I am thinking of purchasing a new set of heads for my 305. I was looking into a set of Edelbrock performers. Any one out there have any suggestions??

 

Well, to reiterate what I recently found out. Not much in the way of choices. Only direct bolt in is World Products SR Torquers. Otherwise there are a copule of others (350 heads) that will work with some modification. One is made by Trickflow and the other is the Aluminium L98 (I believe) vette heads. Both need a degree of modification to work like the OEM heads or the World Products SRs would. E.g. the vette heads have some difference with the EGR it think. And I'm not sure how much the 350 heads would affect your CR.

I'm starting to think of selling the 305 and going with an LS1 swap .

 

Well, pretty much any head with no bigger than 1.94/1.5 valves works on a 305. The problem becomes how much they flow, and how much flow you could get out of your stock heads if you ported them. Odds are, unless you've invested a lot, your 305 doesn't flow enough air to justify spending big bucks on bigger heads (i.e. AFR 190's). Unless you've done extensive modifications (since this is the power adder board) like a large turbo, or a supercharger that's pumping out at least 8 psi of boost, aftermarket heads like AFR's will flow too much. However, if you slapped a D1SC on your 305 (and after all the necessary fuel/ignition upgrades) then you could justify some good heads. Otherwise, just slap some World Torquer 305's on there or just heavily port the ones you have and get a 3 angle valve job.

Jon

 

I'm running the aluminum L98 heads. They have a 58cc chamber so don't affect compression. I like them a lot.

 

dont forget there is a head similar to the L31 vortec's (vortec 5700) made for the 305 (vortec 5000) that has the similar flow charachteristics and the 305 friendly valve and combustion chamber sizes.

 

Any head will fit the 305. 2.02/1.60 will fit just fine. Shrouding starts to become an issue at .550" lift though.

All aluminum heads need to be 54cc and cast iron 58cc for 305s.

Vette L98 heads have no EGR.

The L30 Vortec heads (as B4C mentioned) borrow a lot of design characteristics from the L31 Vortec heads and LT1 designs. They can be a great bolt-on 305 head (good luck finding a set)

 

So, what you're saying is as long as you run a low lift cam (like a stocker in a blown application), one could use any of those wonderful aftermarket heads available?

Jon

 

Exactly. I've personally taken a look up through the crankshaft valley at 2.02/1.6 heads on a 305 and they appear to fit perfectly. But once you get past lifts of .550", then a shrouding issue becomes eminent. Just keep the lift lower than .550 and you will be smooth sailing.

 

Being fairly new to head rebuild terminology, What is "shrouding"???????

 

Porting
It´s a F*rd site, but there´s a picture.
HTH

 

shrouding is the resultant loss of air flow from a larger valve being closer to the cylinder bore of the engine. since the valve is at a 23 degree angle to the sides of the cylinder bore, not only can some cams cause a dangerous touching interferrence but also an airflow interferrence. this close clearance causes a restriction of flow and swirl to critical hp and good combustion. "shrouding" is the word used in referrence to an engine with a too large of valve and/or too small of cylinder. whereas a 2.02 intake valve is nice on a 350 with its large 4" bore a 2.02 intake valve is argueably too large for the 3.7XX" bore of a 305. a 1.94" valve is also argueably too large also when used in a 305 for the same reason. as in all things there are exceptions to this rule. world products sell a high performance head called a 305 s/r torquer. it is of similar design to the regular s/r torquer. only it is made just for the small bore engines like the 265,283,305, and 307. it does use 1.94/1.5" valve but uses a custom layout which keeps the valves closer to each other. this precludes putting larger valves in, but the 1.94/1.5 has good flow (xtra-sufficient) for a 305. it also has the desirable 58cc combustion chaimber size. they have addressed all of the necessary problems including shrouding. if memory serves correct it even has more flow and larger ports than the L98 aluminum head. this head I believe is offered in late and early intake patterns and accepts early or late V.covers a complete PDF (adobe) file on the head is available at http://www.worldcastings.com/tech/RTorquer305Tech.pdf also. I actually put 23 hours of port work into a set of 1985 305 iroc heads with the 1.83/1.5 valves in it and before we could get them on a flow bench they went on a 1/8 mile black top circle track car with a barely used 350 out of a 79 vette. just before the local points chase he blew up his nicer "race" motor. he was unsure the small valves would be enough but the guy won the track championship and bought them from me unflowed after the first heat race with the biggest smile on his face. bigger is not always better, just look how the out of the box vortec L31 heads with the stock 1.94/1.5 valves outflows the 2.02/1.5 bowtie race head out of the box. it does out flow and out "port velocity" (resulting in more torque also) that larger valve head. that guy revved that circle burner to 6K and the thing out pulled every car. they tore him down because they thought he was using "a solid cam or domed pistons or something..."