Chevy 307 V8

[edgarcampos323]

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?

[silicon212]

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.

[MrPbody]

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

[edgarcampos323]

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

[randy78]

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

[Blue Bowtie]

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.

[silicon212]

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.

[Blue Bowtie]

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.

[comp]

Originally Posted by silicon212

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

[silicon212]

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

[MT-2500]

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

[edgarcampos323]

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

[silicon212]

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.

[comp]

so what did you do ???

[luxeryvic]

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