chevy 307 why do they suck?

[marq]

please explain someone why 307 engines are garbage?....................Marq

[Unkl Ian]

I think that was a 70s smogger motor.
Small bore,long stroke,low compression,small carb,small cam.

[RileyRacing]

they aren't any worse than a 265 or 283. Small valves, short stroke... I got one out of a Chevelle, I will use it someday.

It's just cheaper (or how bout more Cost Effective) to build a 350, more bang for the buck, ya know!

Jay

[choprods]

WHAT YA GOT IS A 283 BLOCK WITH A SMALL JOURNAL 327 CRANKSHAFT[stroke].
they really are not as bad as all that!
change the camshaft and lifters[BOTH A weak point] use a 350 horsepower 327" cam- ...make sure to get[anti pump up]lifters.slap on a 500 CFM carb and drive the living shit out of that motor!

[burger]

A 307 is a 327 crank put into a 283 block. What you get is a poor bore-to-stroke ratio and relatively small displacement. You end up with the displacement of a smaller engine with the rev limits of a larger motor.

A better combination is the 283 crank in a 327 block. That combination gets you a 302, as found in 67-69 Camaros. There, you get the rev capabilites of the smaller motor with more displacement.

Long winded, eh?

Ed

PS- It's not a bad motor... it gets bashed because there are better SBC variants that offer more performance for less money.

[Tudor]

Edmurder, I have a 283 motor - is there anything good to do to that - I thought I could build the 302 and have a high winder - but it sound like I have the reverse of what I need!
shit

[burger]

Tudor,

If it has a small journal crank, you can take that out and put it into a 327 block.

Don't bag the 283 just yet though! I've got one in my '31 Coupe. I haven't fired it up yet, but I'm sure it'll be more than enough motor for a light car. Part are more expensive than those for a 350, but they're still a lot cheaper than flathead or Olds parts.

For the next engine, I'm going for the most performance per dollar. So far I'm planning to use an 87-up 350 block (roller cam) with aftermarket heads and a stroker crank.

Ed

[MercMan1951]

ROCKETJ2--------------------------------------------------

You know and I know that's Joe's 307 hauled ass.

I had heard the rumors about 307's...and had never given them much thought; until a friend came across one and mildly built it:

For those of you that don't know the story, we had a buddy in H/S that got a '72 Chevelle plain-jane special for a steal. It wasn't even a Malibu. It was what they called a "Chevelle 300 Hardtop." No frills, No air. AM radio, bench seat, NO chrome trim, NO vynil top, standard everything except power steering.BRONZE color with a black interior. A 2-door, but one notch up the chapness scale from a 2 door POST car...actually, quite rare now-a-days...

Anyways, when he got it it was all stock. 50,000 some odd miles on the clock. The original owner had clocked the mileage with every fill up of gas. A well-maintained, but aged, Michigan car. Had a TH350, open 10 bolt rear. 307. Our buddy added an Edelbrock intake, carb & cam w/ lifters (am I right Jay?) to replace the 2BBL, and a set of headers from Heddman, with duals.

That car would pin you in your seat on acceleration, and I couldn't believe it. Stock rear end (open), stock brakes, stock everything. No Air. Loud as hell when the pedal was mashed. If you told me what had been done to the engine, and then sat me in the driver's seat, and I didn't know our friend, I would have told you that for the power the car had, he must have done something to it you were't telling me about. Maybe it was due to a low-mileage engine that had never been apart...NAW....

He beat the shit out of it for a while as his everyday driver, until it had no brakes, then parked it and forgot about it for a few months. He sold it to me for parts for my '71 SS Chevelle. I bought it for $200...all I wanted was the fenders (they we NOS GM)...and I sold the rest to RocketJ2...who scrapped it after deciding it wasn't worth restoring due to rot in the ass-end. He kept the motor, and dis-assembled it. Scrapped thew rest....

It was a motor that pulled like a 350, but wasn't. That's my experience with 307's. I wouldn't hesitate NOW to build one. They aren't as bad as they're rep has them to be.

[Bigcheese327]

[ QUOTE ]

If it has a small journal crank, you can take that out and put it into a 327 block.


[/ QUOTE ]

They're large-journal motors. Yank the crank, stick it in a 350 block with 327 pistons and *wham-o* instant 327.

Everyone knows 327s are cooler than 350s, any day.

[zman]

There are large journal 307's that were in trucks. You can take the cranks out of those and put it in a 350 block for a large journal 327. A truck 307 is not so bad, made more for low end torque. If it runs use it. No problem...

