Are all 307's basically the same?

[bonesninja]

So I have my 86 Salon that needs some engine work and I also have a 307 out of an 83 delta that I could save myself some time by having it rebuilt while i'm driving the car still. I know there is a difference in the heads but could I take the block, internals and the heads on the 83 and drop them in the 86 with my current intake carb and accesories?

 

[FE3X CLONE]

The earlier 307 would be a better choice for performance due to the heads and non-roller camshaft. All of your accessories and such from your '86 will bolt up just fine. However, while your intake on the '86 would bolt up to the '83, its going to have severe port mismatch.
That's assuming your 307 has the swirl port 7A heads and matching intake. Really, what you'd want is an intake off an earlier 307 or you could run an aftermarket intake if you wanted.

 

[bonesninja]

The earlier 307 would be a better choice for performance due to the heads and non-roller camshaft. All of your accessories and such from your '86 will bolt up just fine. However, while your intake on the '86 would bolt up to the '83, its going to have severe port mismatch.
That's assuming your 307 has the swirl port 7A heads and matching intake. Really, what you'd want is an intake off an earlier 307 or you could run an aftermarket intake if you wanted.

thanks, I'm thinking I'll just grab up an Edelbrock intake then. This is gonna save me alot of time on the rebuild, instead of having them rebuild the engine thats currently in the car.

 

[FE3X CLONE]

Are you absolutely set on building another 307? A 350 or 403 Olds will drop directly in a 307's place and you could still use all of your accessories you have on the 307.

 

[bonesninja]

Are you absolutely set on building another 307? A 350 or 403 Olds will drop directly in a 307's place and you could still use all of your accessories you have on the 307.

i really wanted an olds 350 but I have around $4k to spend total on the car. I need the brakes redone, some suspension componants, etc. I'm not a "performance" oriented guy, and I already have the other 307, so it made the most sense from a finance standpoint.

 

[FE3X CLONE]

Ah, I see.

If you do end up wanting something else, I know my friend has a complete 403 with Edelbrock intake he's been trying to sell. When he got it it was supposed to have been pulled while running but he said he's never verified that. He did say it spins freely.

I think he was asking $250 for the complete engine if your interested later on.

 

[dogsht]

I would second Andrew's idea. Even if you are not an "I need performance" guy. Most everybody appreciates a stronger engine that moves the car more easily. The 403 certainly has the potential for that and looks to be less money in this case as well.

 

[Minion1186]

mid 1985 all 307s were converted to roller lifters and cam,and the swirl port 7a heads,these heads are junk when it comes to any performance.I would take the 83 307 because it has the better suited 5a heads,with non rollers and they had about a 10 horsepower increase over the 7a 307s.If you just want the 5a heads,for the swap you'll need all the valvetrain components from the 5a 307,along with the a-4 intake,7a and 5a intakes were completely different despite how they look alike from the top,the ports just wont match up if you mix the heads and intakes up.The exhasut maniifolds were also different between the two,use the 5a exhaust manifolds with the 5a heads,use 7a exhaust manifolds with 7a heads,etc.If going for a rebuild,have them bore it over .40,port the head mildy and run a non ccc carb and distributor,just for that added performance.Loo in my signature,a 313 olds v8 (307 .40 over) and port matched heads,it had the ccc controls on it and it ran ok,considering the horrible 256 hears in the back,adding an earlier 307 should help

 

[bonesninja]

mid 1985 all 307s were converted to roller lifters and cam,and the swirl port 7a heads,these heads are junk when it comes to any performance.I would take the 83 307 because it has the better suited 5a heads,with non rollers and they had about a 10 horsepower increase over the 7a 307s.If you just want the 5a heads,for the swap you'll need all the valvetrain components from the 5a 307,along with the a-4 intake,7a and 5a intakes were completely different despite how they look alike from the top,the ports just wont match up if you mix the heads and intakes up.The exhasut maniifolds were also different between the two,use the 5a exhaust manifolds with the 5a heads,use 7a exhaust manifolds with 7a heads,etc.If going for a rebuild,have them bore it over .40,port the head mildy and run a non ccc carb and distributor,just for that added performance.Loo in my signature,a 313 olds v8 (307 .40 over) and port matched heads,it had the ccc controls on it and it ran ok,considering the horrible 256 hears in the back,adding an earlier 307 should help

Gonna go with the 83 307 and an Edelbrock EDL-3711 intake, new carb, and I'll be going headers because I don't have the original exhaust manifolds from the 83. Gona stick with the CC carb and distributor for now.

 

[FE3X CLONE]

I would second Andrew's idea. Even if you are not an "I need performance" guy. Most everybody appreciates a stronger engine that moves the car more easily. The 403 certainly has the potential for that and looks to be less money in this case as well.

Yeah. This is always the dilema when rebuilding a 307. All the machine work that would go into a 307 could be done to a 350 or 403 for the same amount but yet you'd come out with more cubes and power.