chevy. They got a bad rap in their day mostly because of the crummy cam cores GM used around that period - lobes went flat, people beat on them harder to keep up and a lot of them got trashed. Upping the compression is a good start, some more cam and a dual plane manifold and you'll have a great hot rod engine. Don't go too big on valve size or cam duration, they don't need it to perform well.
307's never acheived the iconic status of the 283's and 327's which is too bad, another reason is that there was never a Hi-Perf version, they were mostly 2 barrel engines as an entry level V8, one step up from a 6 banger.
Go for it and prove the naysayers wrong !!

 

[R Pope]

A 307 is a 283 with a 327 crank, so all the 283 tricks work. Valve size is limited by the 3 7/8 bore, but otherwise its just a small block. A 283 with torque!

 

[rustybeercan]

Free is always good and increasing squeeze is an easy way to make more horsepower! Slip in a nice cam & off you go!

Beercan

 

[donsrods]

And when they are buttoned up hardly anyone can tell the difference between a 283, 305, 307, 350, 383, etc. Nothing wrong with that 307 at all, especially free.

Don

 

[FlatBroke]

I second what everyone else has already said...
And @ that price, you are already ahead of the game.

 

[dakeido]

thanks for the encouragement. can`t wait to get this thing on the engine stand.

 

[donsrods]

I've used a lot of preowned engines over the years and might make a few suggestions as to what things I have found are wise to do before installing one. (It is so much easier to do these out of the car than once installed)

1) First of all, take a compression test to see how healthy each cylinder is in relation to the other 7. Not so important to have really high numbers as it is to have even numbers (within 10-15% across the board).

2) Look at the overall condition of the motor........pull the valve covers, look for sludge, look for oil, intake, and water leaks.

3) Check out the freeze plugs for signs of rusting and seepage. Sooooooo much easier to change them to brass versions while out of the car.

4) Drop the pan and clean out any sludge in there and change the oil pump and clean the screen. Oil pumps go for a zillion miles, but a new standard pressure pump only goes for about $ 20 (Buy Melling) so it is cheap insurance. You don't need a high volume pump, I don't even use them in high performance motors.

5) While the pan is down, remove the crankshaft harmonic balancer, the timing cover, and check the condition of the timing chain. Even if it looks good, replace it with a double roller chain version. Don't buy a house brand chain setup, use a good brand. I learned that one the hard way, even new ones have slop in them if they are a cheap chain. The name brands fit so much tighter.

6) If you are so inclined, this is the time to replace the cam and lifters with a good mild cam. Something like an RV grind will keep your 307 cylinder pressure up, and give you a real seat of the pants boost in performance. Do not use the old lifters, and lube the entire new cam with lots of something like Comp Cams lube, and use an oil with lots of zinc, like Shell Rotella T, especially on break in.

7) If your motor has electronic ignition the only things that you need to do to tune it up will be cap, rotor, wires, and plugs.

8) Degrease everything with silicone and grease remover, and either paint it with a bug bomb engine enamel or with regular car enamel over epoxy primer.

If you do those things, plus replace some outside items like water pump, you should be good to go. I know it seems like you will be spending some money here, but you are in the motor free and you will reap the rewards with more miles of troublefree motoring if you do these up front. Every time I didn't do these things something bit me in the butt later on.

Don

 

[Gearhead10]

A well built 307 can turn circles around most others. They got a bad rap and most were overlooked for performance but they are a good little motor .

 

[dakeido]

Don thanks for the reccomendations. definitely going thru the old motor once i get it on the stand. now i need something to put it in..... hmm??!?!??

 

[lowbuckrats]

Had many 307's. Great all-around motor. Put in a summit RV cam & timing chain, decent dual plain intake w/ a latemodel quadrajet, headers, an HEI and your done. Get good power and excellent gas mileage, usually 20-25 mpg especially with a 700r4 behind it. Had this setup in my old 60 Biscayne for 6 years and is still running strong today with the new owner. Highly recommended powerplant.

