so my 307 is not long for this earth

[dan2286]

I've got an idea that maybe hasn't been posted yet, although I didn't entirely read everyone elses posts. Can you keep the original 307 block and heads, but put in a crank with a longer throw along with matching rods and pistons that may get you a 326-340 size displacement? I'm not familiar with Olds engines but I know some Pontiac guys will put a 455 crank into a 400 to yield a 428 or something similar. Also just like the 350 SBC guys that come up with 377 and 383 etc. Possibly there's a kit for you to upgrade the 307 and drop it right back in there with a lot of original parts (and matching numbers possibly).

JOE

I am almost positive all small block Olds use the same crank, so it would have to be custom or aftermarket and will take a lot of money for not that big of a gain.

 

[gto78]

I don't know Oldsmobile, but is the 403 a different block? Just thinking it's so much bigger displacement that its gotta have a longer throw crank- but again probably a bigger block and not interchangeable.

 

[dan2286]

I don't know Oldsmobile, but is the 403 a different block? Just thinking it's so much bigger displacement that its gotta have a longer throw crank- but again probably a bigger block and not interchangeable.

It is the exact same size externally. I think there is some differences in the cooling passages. They do have some pretty thin cylinder walls and that limits what they can be bored to. They do use the same crank.

 

[olds307 and 403]

Olds small block uses bigger bores for bigger displacement. The 403 has a huge siamese 4.351 bore. All the blocks are different, you can't bore a 260 or 307 to a 350 bore. The early 350 can go .100 over and the 260 and 307 can go even more. The 403 is like the sbc 400, you can only go about.040 safely. You can off set grind the stock crank and run small journal sbc rods(3.5" stroke) or honda rod journal(3.62" stroke). The 350 can use sbc 400 piston but the other motors need custom pistons.

 

[87SS383]

I've seen some guys do some insane things with a 350 rocket. and a pro charger is only around $2000 on top of that.

 

[86Olds442]

So I finally have an update. Looks as if the 307 will make it after all. I had the rear main seal replaced, and had a new oil pump put in at the same time. I did not want to drop my oil pan in my driveway with no garage, so I had my shop do this work. I explained my oil pressure trouble to them, and asked that they check it out thoroughly once the oil pan was off and they were replacing the rear main. He told me that the bearings looked good, as did the rest of the bottom end. We opted to just replace the oil pump with a stock unit, as opposed to a high pressure one, based on these findings. Well I finally got the trans back in it today and tested her out. All looks good! A little over 50 psi full cold at idle, and holding in the 20-25 psi range full hot and in gear idling. This is a big improvement! This is using my stock gauge, which has actually been proven to be quite accurate with a mechanical gauge. Who knew that GM could actually make an accurate gauge? LOL I guess the moral is to never give up.

 

[jae]

Good deal!!

 

[86_olds]

So I finally have an update. Looks as if the 307 will make it after all. I had the rear main seal replaced, and had a new oil pump put in at the same time. I did not want to drop my oil pan in my driveway with no garage, so I had my shop do this work. I explained my oil pressure trouble to them, and asked that they check it out thoroughly once the oil pan was off and they were replacing the rear main. He told me that the bearings looked good, as did the rest of the bottom end. We opted to just replace the oil pump with a stock unit, as opposed to a high pressure one, based on these findings. Well I finally got the trans back in it today and tested her out. All looks good! A little over 50 psi full cold at idle, and holding in the 20-25 psi range full hot and in gear idling. This is a big improvement! This is using my stock gauge, which has actually been proven to be quite accurate with a mechanical gauge. Who knew that GM could actually make an accurate gauge? LOL I guess the moral is to never give up.

how much did the shop charge u to pull the oil pan out i need a new gasket

 

[86Olds442]

So I finally have an update. Looks as if the 307 will make it after all. I had the rear main seal replaced, and had a new oil pump put in at the same time. I did not want to drop my oil pan in my driveway with no garage, so I had my shop do this work. I explained my oil pressure trouble to them, and asked that they check it out thoroughly once the oil pan was off and they were replacing the rear main. He told me that the bearings looked good, as did the rest of the bottom end. We opted to just replace the oil pump with a stock unit, as opposed to a high pressure one, based on these findings. Well I finally got the trans back in it today and tested her out. All looks good! A little over 50 psi full cold at idle, and holding in the 20-25 psi range full hot and in gear idling. This is a big improvement! This is using my stock gauge, which has actually been proven to be quite accurate with a mechanical gauge. Who knew that GM could actually make an accurate gauge? LOL I guess the moral is to never give up.

how much did the shop charge u to pull the oil pan out i need a new gasket

Just for the oil pan gasket would have been $350. They were great to me and did all the work for $620 which I thought was very fair.

 

[86_olds]

So I finally have an update. Looks as if the 307 will make it after all. I had the rear main seal replaced, and had a new oil pump put in at the same time. I did not want to drop my oil pan in my driveway with no garage, so I had my shop do this work. I explained my oil pressure trouble to them, and asked that they check it out thoroughly once the oil pan was off and they were replacing the rear main. He told me that the bearings looked good, as did the rest of the bottom end. We opted to just replace the oil pump with a stock unit, as opposed to a high pressure one, based on these findings. Well I finally got the trans back in it today and tested her out. All looks good! A little over 50 psi full cold at idle, and holding in the 20-25 psi range full hot and in gear idling. This is a big improvement! This is using my stock gauge, which has actually been proven to be quite accurate with a mechanical gauge. Who knew that GM could actually make an accurate gauge? LOL I guess the moral is to never give up.

how much did the shop charge u to pull the oil pan out i need a new gasket

Just for the oil pan gasket would have been $350. They were great to me and did all the work for $620 which I thought was very fair.

do u think its worth doing the gasket by ur self if u got access to a lift or you just rather pay cuz i think u got to lift the engine up