Vortecs on a 305?

[econo racer]

Will stock 350 vortecs fit on a 305? Or will the valves hit the bore? I have not pulled the 305 yet so I can not check. Thanks if you have any ideas.

[Orr89rocz]

They will work. Theres also a 305 vortec head i think its the 059 castings that may be looked into as an alternative

[F-BIRD'88]

Yes they fit. Use a 350 head gasket.

[Schurkey]

GM never used a valve larger than 1.85 on the 305 bore, even though they'd made zillions of 1.94 valve cylinder heads previously.

Wild guess: A 1.94 valve clears the bore...but is so shrouded that there's no point.

There's an ancient Trick Flow 2.02/1.60 head that will similarly clear a 305 bore, at least at low-to-moderate valve lift. One of the magazines did an article on that, but I'm unable to find a copy online. Again, the valves are likely so shrouded as to make it a pointless "upgrade".

[Tom68]

Doesn't anybody relieve bores anymore to match the chambers, was common with 4" bores and Fuellie heads in the 60s and 70s.

[1980RS]

I know of a few people that used the 350 Vortec heads on a 305 after they milled them a little to get the cc's down. Sure made more power.

[Justa1time]

I am very curious about these vortec 305 heads. Not much info on these & porting.

[turbo camino]

They didn't build nearly as many '96-'02 305s as they did 350s, for whatever reason.

https://www.rockauto.com/en/catalog/che ... +head,5304

[F-BIRD'88]

I am very curious about these vortec 305 heads. Not much info on these & porting.

The 305 version 305 vortec heads #059 have tons of potential. They flow pretty good as cast for the stock valve size. Lots of room to grow with porting and larger valves.
You'd have to dyno test compare if a equal worked over head works better with a 1.94 valve vs a 1.84 valve on a 305 .bore size engine (3.736")
It sure don't slow it down any..
A 2.02" valve will not fit a 305 cylinder bore.
A 1.94" is plenty big on this bore size.
And overbore increase is going to be a plus++.

[Schurkey]

A 2.02" valve will not fit a 305 cylinder bore.

Sure it will...but not at the OEM 23 degree valve angle.

Trick Flow Twisted Wedge 2.02/1.60 (original version, maybe not "Gen 2".)

[Orr89rocz]

GM never used a valve larger than 1.85 on the 305 bore, even though they'd made zillions of 1.94 valve cylinder heads previously.

Wild guess: A 1.94 valve clears the bore...but is so shrouded that there's no point.

There's an ancient Trick Flow 2.02/1.60 head that will similarly clear a 305 bore, at least at low-to-moderate valve lift. One of the magazines did an article on that, but I'm unable to find a copy online. Again, the valves are likely so shrouded as to make it a pointless "upgrade".

viewtopic.php?t=25162

I dont think its that shrouded. Maybe a tad

[BOOT]

Someone in a past thread, suggested L98 alum heads 128, 113 for a 305. Not sure how that worked out.

[1980RS]

All my circle track friends tried to run the Vortec 305 heads after these guys are big compression hounds, but the 906/062 Vortec heads always won out in the race until a lot of local tracks banned the Vortec heads all together. Why spend a ton of time on a 305 head when you can use the better 350 head stock with a valve job that makes great power and saves some money too boot.

[F-BIRD'88]

Stay away from those TFS Twisted Wedge heads (origional version) .Even if someone tries to give them to you..
A 2.02" valve will fit but only to a limited .430" valve lift.
At +/- .430" valve lift the 2.02" valve strikes the cylinder wall.
Not worth it either way.
Tons of power with a 1.94" valve max, without the hassle.
Yes the L98 aluminum heads fit and do need full on porting to perform. Stock As cast flow is modest.