 

[jensens ratrods]

im puting a 307 in my 53 f100 no time to work on it yet waiting untill winter to get laid off. i also got it for free ran good in the 86 caprice it has a 4 barrel .my freind calls them throw away motor . took it out and put a 350 in his demo car. lot of work just to smash it up.

 

[lowbuckrats]

im puting a 307 in my 53 f100 no time to work on it yet waiting untill winter to get laid off. i also got it for free ran good in the 86 caprice it has a 4 barrel .my freind calls them throw away motor . took it out and put a 350 in his demo car. lot of work just to smash it up.

You have the Olds version of the 307 from the pics, different animal. Don't expect a whole lot of power from these boat anchors. I had a couple and they nothin but made alot of cam noise and burned and leaked lot of oil and got terrible gas mileage. Worst motor ever made by GM in my opinion. On the other hand, the tranny behind it is pretty good. Should be a universal bolt pattern TH2004r overdrive tranny. Not trying to be mean to you or anything, just being honest and truthful from experience by me and my friends with these motors.

 

[BigIrish]

Out of curiousity, what is the difference? I thought GM pretty much used the same small block across all thier lines. Worse quality because of the years it was made or something different with the design?

 

[FlatBroke]

The oldsmobile line "Technically" never made a small block, even though they have the 305 / 307 ci motors.

 

[26Troadster]

gm is or was made of different companies, and each at one time had their own motor design. find you a old chilton's manual that has all the different makes and check it out, theres alot more then the chevy and fords.

 

[zzrodder]

Those Oldsmobile V8's were used in a lot of other 80's GM cars, Chevys,Firebirds, Buicks, some Caddys, the diesel version was even used in pickups. At one time GM had 5 completely different 350 V8 engines in production Chevrolet, Buick, Pontiac, Oldsmobile and Cadillac. In Canada, Pontiacs commonly came with Chevy V8's right from the mid 50's, in another odd move, some mid to late 50's Chev trucks came with Nailhead Buick engines. Even Oldsmobiles got Chevy V8's in the 80's.
Some buyer backlash happened when they found out - dedicated buyers of a certain GM brand were ticked off to find their new car had an engine from a different brand. This was fueled further by some spectacular flops like the awful dog Turbo Trans Ams with their turboed 307 Olds engine, a real turd.

 

[lowbuckrats]

Those Oldsmobile V8's were used in a lot of other 80's GM cars, Chevys,Firebirds, Buicks, some Caddys, the diesel version was even used in pickups. At one time GM had 5 completely different 350 V8 engines in production Chevrolet, Buick, Pontiac, Oldsmobile and Cadillac. In Canada, Pontiacs commonly came with Chevy V8's right from the mid 50's, in another odd move, some mid to late 50's Chev trucks came with Nailhead Buick engines. Even Oldsmobiles got Chevy V8's in the 80's.
Some buyer backlash happened when they found out - dedicated buyers of a certain GM brand were ticked off to find their new car had an engine from a different brand. This was fueled further by some spectacular flops like the awful dog Turbo Trans Ams with their turboed 307 Olds engine, a real turd.

Right you are zzrodder. Another oddity is the the late 50's GMC trucks using Pontiac v-8's. Also that turbo trans-am you are talking about actually used a narrow deck Pontiac 301 engine(called a 4.9 liter by the Co.).Had one those boat anchors at one time too.

 

[zzrodder]

Right you are zzrodder. Another oddity is the the late 50's GMC trucks using Pontiac v-8's. Also that turbo trans-am you are talking about actually used a narrow deck Pontiac 301 engine(called a 4.9 liter by the Co.).Had one those boat anchors at one time too.

Hmm, you may be right about that turbo engine, I do recall seeing the heads off one though, incredibly tiny restricted intake ports which totally choked off any chance of the turbo making anything close to decent power. What were the engineers thinking (or drinking?)? A mild Chevy 307 with a 4bbl on it would smoke it.