1.94" intake valve on 305

[ap72]

What are everyone's thoughts on a 1.94" valve on a small bore 305? Are there gains or is the shrouding so bad it's not worth the effort?

[pdq67]

Probably be fine as long as you use a lift limited cam so that there isn't any chance the valve can hit the top of the cylinder.

If you hunt hard, somebody has posted thoughts on big valve heads with max valve lift on smaller bore blocks. Good info, but I forget where it is??

Might think about relieving the top of each cylinder like BBC blocks are done stock. Just don't go down below where the top ring rides. I forget if the SB head gaskets allow for this or not so please check.....

Just things to think about here. Hope I've helped.

pdq67

[F-BIRD'88]

You don't need to notch 305 cylinder walls
For a 1.94" valve in a 305 head casting. But 2.02" valve w/high lift yes.
Remember a oem 305 head eg 4416 has a tighter in/ex valve spacing
Than old sbc heads.

Allsaid and done the bigger the overbore eg+.040"
The better.

If you are refering to adding a larger 1.94" valve to
A oem 305 head, (1.72-1.84" valve) yes you want to deshroud that
Chamber some. If its a 062 vortec head going on it, just run it.

Sticking a large chamber say 441, 487 1.94 head
On a 305 can benefit with cylinder bore notching
Because of the big chamber overhang on a small bore.
(Budget supercharger low cr motor build)

[F-BIRD'88]

So it depends on what head w 1.94" valve.

The chamber deshrouding job you'd do to a modded
305 head with larger 1.94" valves added that is going
On a 350 is different than if its going on a 305.
Cause the 305 bore is smaller.

[user-612937456]

It's been a long time but I think I had a 1984 HO304 Z28 at one time and I think it had 194 valves from the factory when I built a 355 for it I remember using the 305 heads on the 355. I could be wrong cause it was a few years ago in the early 90's

[Walter R. Malik]

Move the intake guide over toward the exhaust about .060" in the 305 head before enlarging the seat and it works great.

The DART heads already had relocated intake guides and came with 1.94" intake valves.

[ap72]

Move the intake guide over toward the exhaust about .060" before enlarging the seat and it works great.

And without moving it?

[Walter R. Malik]

Move the intake guide over toward the exhaust about .060" before enlarging the seat and it works great.

And without moving it?

I have never done it without using a .502" o.d. guide to move over the guide centerline and re-machining the spring seats.

[cv67]

How does one move the guide over properly always wondered about that

[vortecpro]

Knowing what can be done with a 305 with a 1.840 valve, I would probably stick with the 1.840 valve.

[Carnut1]

20141227_180523.jpeg

305 heads have the same valve spacing as every sbc so 2.055/1.6 valves will fit just not on a 305 bore.

[F-BIRD'88]

Are you playing with a oem 305 head, adding a 1.94" valve, going onto a 305
Sbc? Over bored...or stock bore?
Define "worth it".

If you spray the garden hose thru the intake port you will see where and how
Stuff flows into the cylinder.
Stick a valve in at various lifts to see its effect.

I say a 1.94" valve with some suitable chamber work is worth it.
Its better(er).

But:
Little if any net real gain on a 305 head with larger (2.02")
Not worth it especially on a 305 bore.

[Carnut1]

305bore.jpg

looks like a 1,94 / 1.5 305 head to me. Found this on the web with no actual facts attached. If I were to run 1.94 on a 305 bore I would check the clearance/shrouding like this before cutting the valve seats. Core shift could be a problem and need grinding.

[F-BIRD'88]

If you are trying to make hp, then what you do to the ports w a 1.94" valve matters
More. If your goal is to not do work,, "not worth it"

Then..... its very subjective. If you want a internet answer there are many google
Examples of 1.94" valve heads on 305's making very good power.
Eg L-31 vortecs eg: 041 w 1.94 valve. No mention of cylinder bore notching.
Lots of facts including dyno tests.

[ap72]

I guess I need to be more specific. Does anyone have any A B tests on a 305 when converting to a 1.94 valve. Dyno, track, anything?

Or does anyone have any flow data for a 305 head with 1.84/1.94 on a 305 bore fixture?