Chevy 307 V8

I have a 1969 307 chevy V8 engine, along with the tranny it came with. I was wondering if there was any way to get at least 300 - 350 HP from this engine. i'm aware that its got 200 HP and 300 ft lbs of torque. Ive had people try to discourage me from building up this engine telling me that it is a piece aof crap and that it has nothing on a 350, but i also hear of some guys that have gotten at least 400 HP from it, so i decided to try something different. Ive also heard that there isnt enough all thickness to bore the block, any suggestions on how to give this engine a descent kick??? is it worth it?

A 307 is basically a stroked 283 engine (327 crank). Power mods are similar to the 305. It can be done, but it will cost more than a 350 would.

Agreed. ANY small block Chevy is capable of making significant poewr, but there are cases of "diminishing returns". The bore size is small enough to inhibit head flow with the "good" (1.94 intakes) heads. 305 "HO" heads can really wake it up, though.

If you simply want more power, the 350 is the least expensive and least "painful" way to do it. If you want to "prove a point", absolutely, 307 is just as capable of making 400 horsepower as any other small block. Just bring a wheelbarrel full of money...(:-

Jim

Thanks for the suggestions and info :)
I plan to put this 307 in my 74 Nova replacing its inline 6

whatever you do to it can be transferred to a larger displacement sbc engine later on

other than boring it, etc

you could for now mill the heads or put on a dirt common set of the 80-86 years car and truck 4416 casting 305 heads,

port them yourself a bit,
polish the exhausts and smooth the runners to help it flow a little better, put 1.94 intake valves in it altohugh thats getting costly to have done these days, the valves are cheap though


but its really pointless for the most part with such a small bore engine as this

is it s truck hi-torque 307 or a turbo fire car one ?

theres a huge difference between the truck and car engines back thenthe truck ones were high torque output at a very low RPM whereas the car ones were more HP instead of torque

200 is higher than the truck ones

307 was from 68 to 73

327 and 307 are the same stroke crank yes

Back when they were first made (and I can still remember back then) the 307 was generally regarded as a good marine engine. Thankfully, they were not made for very long, and not many people actually used them as an anchor, thus polluting more waterways.

In other words, I'd lean very hard toward finding a later model (1987-later) 350 roller block and start from there. The later heads are likely to already be much better, the roller cam is going to be a huge advantage, and the 350 will net about the same mileage as the 307 in the same weight installation. The transmission will work with the 350 just the same.

I don't doubt that a well-built 307 could make 400 BHP, since a well-built 350 (well, actually a 358) can make 750 HP without any kind of power adder. If you question that, just watch your TV this weekend for NASCAR races and see all the 358-inch engines making 750+ HP with only a carburetor. Chevy was there first.

Hey Blue Bowtie, they're up to 800BHP from those engines now.

Still, using a single Holley 750SCFM carb and Mallory/MSD ignition.

Still, with 358 CID (a NASCAR limit).

The same engines with a 15/16" restrictor plate under the carb make over 500.

I'm really living in the past. I recall a 7/8" restrictor. When did they bump it up? That always gives me a tickle, especially when I read hundreds of posts in various forums (fora?) that a bigger throttle body makes more power. The TPI and LT1/4 guys really provide the humor, since the common misconception is that a "tiny" factory 48mm TB will only allow X horsepower, but the factory uses that same 48mm TB on the RamJet 502 and makes 500+ HP and 500 ft/lb. When faced with that reality, the replies usually fall off to nothing while everyone goes back to study Fluid Dynamics 101.

Hey Blue Bowtie, they're up to 800BHP from those engines now.

Still, using a single Holley 750SCFM carb and Mallory/MSD ignition.

Still, with 358 CID (a NASCAR limit).

The same engines with a 15/16" restrictor plate under the carb make over 500.

in the past week they have been talking about Over 850hp

I guess I've been living in the past, too!

Talk to some of the people in racing and performance engine building.
I would go for a 4 bolt main bearing block.
Chev also has several other big blocks to.
But remember HP is not cheap Big HP = Big bucks.
MT

s it s truck hi-torque 307 or a turbo fire car one ?


It is a turbo fire car engine, believe it came out of an el camino

There are no 4-bolt 307 blocks, and the castings I've seen don't have enough material in the webs to install 4-bolt caps on them.

so what did you do ???

this is just an idea ive been thinkin about to do to a 305 someday, but could you put a 383 or 400 crank in with a bit of maching and make it a stroker?

it would increase the cubes and with some porting and machine work on the heads it would easily be up there with the 350

this is just an idea ive been thinkin about doin to a 305 block that needs boring ( if it works ill do it when i get the money ) but couldnt you put a 383 or 400sbc crank in with a bit of machining to the block to make it a stroker?

sorry i hit the back button and thought i had to write it out again . . . guess not

You can stroke a 305 - using a 400 crank (3.75" stroke) on a 3.766" bore (.030 oversize 305) will yield 334 cubic inches or 5.5 liters. I don't know if they're still available (I don't see why not), but there are/were kits on the market for this purpose. They came with the prepared crank, rods and pistons. You will also need to use a 400 externally balanced flexplate and harmonic balancer - same as with the 377/383 stroker.

Prep the crank as you would for a 350 stroker, and make certain you have the rotating assembly balanced afterward (if you want it to live beyond break-in).

im new to the engine building thing, how do prep a crank for a 350 stroker?

