Ok,I am getting ready to tear down my 283 and go through it.I am wondering if any of you have ever tried to use 305 heads on a 283 I know it has bigger valves but are there any real gains to be made.This is a 4 wheel drive so it doesn't need to make power at 7,000 R.P.M.'s Oh yeah I already have the 305 heads that is why I got to wondering.Thanks.

 

no idea about those engines but Im shore if the heads flow better it should make more power

 

what size is the cumbustion chamber compared to teh 2

 

Here is my 283 recipe for you....bore it out to 4.00 inches, use flat-top pistons, use the "double hump" 305 heads from like an L69 motor (don't use just any old heads just because they are from a 305) use a Comp 268h cam, a performer rpm intake and a 650 spreadbore holley (or even better a TPI setup off a 305) This combo will get you pretty much all the streetable power there is to be had with that small motor.

 

That sounds like a good recipe, I was wondering what kind of gains would be made with just any old 305 head because that's what I have I don't really have the money to pick and choose all of the good parts I was just wondering what kind of help that would be to my little motor.Thank you and if anyone else has any ideas that would be relly appreciated.

 

When I was circle track racing, we used the 305 heads alot in the stock classes. You can have them cut for 1.94 intake valves pretty cheep and they flowed decent. They also have a smaller 58 cc combustion camber which would up the compression a bit. Every one started running them, so then the out lawed them...go figure. If I was doing a build on the cheap, I would run them.

 

i'm thinking there will be a flow issue with the "smogmaster 305" heads, with the poor combustion chamber and port design, combined with the tiny valves these heads come with. you could of course cut the seats to the 1.94/1.6 valves, but the inefficient combustion chamber and the flow challenged ports would negate anything gained with the increased valve size. you also said cost was an issue. anywork will be $$$ and really for naught. IMHO if you want to open the 283 up to a 4" (can it be taken that far?) save the money from working the 305 heads and get some vortec heads off of a 96-98 5.7 truck. these can be had from a salvage fairly cheap and if they are good heads a simple valve job is all you would need. would have to keep the lift down to about .475 unless you had the valve guide boss machined. or save your money and you can buy a ready to go set of the vortecs from SDPC for about $600 and they already have everything done to them and can handle .550 (or .600 i think) lift. this would still be a short-stroke 7K screamer for relatively little money.

 

Just dont forget you need an intake manifold with the vortec port and bolt pattern. Also they have no internal EGR passage if you have any need for that stuff. I used vortec heads on a 383 engine I had in my Yukon and they worked well.