small block heads?

[Irishman999]

Its time to start collecting parts for my 305 and was wondering if 350 vortec heads would fit the 305? someday this truck will need to pass emissions so would these even work?

 

[85k10383]

Was it the 350 head on a 305 that has the water jacket/passage alignment issue? Or is it the other way around? Now that I think of it, it was the other way around. People were putting the 305 heads on the 350 to bump up compression ratio, kinda like the 327 head on a 350 trick....

 

[Irishman999]

I was searching about it and learned they do match but it lowers the compression a ton. Im going for mileage here so maybe I will just stick with stockers.

 

[bucket]

There were Vortec 305's too, those heads would work great. You can have power AND efficiency

 

[GreaseDog]

Was it the 350 head on a 305 that has the water jacket/passage alignment issue? Or is it the other way around? Now that I think of it, it was the other way around. People were putting the 305 heads on the 350 to bump up compression ratio, kinda like the 327 head on a 350 trick....

there are no problems with any Gen I small block head bolting to any Gen I block, other than the steam holes for a 400. whoever told you that was wrong.

as for the "327 head on a 350 trick", there is no such thing.... they used teh same heads.

 

[Irishman999]

I was under the impression there was no 305 vortec! How exciting. I was thinking about an after market manifold, Is there one with the EGR i could use with those heads? Eventually I have to make this thing pass emissions, im okay for now registered in New Mexico.

 

[bucket]

The vortec 305 was usually found in the Express vans. There was an EGR pipe that threads into the exhaust manifold and then bolts to the intake. I assume there is an aftermarket manifold available that can use the EGR tube.

 

[Swims350]

I could understand his point on 350 heads with a 305 it would lower compression ratio due to the 350 heads having 64 cc or 72-76 whatever it is, and usually 305 heads have low numbers like 58cc and such. That would lower the compression ratio but you could have the heads shaved, block decked and install domed pistons for a 305, they make those right? That's alot of work to restore the compression lost. I'd find some 305 vortecs as mentioned and be done with it. Or, use what ya got.

 

[HotRodPC]

I'm for going for the 305 Vortecs too, all that machinging, decking the block, milling heads and dome pistons that might even need fly cut to not interefere with your valves colliding depending on the cam you are using, is a ridiculous expense. Just find some 305 Vortec heads is my vote, and 2nd choice would be just go back with 305 stockers. Those are out there a dime a dozen cuz most people updgrade to a 350 and trash the 305. I recently sold a set of stockers off a crate motor that had 40K miles on it and spit some rods thru the pan and block. The heads were still great. Sold them for $50 and the guy bolted them on and is as happy as a fat lady at an all you can eat buffet with deserts.

 

[Irishman999]

Im just waiting for a chance to buy some heads cheap on craigslist. I have seen plenty of vortec 350 heads, Since its my DD I wanna get everything ready so that one weekend I can just tear it down and rebuilt the top end of my motor.
I think before that maybe I will just get a compression tester and make sure I have some bad valves.

 

[Swims350]

when you see the auctions for the vortecs or craigslist ads you should get the castings, and see if you can narrow them down to find the cc of them, like see if you can find the 305 style 58cc ones or whatever. They might claim them to be 350 heads but have the small cc as said above any small block heads gonna fit on a small block, so check the numbers and see if you can find more info on them. You may find a set that say they are 350 heads but be the exact specs that the 305 had like small cc and such. I'd like to find a cheap set of vortec's for the 350 in my old man's 84, he's got like 76cc chambers and dished pistons so he has low CR and I want to bump it up for some more powah. I aint found any vortec's anywhere close to me for less then $300 a set, and most were online and auctions, so they could go up and shipping would have to be added on.

 

[GreaseDog]

The vortec 305 was usually found in the Express vans. There was an EGR pipe that threads into the exhaust manifold and then bolts to the intake. I assume there is an aftermarket manifold available that can use the EGR tube.

the Vortec 305 was available in everything a Vortec 350 was available in.

 

[GreaseDog]

I could understand his point on 350 heads with a 305 it would lower compression ratio due to the 350 heads having 64 cc or 72-76 whatever it is, and usually 305 heads have low numbers like 58cc and such. That would lower the compression ratio but you could have the heads shaved, block decked and install domed pistons for a 305, they make those right? That's alot of work to restore the compression lost. I'd find some 305 vortecs as mentioned and be done with it. Or, use what ya got.

installing domed pistons with a Vortec head is a bad idea. negates any gainst there are to be had with the Vortec's combustion chamber design.

 

[Swims350]

I don't mean only vortec 350 heads, I'm talking regular 350 heads. I wasn't even thinking 350 vortec's when I posted, I was thinking plane jane old 350 heads.

good info to know though and inform others. Only options to bump up CR then would be flat tops.

But again I'd just find some small cc vortec's and use em or use some stock 305 heads for a budget build.

 

[85k10383]

What was the Vortec 305 nomenclatured as? A 5.0 Vortec? I'm just curious.