307 to 350 olds swap

[Raven87]

Hello again. Got some questions....
Ive done alot of reading and things about the swapping of a 307 to a 350 olds in an 87 cutlass. I want to basically drop the 350 in and make it look factory,ie: keep the electronic qjet, intake, AC, and everything else. My concerns are this:
Ive heard there are issues with the 307 intake working on the 350 ,as i want to retain the intake it came with in the car(307) and will i absolutely have to rejet the carb as im no carb guy.Basically i want it to look like it came factory with everything hooked up(wires and all)! Please tell me im not nuts lol!
Thanks guys!

Oh and heres the #'s on the 350: 395558 and it has #8 heads

 

[DoubleV]

You'll need an A4 intake which is the intake found on the earlier 307's. They practically look identical to your current A5 intake ( which is crap ). You'll also want to get the exhaust manifolds from an early 307 too because the 'tubular' exhaust manifolds found on the later 307's like yours are garbage. Strangly, some late model 307's came with the earlier exhaust manifolds, so check to make sure you don't already have a set. This is the style you don't want; http://www.ebay.com/itm/NINETY-EIGHT-CU ... 10&vxp=mtr

 

[Raven87]

Im sure they dont but ill ask,do all the 307/350 manifolds have the cross over or not? I may actually do away with the manifolds if i knew of a type of header that fit WELL and wasnt a hassle to fool with. She already has duels as they have removed the crossover pipe and capped the hole in the manifold with piece of metal and welded it up. And these #8 heads are junk right??? I appreciate the help as im new here still and hope to get to know more fellow gbodiers!

 

[DoubleV]

Im sure they dont but ill ask,do all the 307/350 manifolds have the cross over or not?

Yes.

I may actually do away with the manifolds if i knew of a type of header that fit WELL and wasnt a hassle to fool with.

The only headers guarenteed to fit perfect are the American Racing headers but they are expensive. Worth every penny though.

And these #8 heads are junk right???

No, they are good, but have 2 big downfalls though. First, they have huge combustion chambers which lowers the compression ratio. That can sometimes be a good thing though as they will keep your CR in a nice, managable range if you are rebuilding the engine with new flat top pistons. If one wanted to build a high compression motor though, they would be a poor choice.

The other issue with the #8's are poor exhaust flow due to alot of extra material behind the exhaust valves. This extra material can be cleaned up though and would make them flow on par with the earler 350 heads. The #8's do come with bigger exhaust valves vs the 350 early 350 heads though.

 

[joeairforce]

This is what I was going to use as a guide for doing the heads..

http://www.members.shaw.ca/gregtsmith/Head_Porting.htm

 

[Raven87]

Thanks DoubleV for the info, and a big thanks to joeairforce for the motor! Ill keep everyone posted on the build soon as i get into it.

 

[Raven87]

OH another stupid question , is my distributor(the stock 307 electronic) a swap out thing vs the points one thats in this motor?

 

[Bar50]

Yes, it will swap out.

If you have the 350 motor out and accessible, I would suggest replacing the teflon lined timing gear set with an all metal version. The teflon gets (trust me its already happened!) brittle and falls into the oil pan. Way easier to fix before you install the motor....

 

[Raven87]

Yes the motor is out and fixing to be tore down for a rebuild.Yea i always hated the "plastic teeth" that end up in the pan too...

 

[Raven87]

What are these W/Z exhaust manifolds i am hearing about? Are they for the 400-455, or will they fit the sbo too? Im afraid to try and go the "header" route so im trying to find the best flowing manifolds for the sbo i can and i do not want the cross over pipe.