i am thinking of purchasing a set of 305 vortec heads for a .080 chevy 350. i am not sure of any differences in the 305 and 350 heads(i.e. valves, cc, and ports). would this be a worth while mod. any help would be appreciated. thanks

I wouldn't do it. How much are you paying for them?
I got a used set in real good shape from a place on car-part.com. Cost me $240 a pair delivered, with rocker arms.

they will cost me $200. But that is for the complete set up. rocker arms, pushrods, and valve covers. just needs an intake.

Be carefull of the CR. I believe the 305's have 53cc chambers yielding a CR of 11:1. To high for pump gas reliability.

I agree it would give a very high compression ratio. But for econoomy putting those heads on a 305 again, that would be great. If you dont want them do you want to sell them??

i did some research on vortec heads, and i found that the 98 heads are 64cc, but have 1.84int and 1.5 exh valves. how much would the 1.84 int effect performance? i couldn't find any thing on the runners or any other year. I am not sure which year motor the heads are off of, also not sure if there is any difference.

Hi. I am also looking at some Vortec heads for my 327. they have 58cc chambers and i was wondering what compression ratio that would get me, and also might there be any interference with my valves.... any info will help. thanks

My stockcar rule book says I cant use camel bump heads so I put 305 heads on.(flat top 355)The power is unbaliveable.The engine sounds totally diffrent to; it has a throaty bark sound to it.Everyone thinks I am running a 400 just because of the power and sound.It works great!!!

what kind of hp are you getting and what kind of cam intake and carb are you useing

put these heads on a 350 and you will have a complete powerhouse trust me I've done it!!!!!

i have a camaro with 55cc 305 heads giving me 11:1 compression it runs fine on 93 octane

From what chevy high performance magazine says. The 305 vortec heads are not the same as the 350`s, they do not recommend they be used, they have a smaller port and don`t flow enough. this is not to say they won`t work, they will, but if you used the correct 350 vortec heads it would easily make 30 plus more horses than the 305 heads. placing 305 heads on a 350 is the same as making it breathe through a straw, the engine will be real throttle responsive and have good low end power, but will be a dead player from 3500 RPM and up. as for 11:1 compression on 93 octane gas, the only way that can be done is by using a big cam that bleeds off some cylinder pressure, or the timing set so low it wouldn`t make much power so what`s the point? many guys do this, and many have asked me about it, and I say don`t waste your time, we did it years ago, we ported a set of 305 heads and put them on a 350 with a bigger cam, headers, intake, carb, hot igntion and headers, it ran a decent time in the 8th mile, the next year we added a set of dart II heads and no other changes, it ran almost a half a second faster. you have to remember, flow IS power.

I have 96 GMC 305 motor w/vortec heads edlebrock intake, gas carb w/ electric shock and electric gas pump. In my 82 cutlass This motor isn't giving me the speed that I'm looking for or it's just the dame motor thats not powerful engouh, The tranny is a 350 it needs a shift kit and a stallconvertor.
Need HELP!! on this one, don't know if the tranny or the motor thats not shooting power to the stander rear end 2.41 ratio to burn rubber.

sounds to me you need a little lower rear end ratio and a little more engine. are you sure It's a 241 ratio? If so it's to high of a gear to burn the tires.