hi, im beermonkey form chicago burbs. i have a 307 sbc from a 71 camaro, but, its in a 78 el camino. i have the heads, headers, intake, carb, and distributer off. the heads that were on there were stock and i've taken them in to the shop, and one is cracked and the other needs work. i wanna get better than 200 stock hp. the parts i do have for the engine are an hei distributer, performer intake and hedman shorty headers. i just need some help with heads. ive heard about 882 and 417 or 416 and vortec. i wanna know what will give me better hp #'s and not TOO high compression with 1.6 roller rockers. any tips?

 

i would buy a set of vortec heads off a truck with the 5.7 vortec motor and clean them up a bit..my dad is est. my 307 to make about 350-375hp with stock crank and rods..if you need the motor to be bored and honed i will guess about 375hp...

the only big deference between yours and mine is im going to run a TPI on mine..

 

How can you had Stock HP and have more HP then originally came with the car? The motor came with 140hp stock. The most you can get from it is 140 stock HP. To get to 200HP you will have to make it not stock.

The 307 is a denuted 327. There is plenty of info around on building 327's. The big things they changed was compression, cam, and heads. If you want a decent motor you need to address all these areas.

 

actually the motor is a 283 block with a 327 crank. and a de tuned 327 is a 302 i think... but yeah the motor came 200 hp stock with all the smog stuff but i dont have that. i was hearin that 417 or 416, whatever, are over looked heads. i want some heads that flow good and have like 9.5 compression. the motor is carburated and its 650 cfm and i was told thats too much, i need like a 600 cfm. i did find one for 199 bucks. like i said earlier i wanna put some 1.6 roller rockers, and MAYBE a mildly larger cam. so what else i need to know, cuz i have no idea. i gotta find the casting #'s so you guys have a better idea what i got.

 

heres the casting # 3927185 1968-76 307-327-350 70cc chambers

 

The 70 307 lists at 200hp the 71 lists at 140hp@4400RPMs. Also calling one of the most powerful small blocks ever built de tuned 327? I am sure that is just choice of words. All the short stroke motor need RPMs to make real power. A motor built buy pros to factory spec (stock) for a 302 can dyno at 490hp at 6500 RPMs.

You will need to change the cam. Right now the stock Cam would have a long duration. Your 1.6 rockers would make that worse. It will not work well at higher RPMs. Your high flow head will only help at high RPMs. Infact the High flow heads could slow down the air speed and cause a drop in HP due to the low CFM your motor needs. The best way to build a motor is to figure where you want the power, pick a RPM range and get the right gears and tire size to put you car right where you want to be. Once you know the RPM range give that along with your motor specs to tech support at the Cam manufacture. They will tell you the best off the shelf fit for what you want.

 

I would say you have your work cut out for you. Heads, cam, intake, and pistons are going to be needed to get any real power out of it. The rods and crank should be strong enough to hold a good bit of power.

Long story short get rid of every thing but the block, crank, and maybe rods. Every thing else needs to go. Or grab a ZZ4 and call it a day

 

Bingo! we have a winner.

 

id love a zz4! anyone got a spare 3g's? i dont wanna change out the pistons for this motor, ive already took off the whole top end off. right now im at the point where i just wanna drive the damn thing. a lil better power would be nice untill i save up for a 350. but id like to drive it sooner than later. like last week well im off to search on craigslist...

 

Well you can't make a silk purse out of a sows ear,a 307 is what it is and not changing pistons you can't expect much out of it.
Just drive it and save your money toward that 350 you want is my 2cts,every penny spent on that boat anchor 307 is a penny you could have put away for a 350 build or crate.
You might get lucky and find a wrecked donor car or truck with a good 350 in it for a song,it's a good way to upgrade on the cheap.