[hischildbrian]

I have a 69 malibu with a 307. Is there a way I can build this motor to make it fast and durable at the same time? Will I need a new crank, new heads, borred block, what cam do I use? These questions and more. A machinist told me that I can use 327 stuff, I'm new at this but am willing to learn and ready to get started. Or should I just build a 350? Will someone that honestly knows what they're talking about please help!! THANKS.

 

[ktownkid]

Hello Brian-
Welcome to Team Chevelle!!!!!!! A 350 is a better choice than a 307........but if money is tight, you could build the 307.

Someone will answer your question soon......that knows more than me.

ktownkid (His child too)

 

[saturnstyl]

There is no replacement for displacement. When in doubt, bore it out.
Seriously, get a 350. You will get more bang for your buck by starting fresh with a bigger engine.

 

[DZAUTO]

All of the above is correct, no argument there. BUUUUUUUUUUUUUUUUUUT, since you ask, here is what you CAN do to a 307. First, a little background. A 307 has the same bore (3.875) as a 283 (57-67), and the same stroke (3.25) as a 327. Thus, a 307 is a stroked 283. ALLLLLLLLLLLLLLLLLLLLLLLL 67-earlier Chevy small blocks have the "small journal" crankshaft and the 68-later have the "large journal" crankshaft. The 307 didn't come out until 68, thus, your engine has the large crank. To bore a 307 all the way out (an additional .125 bore) to 4in (same as a 327 or 350) is VERY risky. But, a .030, .040, .060 bore is plenty safe. You can bore it and keep your crank, or, you can bore it and literally drop in a 350 crank. For example, if you bored it .060 and dropped in a 350 crank, it would be about a 338. Pistons for this particular displacement are NOT readily available. BUT, you could do this bore/stroke combination with .060 pistons for a 307 and then use the shorter SB400 rods. Then, just build it the same as you would choose to build any 350 (cam choice, intake, carb, etc).
Cost? Well, it would be more than just a standard rebuild for a 350 (the 350 is the cheapest engine on the planet to rebuild because they are so common), but that is just one of many things that you could do to a 307. If you want to just keep the 307 and not do a lot to it beyond a standard rebuild (which MAY require boring it to clean it up), then a bigger cam, 4bl intake and carb and a set of headers will certainly wake it up noticeably.

 

[Bomber '67]

Just a reminder, it was just a couple of years ago that John Beck (Pro Machine, Placentia CA) nearly won the small block Engine Masters Challenge with a stroked 307 (a very close third place I believe).

His combo was not all that exotic, it is listed in one of the Pop Hot Rod issues (sorry, I do not remember the issues to look up). One of his reasons for building an engine around a 307 block was that the smaller bore size was beneficial (less prone to detonation) when running higher compression on pump gas.

The main stake through the 307's heart was that it was an economy V8 from the get go, most had a two barrel carb. 307's never originally came with any sort of performance cylinder head etc.

Thomas

 

[novaderrik]

i think they ALL got a 2 barrel carb- i've never heard of a 4 barrel Chevy 307.
i believe the 307 replaced the 2 barrel 327's, and the 350 was used where 4 barrel 327's used to go. the 307 was later dumped in favor of weak sucky 2 barrel 350's, and in 76, the mighty 305 came on the scene.
i don't know how much power you can get out of a 307, but i do know they are dang near bulletproof in a daily driver economy application- similar to a Mopar 318 or a Ford 300 inline 6. they just don't die even when you want them to.

 

[ssal396]

IMHO, if you are talking about a new crank, heads, pistons,& boring it out, it wouldn't cost you a whole lot more to pick up a 350 block.. Like Tom said, it's actually going to cost you LESS for the 350 parts then it would to build the 307..

Again, just my.02
Scott

 

[Olle]

IMHO, if you are talking about a new crank, heads, pistons,& boring it out, it wouldn't cost you a whole lot more to pick up a 350 block.. Like Tom said, it's actually going to cost you LESS for the 350 parts then it would to build the 307..

Again, just my.02
Scott

That's what I was thinking too when I saw all the parts he's talking about replacing. The extra c.i. you get by starting with a 350 will probably give you the cheapest h.p. you can get.

I have seen quick 307's so it's not impossible. However, it seems like those who hot rod 307's are just doing it to prove that it can be done. It sucks to throw an engine away, but I really don't think you'll save all that much by using the 307, and the 350 has so much more potential.

 

[SS4speed]

Along with everything else that has been said, remember, the 69 is a fairly heavy car. It's always better to have more cubes when you have a heavy car. Easier on the engine and always more fun to drive.

Fred.

 

[Mali Blu]

Really,it depends on how fast you want to go.
I mean,is a 350 going to be fast enough? or do you need a 502??

Personally,in your situation,I would go the 350 route. I think you can get more bang for your buck with the 350, than trying to build a 307. Yet you can still drive it somewhat economically. That is what your looking for, right?

 

[hischildbrian]

Thanks so much to everyone for their input. I appreciate the wisdom as well as the willingness to help. It is a nice change to ask a question and not get the "I know so much more than you" attitude. Thanks again guys. I'll go w/ a 350!

