tylercamaro

iTrader: (1)

recently ive been given a 307 from a 70 chevelle with all the lower half all its missing is the intake and carb. in school im taking auto shop and theres an engine bore there so i was thinking maybe i could bore it to 327 because thats what my teacher told me i could do. anyways i dont really want to buy custom pistons for it so could i just swap in any 327 pistons? also could i use the 307 or 305 heads for better compression and a 350 cam. in other words would this work at all, or am i getting way too complex with this and just build it as a 307? sorry if i confused anyone

jwande

I believe 1974 was the last year that engines didn't come with hardened valve seats. The lead was a lubricant to prevent seat erosion. If you go with the 307 heads, take it to a machine shop and have them install hardened seats so you can run normal unleaded gas without having to add anything to the tank.

Apeiron

A 327 is a 4" bore engine. You can't put its pistons into a 307, which is 3.875" like the 283.

Lead was added to gasoline primarily as an anti-knock ingredient, the valve-seat lubricating properties were something of an added bonus. Under normal non-racing conditions, valve recession with cast iron seats and unleaded gas isn't that much of an issue. The 307 was never "performance" engine anyway (picture something around 200 gross HP), so it's heads aren't likely to be anything special. Casting numbers will tell all.

sofakingdom

iTrader: (1)

Sounds like you paid more than it was worth.

Throw that in the trash and go get a 350. It's not worth spending money on. A 350 core is like $50, if you even have to pay for it at all (I've given away my share of them); EVERYTHING about a rebuild costs the same, OR LESS, than a 307; and when you get done, you'll have about 15% more motor, for basically $0 more, when it's all done. Kind of hard to argue with numbers like that: arguing with numbers is a sure mark of a fool, anyway.

tylercamaro

iTrader: (1)

i see youre point about not much power and just get a 350 but i dont really want an engine everyone else already has, i was planning on buying another thirdgen down the road and maybe putting it in that or my camaro, but i was trying to stay clear of the 305, 350, 383 areas

sofakingdom

iTrader: (1)

A 307 is a 283 bore with a 327 stroke.

Take it from somebody who WAS THERE at the time, before the 350 became readily available, and we spent all our time and effort making chicken salad out of chicken .... something else ... from 283 and 327 parts:

The 307 is GARBAGE. In stock form, it was ALWAYS the low-HP, low-perf, low-everything, basic, Grandma's daily driver kind of motor. THAT'S WHAT YOU"VE GOT if it's original: think 4-cyl compared to L69, or 2.8 compared to 350 TPI; that's what the 307 was. Basically, the 305 of its day.

However even with the factory's crippling undone, like good heads and exhaust and such, it was not as good of a motor as the 302; and CERTAINLY not the equal of the 327. Which was roundly STOMPED by the 350 when we started being able to get our hands on them.

While arguably a better bore/stroke combo than the 305, it's still not worth sinking ONE RED CENT into. Like I said above, if you got it for free, you paid MORE than it's worth; because now you have to dispose of it. You should never have let it darken your doorstep.

DO NOT spend any money on it. 350 cores are just TOO CHEEEP. Even 400 cores (now if you want to be "different", THAT'S the kind of "different" that sets you AHEAD, instead of advertising that you're a short bus rider) are still cheeep enough and plentiful enough that a 307 is still just as much the same GARBAGE it always was.

Don't screw up and throw away a whole bunch of money polishing a turd. I will guarantee you, no mater how shiny you get that turd, it's still a ..... you figure it out.

tylercamaro

iTrader: (1)

well i believe sofakingdom just changed my perspective on this topic, maybe ill go the 400 route, does anyone know how much of a difference there is in a chevy 400 and a pontiac 400 if any?as for the 307 ill make a chair out of it or something

Apeiron

The only thing they have in common is that they're both V8s.

Sonix

iTrader: (1)

I just want to know this:

How does someone become an AUTOSHOP TEACHER --- IN MICHIGAN, who thinks this??? Since the 307 is a waste of time anyway, put it on the boring machine and bore it out to use 327 pistons... Then when you "run into trouble", go ask your shop teacher what's wrong... I'd like to see the look on his face...

Funny - My very first post on this forum was about souping up a 305 (because that's what I had), and if I recall correctly, RB83L69 -- or whatever his name was at that time, also reminded me it was a waste of time... Funny how things never change...
Hint - I "obtained" a 350 for a song (and that's in Canada! You should be able to get it for a stick of gum in Michigan!), and rebuilt that.

tylercamaro

iTrader: (1)

he actually gave me the idea, hes not too in tune with the whole high performance engine/v8 thing. in my car currently i have a built up 305 and im happy with that but its not super powerful or anything, i just want another project and want to go a more weekend driver route with it

RED86Z28

The 307 is not as terrible as its made out to be. Go .060" over and its about 316 ci with a 3.935" bore. It all depends what your goals really are since its plenty capable of producing power in the low 300s easy with inexpensive modern heads.

sofakingdom

iTrader: (1)

You're right... it's not that terrible.

It's WORSE.