[tomslik]

uh, ALL 307's were large journal
truck 327s were steel large journal, most cars were too.
btw, this only applies to 68-69 vintage engines

[RileyRacing]

Kev's right... that Chevelle was bad ass. that's why I kept the engine. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

Someday, in a light car, it'll be bad ass again.

Jay

[buckethead]

I had a 307 in a '68 pickup back in high school. Stock 307 with th400 and 3.73 gears. I seldom lost a race in it but the fuel economy really sucked. It had a rochester 2 brl. and got 9 mpg. I changed to a Holley 4 brl it ran allot better and still got 9 mpg. I put about 100 k miles on that motor with no problems ever. I rebuilt it later and put 300 hp heads on it and bored it .060 with stock cam it ran allot better yet but still only 9 mpg. Eccept for the gas milage on the 307 I had no problems with the motor.

[DrJ]

The 305 is the one that really sucks

[Fat Hack]

Ha Ha, DrJ!

I think you meant the 267 maybe???

A small block Chevy is a small block Chevy...unless it's a 400...then it's a big block in disguise!

http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

[DrJ]

[ QUOTE ]
Ha Ha, DrJ!

I think you meant the 267 maybe???

A small block Chevy is a small block Chevy...unless it's a 400...then it's a big block in disguise!

http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif


[/ QUOTE ]

Yes the 267 sucks and the 265 sucks and the 262 sucks all because they won't take 2.02" valves ad with 1.94" valves the cylinder walls shroud the valve and restrict the amount of cam lift you can use, but I was only citing the 305 because it's numerically close to a 307 but an entirely different engine sufferning even more from the small bore long stroke problem.

[uncleAud]

http://www.goingfaster.com/spo/praisetbi.html

[redmeat]

<font color="red"> Cause it's a CHEBBIE motor!

R E D M E A T </font>

[tomslik]

funny, he never said(or knew) WHY chevy built a 302....

trans am had a 5 liter engine size rule back then.....


hey, btw, as much as i don't care for 305's, i did end up with a 79 monte with a 305/4bbl/350 turbo.
anybody know hp+torque specs on it?

[rodrelic]

My dad (carpenter) had a '64 C10 for about 3 years until it rotted in half, 283 2 barrel collum shift. That thing went like a big ass bird, he loved that truck. In '71 he bought his first new one, a C10, and he chose the 307. What a pig, I think the 292 in the old 2 ton had more snap than that 307. He had a 350 in the new '78 but it wasn't as hot as the 283. I will say as the 307 got older and looser and lost the smog stuff it was better, but still a disappointment.

[porknbeaner]

Bad bore to stroke ratio.
They don't suck they are what they are.
Anything can be built, just some things easier than others.

[Dakota]

307s are 350s with a smaller bore, you can punch a 307 .125 i believe and get a standard bore 350... They are great when you are having a hard time finding a goond candidate for a new 350. ALSO, 307s usually have a higher nickel content in the block making them alot stronger than most of the newer lightweight blocks....

[porknbeaner]

[ QUOTE ]
hey, btw, as much as i don't care for 305's, i did end up with a 79 monte with a 305/4bbl/350 turbo.
anybody know hp+torque specs on it?



[/ QUOTE ]
tomslik
go to http://www.mortec.com/ and dig around. there's a world of Chebby info there. I know, I know, shameless spam.

BTW upgrade the cam and work the heads on the 307, put it in a lite body and leave it a 307. It probably won't break and land speed records, but it will be a respectable ride.

[marq]

Just like to say a thanks for the replies guys i am now using a 350 sbc until i can get the 392 in,which may be a couple of years yet .............Marq

[Rocky]

I bought a 72 nova in 1980. Had the factory 307, 2 barrel, single exhaust with a factory muncie 4 speed. What a pooch! It had a pretty nice body so I felt it deserved a little engine work. I replaced the cam with a 350 hp cam, stock Q-jet and changed the exhaust to headers and dual exhaust....just your basic sbc mods for the time.
I drove it to Oregon and back one summer, a 4000 mile trip. The car got 18 MPG if I kept my foot out of it and had all the power I needed. Granted, it wasn't a 350 hp 350 but it was respectable.
It was also one of the few cars in our parking lot that would start at 20-25 below zero. I eventually tore up first gear after changing to a killer Zoom clutch. When the body began to rot I sold it for 3 times what I had in it and the guy who bought it couldn't believe it had a 307 in it after driving it.
These engines had a really shitty cam and that is compounded ever further by these things having lobe-flattening problems. When I changed my 70,000 mile cam, it had worn about 5 lobes round. No wonder it was a pooch.