Do 305 head fit on the 350??? Why would someone put 305 heads on a 350???

 

305 heads often have 58cc chambers compared to roughly 64cc chambers on some of the smaller- chambered "performance" Chevy heads. So 305 heads can give you a boost in compression.

Personally, since 305 heads are set up for a bore size that is even smaller than on a 283 (they get the 305 displacement by having a 3.48" "350" stroke), I think that they are always going to be limited to having no more than 1.94" intake valves work well in them. And most of the 305 heads aren't all that good either.

I'm sure that there will be somebody on here that can tell you how they have a good running 350 with 305 heads on it though.
I do have a low mileage 305 that runs like a top (for a stock, smog engine) already in a plain- jane '83. And I picked up a set of 305 Vortecs, so............. Who knows? Maybe I'll give it a try!

 

hey basic, there are 2 different versions of the Vortec 305 heads, you need to pull an intake valve and be sure you don't have the "swirl-port" version. They are out there. I've seen them.

 

A very common 305 swirl port head is the 14102187 casting. These are junk, in fact I have a set that came of the 305 in my 92. I plan on stripping and using for boat anchors since they are no good for anything else

 

Do they fit....yes... Why.... small combustion chamber for higher compression ratio, especially on base low compression 350 dished piston motors replacing a 76cc chamber head.

Not all the 305 heads are the same. Some like the #416 or #601 have good performance power potential on a 350 with full porting and larger 1.94x 1.6 valves.
Some chamber deshrouding/relieving is needed for the larger valves too.
Installing 2.02's in these heads is not recomended or required to get high performance.
Even the 416's and 601 have modest airflow in stock form, so the full benefit of the 305 head on a 350 head swap is not going to be realised unless you get busy with the porting work.
In fully ported modified form with larger 1.94x 1.60" valves:
These are the "Poor man's racing cylinder head"

Others like the 434 or 450 head have very restricted ports and tiny valves so their only real benefit is the higher compression ratio, when replacing a 76cc smog head on a 350.

 

I was saying beware of the '96-up Vortec swirl ports. But the pre-vortec swirl ports also suck.

 

See sig... Mine runs pretty good... Will have to get it dyno'd one of these days...

 

how many time...

there arent any "pre-vortec"..."vortec swirl port" there just isnt any such thing...

vortecs are 062's and 906's for the 350 there is a 305 casting out there dont remember the number off the top of my head...

but people are attaching the Buzzword like they always do "vortec" to a piece of crap 187 casting which is a TBI swirl port boat anchor... the only way it is pre vortec was that they started casting them atleast 10 years before they even thought of the vortec principles