Sure, it's capable of producing low 300s of HP, easily even. That's not the point. The point is:

For what it will cost you, drive-in to drive-out, to get low 300s out of that steeeeming pile of dung ($3000 - 3500 more or less if you buy new heads, or a few $100s less if you get used Vortecs), you can get low-mid 400s out of a 350, and high 400s to low 500s out of a 400!! All you have to do is spend a couple of the loose coins out of the pile on a $50 CORE. Same money, GOBS more HP!!!

How is the "free" 307 "a good deal"? EVER?

Allow me to repeat myself, at the risk of sounding like a skipping CD. DO NOT spend a penny on that 307 core!!! you might as well take your money out of your pocket and light it on fire; it will give you just about the same value and level of satisfaction.

Sonix is right: all of us old geezers on here who have some "been there and done that", especially from the days before Algore invented the Internet and the only way we had to communicate was to chisel it on a tablet of stone, will tell you THE SAME THING; because, we've all MADE THE SAME MISTAKE AT LEAST ONCE. Listen to him. Learn from our screw-ups that we're generous enough to share with you, even if somebody who has NEVER TOUCHED one of those old things is telling you what you want to hear. It's the sure road to an emtpy bank account and a car that's STILL slow after having a MAJOR WAD of cash dumped on it. And that takes the fun out of this hobby IN A HURRY.

tylercamaro

iTrader: (1)

i think ive been quite persuaded to not use the 307 i want to go the 400 small block route, i used to have one in my 79 trans am and then i sold the car, so question is whats the difference between a pontiac and chevy 400 if anything, and will my 700r4 bolt up to it with any problems? all the help is appreciated

sofakingdom

iTrader: (1)

Everything. Absolutely EVERYTHING is different.

Well I take that back... in certain years the spark plugs are interchangeable, and the dist cap and rotor; and you can use a few of the bolts here and there on either motor.

The bell housing bolt pattern is different (no 700-R4 has the right one since the Pontiac V8 disappeared before the 700 was introduced), the exhaust is COMPLETELY different, motor mounts are different, accessories (alternator, PS, etc.) all mount differently and usually in a different place or even on the wrong side, the starter is on the other side, and no castings interchange (intake, heads, water pump, or anything like that).

A Pontiac 400 isn't a "small block", and it isn't a "big block" either. It's a Pontiac motor. The 400 in particular IIRC was discontinued in about 1969 or so, so they're not just hanging from trees. After that, there were only the 350, 400, and 301 :barf:. They're all the same size from front to rear; all of em use the same cams and have the same bore spacing. However, the 350 and the 301 have a "short deck", where the heads are lower down toward the crank; so in that limited sense, the blocks for those are "smaller" than the others. But they're not "small blocks" like the 2 major divisions of Chevy motors or Xler or even Frod.

I would STRONGLY advise against attempting to swap a Pontiac motor in, if you don't even know what's different. While there's nothing "wrong" with them, things like that are best left to people who are familiar with them, what fits what and what doesn't, have access to old used parts laying around hoarded in people's garages, and such as that. People will tell you all day long, with a straight face even, abotu how they're "torque monsters", but the real truth is, they make about the same torque as any othe rmotor of the same size with similar induction systems. I.e., a 455 is only a "torque monster" to the extent that it has 455 cubic inches, and DOES NOT somehow extract more energy from the gasoline than a motor with some other word stamped in the valve covers. If you get some old smogger sedan motor out of Grandpa's old land barge that's been rusting away out in the back 40 since they took his license away in 1985, you'll have .... an old smogger Grandpa's sedan motor; NOT a "Ram Air" or any of those good, worthwhile ones. My advice at this point would be not to even consider a Pontiac motor swap, just put it out of your mind. NO WAY it will be "economical" in any form or fashion, and more likely, if you attempt it and do anything irrevocable to the car, you will end up selling the whole shebang at a loss in non-running condition, basically in boxes and piles. That's what usually happens in such cases.

That said, the Chevy small block 400 (they also called the big block 402 a "400" in about 70 & 71 or so) was available from 70 to about 80. Most of them were in larger cars such as Impalas and Monte Carlos, but some were also in trucks and vans. There were only 3 casting #s; 511, 509, and 817. Most of the 511s are from 72 back and were equipped with 4-bolt main caps, but you don't want those (preferentially speaking only - if you can only find that, get it, but if you have a choice, get one of the others) because the casting was kind of lightweight in the main webbing area and they don't take to abuse as well as the others. The 509 and 817 blocks, 73 up, almost all came with 2-bolt caps and the blocks are stronger. The "best" setup is a 2-bolt block with aftermarket splayed 4-bolt caps on it but that's by no means necessary for a street motor. The 511 blocks mostly had 3 freeze plugs down the side, where the others had 2 like any other SBC.



They're not hard to find, but you may or may not be able to find one today, immediately, on demand. You gotta wait for some old vehicle that has one to get scrapped so sometimes there won't be any around. But sooner or later one will show up.

The heads that come on them are GARBAGE. They are all deep 70s smogger trash of the very worst sort. If you find such a motor, spare yourself the trouble of disposing of the useless cast iron, and just leave it behind. All you really want is the block, and if you're going to stay fairly mild (sub 400 HP would be a good dividing line) the crank and rods. The pistons likewise are complete trash.