 

[Matt church]

I have a 69 malibu with a 307. Is there a way I can build this motor to make it fast and durable at the same time? Will I need a new crank, new heads, borred block, what cam do I use? These questions and more. A machinist told me that I can use 327 stuff, I'm new at this but am willing to learn and ready to get started. Or should I just build a 350? Will someone that honestly knows what they're talking about please help!! THANKS.

Hello yes i think 307 are good engines i built one n put a 350hp 327 cam n new steel timing chain n gear in it and put a pair of small cc 305 heads on it that i ground out a lil ...n a quadrajet 4 barrel that a friend rebuilt on it she was a demon in my lil '78 monte carlo with 2.73 posi rear it just never ran out of power in high gear n could come off the line like you not believe for so few cubes idk about a 68 cuz i not sure about weight dif. But es a 307 can scream nothin like the sound out of dual exhaust with blanks n no cats5

 

[Matt church]

Hello yes i think 307 are good engines i built one n put a 350hp 327 cam n new steel timing chain n gear in it and put a pair of small cc 305 heads on it that i ground out a lil ...n a quadrajet 4 barrel that a friend rebuilt on it she was a demon in my lil '78 monte carlo with 2.73 posi rear it just never ran out of power in high gear n could come off the line like you not believe for so few cubes idk about a 68 cuz i not sure about weight dif. But es a 307 can scream nothin like the sound out of dual exhaust with blanks n no cats5

Scratch the 5

Hello yes i think 307 are good engines i built one n put a 350hp 327 cam n new steel timing chain n gear in it and put a pair of small cc 305 heads on it that i ground out a lil ...n a quadrajet 4 barrel that a friend rebuilt on it she was a demon in my lil '78 monte carlo with 2.73 posi rear it just never ran out of power in high gear n could come off the line like you not believe for so few cubes idk about a 68 cuz i not sure about weight dif. But es a 307 can scream nothin like the sound out of dual exhaust with blanks n no cats5

307 has same stroke as a 327 if you are not aware of that so a 307 crank will go in a 327 or vice versa long as its large journal im not sure on that but i think all 307 are large journal

 

[HKalin]

I wonder if he ever built the 307 up seeing the thread is from 2005.

 

[Billdini]

I have seen and owned quick (not fast) 307's. Add a decent cam, some 1.94 66cc heads (can't use 2.02) a cam in the 2.20 duration, quadrajet, aluminum intake or cast and decent tranny gears like a M21 or closer to a first with 2.9x and 3.42's and it will surprise you. The crank is fine for 6k redline however 5500 would be safer. Your cam will mandate that. Refresh it at stock specs or punch it .30 to clean up the cylinders. Add a set of headers (optional) and a 2 1/4 dual exhaust and have some fun.

 

[Billdini]

I wonder if he ever built the 307 up seeing the thread is from 2005.

Got me again😳

 

[Aml383]

I have a 69 malibu with a 307. Is there a way I can build this motor to make it fast and durable at the same time? Will I need a new crank, new heads, borred block, what cam do I use? These questions and more. A machinist told me that I can use 327 stuff, I'm new at this but am willing to learn and ready to get started. Or should I just build a 350? Will someone that honestly knows what they're talking about please help!! THANKS.

Depends on what you consider fast.
That's a pretty subjective and relative term.
Fast .
Can it be economically feasible to do some things to a 307 to make it "fast" ?
Yes
But again there's gonna be a line there where putting more money in it to go "fast "
Isn't worth it

Let me ask you a question.
What do you consider fast ?
What do you consider quick?
What are your goals for the car for atleast the time while the 307 is in it ?

As far a boring and stroking that motor and putting new top end on it id say that would be over that line im talking about.

How fast is fast ?

 

[Jim Mac]

easiest thing is just bolt on a 142 miniblower. my mid 70s 350 in my 66 wasn't a rocket, bolted on a blower and woke it right up. jim

 

[71350SS]

I wonder if he ever built the 307 up seeing the thread is from 2005.

Got me again😳

Thanks again guys. I'll go w/ a 350!

That was the last thing he wrote here,so it looks like he followed some good advice.At least some of these old posts are entertaining.

 

[DZAUTO]

Just an additional comment.
When I bought the 70 Malibu conv in 98, it still had its ORIGINAL 307, which was VERY tired. I promptly built a SB400 and replaced the 307 and sold it.
Today, I REALLY, REALLY regret doing that!!!
I wish I had rebuilt the 307 with a .060 bore and stroked it with a 350 crank (or, MAYBE, MAYBE with a 400 crank). But too late now. I would have then built is like a very nice 350---------------AND THE CAR WOULD STILL HAVE IT'S ORIGINAL, NUMBERS MATCHING ENGINE!!!!!!!!!!!!!
It was a factory 3sp on the column and I replaced it with a Muncie. I often think maybe I should have searched around for a HD 3sp to replace the original Saginaw 3sp. And instead of swapping the original 10bolt 3.08 non-posi with a 12bolt posi, just added an Eaton posi unit. Oh well, it's water under the bridge now.