I have a 307 chevy engine in my 1970 Buick GS.   What are some good mods for it.   

How in the heck did that transplant happen?  You could always do the usual... cam, intake, exhaust, etc.  But, realize that a 307 has inherent restrictions.  Particularly in the bore size, which will restrict your cylinder head options.

The money to build a 307 could likely be better spent on a 350sbc, or better yet install a Buford in that thing. 

First,I'm sorry to hear someone neutered your GS.I think your money would be better spent leaving the 307 in the car until you can build a worthy 350 for it then swap the engines.

                                         tndscrt

How do you feel about how it runs now? I say stick with the 307 all the otther people say scrap it but if you know the state of this engine , compression test  oil preasure hot etc and it is good  just dont go radical on the cam and heads that  flow too much for it it will respond like any otther small block plus with 307 gas milaGE.

I am not trying to insult anyones inteligents but are you sure it is not a olds 307? I mean that would bolt up to the 455  transmission. If the buick went south wouldent it have ben easier to use the same trans? I know you are gooing to tell me you know a small block chevy from a olds right? Well some time ago I couldent.  

bore ,,,,,,,,,,,,,,,040 over

3863151 cam stock high performance

rebuild port&polish your heads or buy new ones

headers, intake, carb, & HEI distributor

mine puts over 240 hp to the rear wheels (dynoed)

2500  stall (wish I could have a 3000  & 3.73 with new eaton ,broke stock posi unit going 1st  to 2nd  WFO

All this in stock 71 camaro, 313 ci ,trubo 350

have fun, quit smiling , cut a good light      bye bye

You ruined your rear posi.I used to turn u joints into peincle tips every 6 months.I bought the truck with a strip kit in my th350.He told me never to go past 5500 from 2nd to drive.One day I went to 6k and when it hit drive that was it.After putting another th350 in it afew weeks later I went to drain the converter of the old trans.Something went clunk into the bucket.What I pulled out was chunks of the splines that drove the front hub in the trans.That was ok because even the stock trans i replaced it with barked second.I kept the old trand and a few years later I had the driveshaft in my 83 malibu cut and balanced so I could put the strip kit 350 trans in it.(older trucks and large cars ran a long tail shaft) It worked fine and then I could go sideways 1-2 and slam 3rd pretty hard.Anyone ever do this to the splines on a stock converter?It looked really porus cast iron that was machined from cast iron.Do aftermarket converters have steel splined shafts?  

im carfreak sblakely pain in a$$ son you said you have an 83 malibu im hoping for some advise on building one because on 7/11 i took my first trophy in my dad car the bet was i can race it till i took my first trophy if i new that i would get my trophy on my first night i would of lost on prupose now i have to build my own car i have 78 malibu and my dad has an old 396ci laying around i need a good drivetrain do you have any suggestions? the 396ci is a two bolt main im still inhigh school so are used part ok?

                                                                     thanks carfreak 

Used parts are fine if they are in good condition.If the 396 is in questionable condition I would at least do a rering and new bearings on it .The cam is another story it needs to match or work with everything else or you will never see the full potential of the car and you will not get what you want out of the car.As for the 2 bolt main I am pretty sure there are no factory 4 bolt main big blocks.For the block to fail through the main cap I think you would have to be in the 600 horsepower range.I would pay more attention to yhe rods and rod bolts.The week points of tour car are:rear end,front springs,stock transmission.You should start with making sure the brakes are in good condition.The steering and suspension is not worn.Do the SAFETY issues first .If you work on making more power first and ignore the otther things you may never make it past 18 years old.I dont mean a million dollares in trick rotors and  polyurethane bushings unless you can afford it.Just make a list of everything you find that is worn out and go to the local auto parts store and get some prices.The frames on the mid sized gm cars tend to rust out  after the drivers side rear wheel to the bumper.Mine was good it was a police car and was undercoated from the factory.Any more questions just ask.I cant cover everything here and too much imformation is intimidating.Print this If you can that way u dont get it mixed up in your head or foregert it like I do sometimes.  

gearman thank you  

My first impression is that it is an olds 307, but you know your car more than I do.  If it is a Chevy 307 its not a bad thing either.  The Chevy 307 is the little brother to the 327.  It is a high reving engine (short stroke large bore).  Some will mistake it for a dog like the 305 (long stroke small bore) but that is not the case.

A slightly larger cam and higher flowing heads will give it very respectable hp at high rpms.  Since this is a little bit too much air and fuel for the 307 at low rpms, a stall converter may be required.

When on a budget, keep the 307.  Some people gave me alot of crap about rebuilding a 307 for my '77 shortbox chevy, but they shut up really fast when I out ran their 350's.

"The Chevy 307 is the little brother to the 327.  It is a high reving engine (short stroke large bore)." 

Some guys will disagree with you, and claim the 302 is the 327's lil bro while the 307 is the big bro to the 283.

While the 307 and 327 share a common stroke, they don't share a common bore.  The bore size (3.875") of the 307 limits its cylinder head options. 

Don't get me wrong, I'm not throwing rocks at the 307.  They can be built into a respectable street runner.  Yet, the fact is they are inferior to their cousin 302/327/350.  Dollar for dollar, or cid for cid, any one of those will smoke a 307.

Peace.

When on a budget, keep the 307.  Some people gave me alot of crap about rebuilding a 307

for my '77 shortbox chevy, but they shut up really fast when I out ran their 350's.I LOVE  THE STORY ABOUT BEATING THE 350s.I once outran a 79 monte carlo with a 267.I had a 82 half ton with the 250 stright six  and a 4 speed od and ridiclous tall gears.He was so pissed about the stright six.Hell  my truck may of ran a 21 second quarter.

Think of the 307 as a torquey 302. 305 heads and a tpi from the wrecking yard would wake it up a lot. I couldn't see if you wantted a high rpm screamer or just a tire roaster. the tpi in all the desktop dyno modeling I have done is just not efficient after 5k. On the other hand that gives you a solid 3.5k rpm (1500- 5000) to work with. Also do not overlook the benifits of todays hyd roller cams.  This is the single best Mod you could make in my opinion.

Heads, headers, and tpi from a 305 car. Plus A comp Cams XR252hr ( or XR258hr ). this engine would make nice solid torque.

for higher rpm work think about the holley street ram system.

Good luck

"Think of the 307 as a torquey 302."

LOL.  The two are in different leagues.