305 heads on a 383 stroker?

[Rreemo]

I've played in this space a lot in the past....trust me on this, you do not want to run those 305 heads on a stroker motor!

As mentioned elsewhere, they are a cheap HP alternative on a 350, but that is only b/c of the 58cc chambers....a 350 has a 3.5" stroke (3.48" to be exact), which combined with those smaller combusion chambers will net you in the ~11:1 compression range (give or take depending on piston, head gasket thickness, deck clearance, etc).

The issue you run into with a 383 is that you are stepping up to a 3.75" stroke with that 400 crank. When you combine that with those smaller chambers, you are now cranking your compression up beyond streetable levels....~12:1+ (give or take on the same varibles as above)

Beyond this, the tiny valves and runners in those 305 heads aren't going to be at all sufficient to support 383 cubes. Again, they will do okay on a 350 up to around 4500 rpm, but a 383 is a whole different animal.

To give you an example, I used to have a budget built 406 that I ran a set of good ole 461 heads on (double-humps) which are 64cc...with flat top pistons that engine still made just a little more than 11.5:1 and I was running a thick head gasket too. With a decent flat tappet solid cam it ran pretty hard....made awesome torque, but I still had to run race gas in it....on the street I could get by turning the timing back and cutting 108 octane half-and-half with 93...but that was bare minimum.

The Vortech heads are a good recommendation if you are on a budget....just be sure about which ones you get...some of those castings still had 64cc, and if milled a little, you are still going to be pushing well over 11:1. In your situation you're going to want to run something more in the 72cc range (as long as you are staying with flat tops)....which should put you around 10.5:1 - perfect for a streeter.

Depending on how tight your budget is, you could also get by running a set of the 882 castings, commonly referred to as "truck heads"....I believe they were stock around 75cc, and they are cheap and plentiful. You can find those all day long for $300 or less fresh and ready to go.

Here's some more resources for you:

http://www.mortec.com - a great place to reference casting numbers.

http://www.csgnetwork.com/compcalc.html - a qwk and easy compression calculator.

Feel free to PM me as well....I've been around the block on this stuff and happy to answer questions for you.

Good luck!