Vortec heads on 305?

[econo racer]

I have a new set of 350 vortec heads stock,will the valves hit the 305 narrow bore. They have 64cc.s and the 305 is a flat top piston. Thanks

[mag2555]

The valves I think will clear the 3.74" Bore , but the over hang of the chamber will likley negate the flow gain the could provide you.

[BillK]

And you will also lose a lot of compression because of the larger chambers on the 350 heads compared to the 305 heads.

[Carnut1]

GM has a 305 vortec casting. Aftermarket as well. I would look for them for this build.

[Elroy]

305 Vortec heads look very little like 350 vortec heads. They do not possess the 906 or 062 style chamber which is in my opinion the bread and butter of the vortec design.

I would run a 350 vortec on a 305 over a 305 vortec////or a 305 head of any kind really. They aren't perfectly ideal due to the chamber being too wide for the 305 bore but its still a better compromise and a person could always get crafty and do some bore matching to a 906 or 062 head. But come to think of it// I can't see myself spending a lot of time on a 305 period but its always to each their own.

[F-BIRD'88]

The chamber of a stock 305 head also overhangs the cylinder bore on a 305. .... So.....
The cr will be low unless head is milled or use a 305 domed Piston. (Eg: KB144) Use a 350 .015" shim gasket

But just right for supercharging a 305.
Flat to 305 + vortec heads + a (any) blower = very nice power and perf. This is where the 144-142 lil roots blowers can shine.

Note,, the 305 vortec head can be ported to flow impressively and also responds to larger valves
Casting 059

[F-BIRD'88]

For N/A with 305 flat tops you want to mill the 64cc vortec heads to 59cc and use a felpro 350 steel shin gasket ,015"..
9.8:1 cr. (1.56 CH piston)