Rebuilding my '86 307. Advice?

[442 Owner]

Hi everybody! I'm new to the forum here and i was looking for any tips on rebuilding my stock 307 engine. We are replacing the stock intack with a high-rise intake and the lifters with higher performance lifters. Also, we are scrapping all of the junk in the engine (the emissions pump and wiring) to clear the engine and hopefully get more horses out of the engine. I have read several articles that say rebuilding a 307 is a waste of time, any opinions?

 

[-83MONTESS-]

If your looking for big power (or power for that matter ) I would start with a 350 (OLDS of course!). You could open it up a little with a nice exhaust/intake combo. A good carb, nice heads and all that fun stuff too. But its like trying to polish a turd. You would probly be farther ahead (and I know this is gonna start a board wide war) to find yourself a 350 or bigger. Who knows you might find a 455 Good luck on it.

 

[442 Owner]

If your looking for big power (or power for that matter ) I would start with a 350 (OLDS of course!). You could open it up a little with a nice exhaust/intake combo. A good carb, nice heads and all that fun stuff too. But its like trying to polish a turd. You would probly be farther ahead (and I know this is gonna start a board wide war) to find yourself a 350 or bigger. Who knows you might find a 455 Good luck on it.

I have access to get a 455 because my dad is an old friend with someone who drag races his 78 olds cutlass and has an extra motor. however, I do not have the money to pay for it or the gas it will chug. at least the 307 is a little easier on my wallet.

 

[beermonkey9417]

well the problem with the olds 307 is that there arent many aftermarket parts for it redily available. but if ya take yer time and do some reading you can get some good #'s out of yer boat anchor.i have a sbc 307 that i rebuilt and its making a guestamit of ~300hp. so just keep at it. try and find intake, heads and exhaust thatll fit correct. and while yer in there you can upgrade to a decent cam and lifters ad even rockers.

 

[dogsht]

Stick that numbers matching vin 9 307 under the garage bench to keep your 442s resale value & marketability to someone who might want to pay top dollar for a concors type restoration. Horsepower is in the heads and the
307s had poor heads. It's not easy to get good power out of a 307. Torque which you want in a heavy street car comes from cubes. Lastly you can rebuild or build up a 350 or 403 for the same money. Both will automatically have more torque and are easier to get HP out of and both a direct bolt in as they are externally the same dimension so everything bolts right up looks the same.

Edit, what kind of mileage you getting now? I got 18 hwy with my regular 307 & 2.56 gears. I have gotten 17.0 & 16.8 once on a hwy trip with my 442 with a 509 in it. You can check it out in my pics. WWW.robertpowersmotorsports.com. Bob got as good as 15 hwy and ran a best of 12.3 at 110 mph with a 455 overdrive, working lockup, qjet. Dwight whos cardomain address I don't have did 12.0s & a little better on mileage. More pumping losses from a larger engine is only part of the mileage thing.

 

[-83MONTESS-]

I guess I shoulda asked what your plans for it were. How much hp and torque you shooting for? And what type of driving? Theres no doubt you can build a 307 up. Its just gonna take a helluva lot more $$$ than say a 350+.

 

[G-Body_Vet]

What dogshit ^^^^^^^^^^^^^^ said! Just keep the OD trans in the car and it won't be as bad as you think.

 

[chiguy109]

whats up fellas i just happen to have a 403 with 400 trans still hooked to it the motor was rebuilt bout two years ago when i say rebuilt i mean the block was dipped, cleaned and painted the crank was polished new pistons,p-rings cleaned and reused p-rods new oil pump, timing chain 1 step up from stock cam heads were cleaned checked and had a valve job i did the motor for a customer along with lambo doors and sun roof then he came back with a chevy 350&700r4 bout a year later so i did the swap and had the motor then he crashed the car brought it back for a lil body work and paint and never came so i pulled the 350&700r4 back out junked the 79 2 1/2 and the 403 is still sitting in the garage complete -the intake sold it already its been for sale but every1 try to low ball me but i kno what i got not asking much $700 firm if intersted give me a jingle 773-971-6987

 

[442 Owner]

we are shooting for around 300hp, which should not be too terrible to reach. I will post pics as soon as we get started on it.

 

[dogsht]

Did you know that will take spray or a complete ground up rebuild with new pistons & rods to both work with new ported heads and to get the compression necessary to work well with the cam that would be required to make 300hp from a 307.

The thing is this would cost more than rebuilding a 350/403/455 to make the HP plus giving you more torque and being a more docile reliable engine. In fact some stock early 455s made that. 220 HP is a lot more likely out of well built but economically built 307. I am not picking on the 307 it was a reliable torque off idle motor just trying to share about what it takes to hit your goals with one.