head question

[cdg1984]

I dont know a whole lot about heads, and i was wondering if there would be any advantage of putting 305 heads on my 350. Im thinking the smaller combustion chamber would create more compression. I realize this isnt near as good as getting a really good set of heads, but i have a spare set of 305 heads in my garage and was thinking about cleaning them up and throwing a few hundered bux at them if it would be worth it.

 

[cdg1984]

Seirously??..? No one knows anything about this?

 

[monte olrac]

bad idea, what you gain in compression you'll loose in flow, those heads flow like a stop sign, you have excellent throttle response until about 4000rpm and you'll be very pissed when that honda puts a ninja whompin action on you.

 

[cdg1984]

bad idea, what you gain in compression you'll loose in flow, those heads flow like a stop sign, you have excellent throttle response until about 4000rpm and you'll be very pissed when that honda puts a ninja whompin action on you.

Well I was going to port and polish them as well, would that help at all?

 

[80_cutlass]

Way back in 90s, all the roundy-pounders I knew were hunting the "big valve" 305 heads for their race motors....now, I don't know much about Chevy motors, but I remember that. I'm not sure what castings and all because I was only eavesdropping at the machine shop.

Maybe some of the chevy gurus can shed some light on this.

sb

 

[cdg1984]

Anyone else have any knowledge of this kind of thing?

 

[chevyman454]

you got to look at it from a flow point of view. the heads you want to use may increase head pressure but as far as flow goes its really not there id opt for selling the heads get a nice set of good flowing heads

the heads flow at 150 cfm a set of stock 350 heads flow from 170 cfm and up when you port them
and if you are thinking of trying to get them to flow at around 170-80 dont try it. theres not enough casting behind it you will be ending up cutting into the water jacket and filling the hole with JB weld.

id just hold out for a pair of camel hump fuelies or getting a nice set of heads for cheap
if you need a set ill sell you the 1.94's i got 72cc for 150

 

[monte olrac]

bad idea, what you gain in compression you'll loose in flow, those heads flow like a stop sign, you have excellent throttle response until about 4000rpm and you'll be very pissed when that honda puts a ninja whompin action on you.

Well I was going to port and polish them as well, would that help at all?

Yes it will help...help you spend more money on poo poo heads, it's better just to get some good heads and call it a dayif you want to bring compression up just get them milled, you'll be happier in the end result

 

[86Cutlass383SR]

You're not going to take a set of smogger heads and make them flow any decent amount of air. Not even if you have a flow bench. Help, yeah. Better than they were. But still dismal by true performance standards.

Like was mentioned, start with good heads. If you still want to spend time porting, your outcome will be all for the better and not wasted on something that won't flow no matter how much time you spend on them.

You don't want heads with big ports for the street. You want heads that flow... aka velocity.

"those heads flow like a stop sign..." LOL, that was a good analagy.

 

[cdg1984]

Thanks for the info guys, I dont think ill be doing it. Im still a bit curious to see how it would perform. Mabye if I come across a junk 350 ill do it, just as an expierement.