You have a lot to learn, but it's fun and rewarding once you breathe life into something you put together.

The 400 crank comes with a 2.65" main journal; the only small block to do so. The rest come with a 2.45" main journal as of 1968, or 1967 on the 350.

In order to make the 400 crank fit the other blocks, you need to have it machined so the main journals are 2.45". You also need to notch the block at the pan rails for connecting rod clearance with 5.7" rods. You then have the rotating assembly professionally balanced. Many times, you will also need to run a cam with a smaller base circle (shaft and lobe diameter) in order to prevent rod-to-cam interference.

i know i havew alot to learn, im 16 and yes, im biulding a 305 now with just a cam, headers and a q-jet and im havin fun, cant wait to put it in to my 77 monte

it thought some machining would be needed and i knew everything has to be balanced, but how big of cam (lift )can you go to

i know i havew alot to learn, im 16 and yes, im biulding a 305 now with just a cam, headers and a q-jet and im havin fun, cant wait to put it in to my 77 monte

it thought some machining would be needed and i knew everything has to be balanced, but how big of cam (lift )can you go to
TRW L-82 replacement isn't to bad and about as cheap as it gets

so how big of a cam can you use, without having to worry about interference?

Generally, if you're using the standard base circle, a cam with .480 lift (1.5:1 rockers) is about as big as you "dare". Using Eagle H-beam rods (or others with a similar profile) can increase that as the rod doesn't have the "meat" in the same areas as the stock rods. We have success grinding a bit of the rod bolt "head" on the insde bolt off, allowing a slightly higher lift (no rod bolt failures due to this). With the smaller base circle, I've used cams with up to .600" lift with no interference. Most good cam grinders supply a small block cam on the smaller base circle for this purpose. Longer pushrods are necessary with the small base circle, to maintain proper rocker arm geometry.

Stroking the 305 will yield a very "torquey" engine, but don't look for it to be a "giant killer". Due to ports and valve sizes, upper RPM power will be lacking.

Jim

what do u mean by a torquey engine? and why?

also if i ever do this i plan on using an edelbrock performer intake (ive heard 305s like these ) and a modifided q-jet

what cam would u guys recommend, i want high lift but short duration to keep some of the cylinder pressure, any suggestions?

also, i would put this engine into a drag car, i was thinkin an 80's compact, what torque converter should i use and would a TH350 be good enough or should i go with a TH400?

what do u mean by a torquey engine? and why?
He means a relatively low-revving engine that builds relatively more power at lower engine revs at the expense of high rev power. This is generally not as desireable as a high revving engine (for a lighter car) but is okay if you set up the gearing for it.
also if i ever do this i plan on using an edelbrock performer intake (ive heard 305s like these ) and a modifided q-jet

what cam would u guys recommend, i want high lift but short duration to keep some of the cylinder pressure, any suggestions?

also, i would put this engine into a drag car, i was thinkin an 80's compact, what torque converter should i use and would a TH350 be good enough or should i go with a TH400?
Well, for a lighter car, (less than about 2800 lbs, a 2 speed Powerglide trans, when properly set up) is faster than a TH350 or 400. In heavier cars, a TH350 is faster.

Otherwise, the TH350 is faster than a TH400, so only use a 400 when you are sure the engine is so strong it will break a 400.

However, as was mentioned twice in earlier posts, if you are getting serious about the build - up, buy a 350 and build that. You can sell the 305 as-is to help finance the project.

The 350, even the older non-roller (pre-'87) 350's are a much better platform to build for many reasons, including better heads, bigger valves, more available parts and more displacement.
Building a 305 as a race/performance engine is like starting a boxing career when you only have one arm. It's too difficult to be worth it.

For the dollars you are proposing to spend, throw a couple of hundred at a good usable 350 core, rebuild it and go from there. You will be thankful in the long run!

everyone has 350, i heard of somepeople that have preety strong 334 strokers and i think it would be fun

how would i set up the gearing, do u mean the rear end ratio? what ratio would u recommend?

also what so u mean when u say properly set up 2 speed Powerglide tranny?
what should i use for a torque converter or a cam?

everyone has 350, i heard of somepeople that have preety strong 334 strokers and i think it would be fun

how would i set up the gearing, do u mean the rear end ratio? what ratio would u recommend?

also what so u mean when u say properly set up 2 speed Powerglide tranny?
what should i use for a torque converter or a cam?

When building engines or setting up rear ends or selecting a transmission.
You need to decide what you are going to use them for.

Talk to the people that build them and have plenty of expeririance.

And have plenty of cash on hand before you start.
Good Luck
MT

When building engines or setting up rear ends or selecting a transmission.
You need to decide what you are going to use them for.

Talk to the people that build them and have plenty of expeririance.

And have plenty of cash on hand before you start.
Good Luck
MT

Best advice all day!

everyone has 350,
I don't mean to be a pain in the ass, but why do you think that is?

Because it's the best choice for most situations, including, IMHO, yours. :)

I can understand the desire to build something different, after all, I did built a mondo '81 Fleetwood with an Olds 455.

For a first car, I suggest go with the tried and true 350. Your car itself is different enough to attract attention; you just need a 350 because imho it will haul it down the road with the most speed for the least money. :wink: