Is there a difference? If the valve sizes are the same (1.94/1.50), is there really anything that makes it not work with a 305?

 

Doesn't matter the valve sizes, they'll still work. Prolly lower the compression though.

 

What happens to performance and gas milage when a 305 goes to 350 heads with 64cc chambers? I belive 58cc is stock for an LO3?

 

they have bigger combustion chambers so a lower compression ratio, also not the right size for proper combustion


so yes but no

 

So, what size would they need for proper combustion?

 

size of cylinder

causes some force to miss the piston and hit top of cylinder
ive heard this but never actualy tried to figure it uot

 

"Proper combustion" isn't the issue. It's compression ratio. It will reduce the power possible, but may actually improve power over stock 305 heads (which have 1.84/1.50 valves, BTW).

To maintain compression ratio, shave the heads to 58cc chambers. That's about .04" off of 64cc heads, which will require shaving the intake manifold, too. I wouldn't recommend trying it with 76cc heads.

 

Ah damnit I was looking for some good heads for a 305 to mate to my LT1 cam, that won't cost me $700. I'm not prepared to spend that kind of money. Is there a cheaper alternative out there somewhere?

 

I'll sell you my 1.94/1.5 350 heads.

 

How 'bout this.....1.94/1.50 valves, 64cc chambers with 9.0:1 compression ration?

 

the 9 to 1 depends on the pistons and is in a 350 not a 305

smaller displacement motor needs less combustion chamber for that compression ratio

 

By $700, I assume you're talking about World 305 heads. An alternative would be to get a set of TPI heads and port them. But, you'd need the 1.94" intake valves, and better valve springs. The press-in studs should be replaced with screw-in. They'd probably need a complete valve job, too, and guides are often worn on high-mileage factory heads.

By the time you do all that, the $700 isn't so far off. Besides, you get a lot for that money - new castings, 1.94"/1.50" valves, good springs, screw-in studs. The down-side is that they should be pocket ported (at least) to realize the most benefit.

1.94"/1.50" 64cc 350 heads are not all that bad on a 305. Use a steel shim head gasket to keep the compression loss down. The compression loss should be more than made up by the improved flow over your swirl-port TBI heads. Just make sure the springs can handle the cam lift you're planning. Still need to think about those press-in rocker studs, too.

 

I've been thinking of running those world heads. Just checked the Jegs catalog and those world heads s/r torquer 305 heads are $318 each. Not a bad deal for what you get. Specs below.

170cc Intake Runners. 30 HP Over most OE castings
(S/R Torquer 305: 1.940''x 1.500'')
(S/R Torquer 305: 58cc)
Dual Pattern Raised Valve Cover Rails.
Accepts All Early and Late Model Accessories.
Unleaded Fuel Compatible Hardened Exhaust Seats.
Manley 7° Chrome Moly Retainers
Valve Springs Are 1.250'' o.d. x 1.800'' Installed Height (100lbs Seat Pressure).
3/8'' Screw-In Hex Shoulder Rocker Arm Studs.
TRUE Bolt-On Installation.
Accepts Stock Pushrods.

 

They "work", as far as bolt-up and fit, but may be less than ideal because the compression is lower than it really needs to be. However, in many cases, the gain from the flow may offset the loss from the lower CR, especially if the car is geared to let it wind up a bit.

As an example, I have a set of 186 double-humps on this weenie little 305 in my 83 car right now, with a 5-speed and 3.73 gears. I'm running a XR264HR roller cam, 1.6 rockers, and 1.45" valve springs with them, and Edelbrock TES; everything else (carb, intake, all emissions devices, air cleaner, etc.) pretty much stock. It dyno'd 214 RWHP that way, about 260-265 at the crank, not much but at least a little better than stock. I only put that motor in to pass CA emissions, I'll be glad when I can get it back out and put the real motor for the car back in.

If I was going to actually spend money and effort on attempting to build up a hot 305, I'd probably go with the Worlds.

 

studdmstr (and anyone else to whom it may concern), couple of things to think about concerning World Products S/R Torquer 305 heads:

Those 100 lb seated pressure springs are better than stock, but not especially great. Consider upgrading when you order. I got the ZZ4-type springs when I got mine, it's been to 6300 several times without valve float (the stock springs floated at 5200).

I wouldn't call them a "true bolt-on installation". If you have center-bolt valve covers, you need to grind off the perimeter bolt bosses. And, after doing that, I found that my '87-vintage center-bolt covers wouldn't fit - too wide at the rails (World explained they used a set of early-'90's truck covers for their template, apparently the earlier ones were wider). Made sealing the perimeters a challenge with most of the bosses gone. But, you can't just take them out of the box and use center-bolt valve covers.

The heads as-delivered are pretty ugly in the bowl area. Why they stop their mill where they do, I don't know, and the guide casting is massive as it sticks into the port. Seriously consider a pocket porting job before bolting them on (every magazine article or test I've seen with these heads had a pocket porting job done), and grinding the guide bosses smooth. I spent the time to do the full SA guidelines porting and polishing job on mine, and don't regret it.

Finally, if you use your '89 rocker arms, you'll need to open up the pushrod holes, or you could get binding between the pushrod slots and the self-aligning rockers you have. If you get new rockers while you're at it, get non-SA and leave the pushrod slots alone.

I love the results using those heads, but I would NOT consider them a bolt-on. Moral of the story: buy the heads unassembled (save a few bucks there), since the work that should be done on them would best be done with them unassembled, anyway.

 

(oops, hit "quote" instead of "edit"...)

 

Thanks for the 411 on the world heads five7kid. I'll have to take the extra work into consideration when I get ready. While I've got the whole top end of the engine apart making the changes would you recommend changing out the cam while I'm at it?