Incidentally, if you had a 79 Trans Am that said "400" on the hood, most likely it had an Olds motor in it; the 403 specifically. Think back to it: if the oil add place was on a tall stalk in front of the intake, it was an Olds.

RED86Z28

This is nothing more than the old displacemnt arguement and it always ends with go as big as you can. My point is the 305, 307, 327 are capable of decent numbers that most people would be happy with.
At this point I would not rebuild any core because crate power has become so common.

sofakingdom

iTrader: (1)

"Crate" = a wood thing they strap a .... REBUILT CORE .... to, for shipping.

Therefore:
There's no difference between a "crate" motor and any other rebuilt one, except that a "crate" one, you start out with a random core you have no clue what it is, instead of you picking a core somehow and rebuilding THAT EXACT one. All difference ends there. Anybody that can rebuild a motor, can also strap it to a "crate", and that doesn't change the fact that it's a REBUILT motor. The only exceptions of course being NEW (NOT "Targetmaster" or other rebuilt production line rejects) from GM, or the super high $$$$ ones built out of Dart or Motown or whoever aftermarket blocks which are of course brand-new also. Yerbasic eBay motor or any of the rebuilders bandied about on this forum, those motors are just that: REBUILT, whether delivered in a crate or not.

Yes there's something to be said for the "displacement" argument; not least, because it's COMPLETELY IMPOSSIBLE to refute it. Fact of the matter is, no matter what you spend on a small motor, even if it's "satisfactory", if you spend the same $$$ on a larger one, you get MORE. End of story.

Which means, if someone has a fixed pile of $$$$ available to them, they WILL NOT get the best deal from a small motor. Not ANY small motor. Not even a "free" one. Not even a "free" 307 they have rebuilt, as opposed to spending the same $$$ on a "crate" 350. They will get the best possible results from THE LARGEST MOTOR their available cash will fit. The cbic inches are basically free; which if you're going to tell him to buy a "crate" motor, you just yourself refuted the whole 307 argument.

In a word, THERE IS NO UNIVERSE in which rebuilding a 307 is the best way to apportion one's hard-earned $$$$.

Some smaller motors are better than others of similar smallness, all else (heads, cam, $$$, etc.) being equal. For example, among Chevy SBCs, 302 > 307 > 305. Therefore if you're in a class or other sanctioning type arrangement where you have a CID limit, the large bore / short stroke combo FOR A GIVEN CID will win. However, if you are NOT CID limited, then CID will always win, no matter how you get there. Which is to say, the old familiar "NASCAR argument" (if a 400 is so good, then why do they run a 4.155" bore and a 3.25" stroke, instead of a 400? answer: THEY'RE CID LIMITED, they CAN'T run a 400, the rules don't allow it) is FALSE.

Me, I don't know of anyone that I would trust to be as exacting about a rebuild as myself. I would not personally buy a "crate" motor from anybody but a VERY short list of people whom I could trust more than myself. Believe me when I say, that list is VERY SHORT. I rebuild my own.

RED86Z28

Im not in favor of him rebuilding the 307 but I dont like how everyone here has such a negative attitude about other motors. Everything always trails into how they suck because 40 years ago bla bla bla or some other often repeated line. The fact that a 350 would produce more power with the same parts or for the same money is a given and I never disputed but it does not make a 307 the worst thing ever.

What I meant with the word crate was a gm or other decent supplier not some random engine in a box.

sofakingdom

iTrader: (1)

Yeah, sucks, doesn't it?

OTOH, go build a couple of em, WITH YOUR OWN MONEY, and then after you've had a couple of a$$-whippins from people whospent their money more wisely, come back and let us know why those of us who WERE THERE AT THE TIME shouldn't try to help others avoid making the same mistakes. I can assure you, NOTHING has changed about them in the last 40 years. Sitting in junkyards and garages hasn't improved them ONE BIT.

And you're right, the Chevy 307 isn't the worst thing ever. As stated up there, the 305 is arguably worse, and then of course there's even more stellar wonders of automotive excellence like the 267, 6-cyls in general, and so on. So yeah it might suck, but it's not the total bottom of the barrel. Just, close enough that there's a HUGE diference between spending say $2000 on a 307, and comparing that to taking the same $2000 and buying a 350 core and spending the rest on it; and it DOESN'T favor the 307.

RED86Z28

I and can assure you plenty has changed in 40 years. The options you have for the heads now make a huge difference. My point is not even about what would make more power its simply that the 307 shortblock is a viable option depending on what you want.
I don't care about whose car is faster at this point in my life. Mid 300s would make me happy.

tylercamaro

iTrader: (1)

my old t/a was definitely a pontiac motor, and now that i think of it everything was backwards, but the fact that the 700 wont line up to it nicely sorta puts a damper on things, so the chevy is the way to go im assuming, its just finding one thatll be the challenge

sofakingdom

iTrader: (1)

Shouldn't be too hard... they're out there. Just be patient.

tylercamaro

iTrader: (1)

so with a lower budget build how much could i possibly make, and would i think more than likely my trans would stand up to it but im not too sure