Thread: What heads?

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My 305 has everything going for it except the heads. I ported them but I'm looking for a set that will increase the air flow better than the small ones I have now. There are so many of them avaliable for the sbc I don't know which one to pick. It's a 1982 model from a GMC truck. With all that I've added I have 303 HP and 313 lbs. at the crank but with better heads I should be able to get another 30 HP out of the 305.

http://www.goingfaster.com/spo/343hp305.html this is a good one with stock heads.
http://www.hioutput.com/tech/400hp/400hp.html

Originally Posted by chevy 37

My 305 has everything going for it except the heads. I ported them but I'm looking for a set that will increase the air flow better than the small ones I have now. There are so many of them avaliable for the sbc I don't know which one to pick. It's a 1982 model from a GMC truck. With all that I've added I have 303 HP and 313 lbs. at the crank but with better heads I should be able to get another 30 HP out of the 305.

I would look at a set of the Dart Iron Eagle SS heads.
I would not go any larger than 165 cc port volume.

They make vortecs that will fit your motor. I think that the chambers are a little bigger but I know they flow much better then 305 heads. Would you be willing to part with your 305 heads? I'm currently looking for a cheap way to boost compression on a junk rebuilt 350.

Gerald I'm going to keep my 305 heads because I have ported them and might use them again. Thanks anyways.

Just pulled a set of heads off a running 305 engine, casting number 14014416. Mortec sez they are 1.84 intake and 1.5 exhaust. Maybe you chebbie guys know if they are any good. They are up for grabs, cheap.

Dave They are nothing but stock small heads. Put them on a 350 and your compression will go up but the engine won't breathe worth a crap.

Originally Posted by chevy 37

Dave They are nothing but stock small heads. Put them on a 350 and your compression will go up but the engine won't breathe worth a crap.

Yeah, they were on the engine I took out of Joe's Camaro, thought I'd see if anyone had any use for them. Probably going to get a set for my Camaro from Erik....

Oh yeah, got all the TPI stuff too, if anybody needs it....

Lunati used "generic" 305 iron cylinder heads (casting number=14014416, used on LG4 and HO engines), replacing the 1.84-inch stock valves with larger 1.94-inch valves, but kept the stock 1.50-inch exhaust valve size, treating both to a "good' standard valve job. They also ended up gasket-matching the heads and doing a little bowl work before installing Lunati high-performance springs, retainers, locks, screw-in studs, and pushrod guideplates.

Lunati's engine was tested on Dynotech's SuperFlow dyno using a generic set of 1 5/8-inch primary tube headers. The best results were obtained with the stock jetting and 38 degrees total timing, where a peak of 343 corrected horsepower at 6250 rpm was observed. The peak torque output of 356.2 lb-ft occurred at 4250 rpm. The engine made over 1 hp/cubic inch from 4500 through 6500 rpm, the highest rpm tested. It made over 300 lb-ft of torque from 3000 rpm (the lowest test point) through 5750 rpm.

Through all the tests, the engine idled smoothly at 750 rpm. Dynotech's technicians believe the engine would have more potential with less restrictive heads. They also think that the engine would perform better with a 650- or even 700-cfm carb, albeit at the cost of additional bottom-end sogginess.

Racing gas with a 108-octane level was used for all tests. This gas is not generally available for street cars. Assuming the use of 92- or 93-octane unleaded, you could get by with a true 9:1 to 9.5:1 compression ratio street motor when using cast-iron heads. The generally accepted rule of thumb is that you lose 12 to 15 hp for each point drop in compression-- so an otherwise identical 9 1/4:1 engine would be down about 15 hp from the results reported here. This lost power could be easily regained by using aluminum heads fitted with bore-clearing 1.94/1.50 or 1.55 valves, such as those offered by GM or Air Flow Research. Not only do the heads flow much better than 305 iron castings, but aluminum's superior heat-rejection characteristics allow 10:1 street engines on available unleaded premium pump gas. In any event, the end result is a 305 that will surprise quite a few late-model 350 owners.

Whew!!!!!!!!!!!!!!!!111

Just for everyone that believes the old wives tales about 305 engines being some sort of bad mojo /bermuda triangle of a boat anchor or that they must be made from a metal substandard to all other metals or any other hearsay type percieved ideas. Its made from the same metal as all other engines and theres no little gremlin inside stealing all the mojo magic from the combustion process to prevent this engine from responding to the same parts as a 350.The .100 smaller bore is not going to kill off 200 hp or restrict airflow down to 50 cfm. 45 cubic inches is the ONLY difference in these motors.Following the bigger is better logic , a 500 caddy motor is the only motor to start with ,all the rest are boat anchors{false}
There is no "special sauce" that was spread into a 305 mold to make it any different than every other small block ever made by chevy.

Here is a motor ,305, that supposedly has a blown head gaskett and a gallon of water in the crankcase to boot and is already used up from racing....Yeah I said racing and 305 in the same sentence .
http://fazed.org/video/?id=506

That is amazing. I guess that's why I keep my 305 even though I keep saying I'm going to replace it.

Yep me too! Sure a 350 with the same parts is going to make more power,but my point is the reliability and cost.Most people will sell a good running 305 for nothing or already have a 305.If you need the whole deal and a rebuild with machine work etc.you might as well get a 350 it will cost no more to build than the 305 at that point.But for a motor that basically gets given away and then adding a cam ,headers ,intake and carb and make close to 300 hp is no joke.Then the fact that when you use that motor up ,all the parts will fit a 350 block.Unless you are trying to make 9 gillion hp or going race only there is no reason not to consider the free or almost free 305 you may already have access to.Like said before ,if you need a complete rebuild ,you might as well do a 350. But there is no design flaw in the 305 that warrants absolutly not using a 305 for some situations.

If a 275 hp 305 was under the hood of one of the late 40s to late 50s autos from the factory it would have a legend status like the 327 Untill after the mid 60s a 300 hp street ride was up there in the muscle department.Sure there were blowers and tunnel rams on alot of the cars,but that was far from the norm.Today 300 hp is looked at like a briggs and straton engine and it should be upgraded fast as possible

Originally Posted by shawnlee28

Just for everyone that believes the old wives tales about 305 engines being some sort of bad mojo /bermuda triangle of a boat anchor or that they must be made from a metal substandard to all other metals or any other hearsay type percieved ideas. Its made from the same metal as all other engines and theres no little gremlin inside stealing all the mojo magic from the combustion process to prevent this engine from responding to the same parts as a 350.The .100 smaller bore is not going to kill off 200 hp or restrict airflow down to 50 cfm. 45 cubic inches is the ONLY difference in these motors.Following the bigger is better logic , a 500 caddy motor is the only motor to start with ,all the rest are boat anchors{false}
There is no "special sauce" that was spread into a 305 mold to make it any different than every other small block ever made by chevy.

Here is a motor ,305, that supposedly has a blown head gaskett and a gallon of water in the crankcase to boot and is already used up from racing....Yeah I said racing and 305 in the same sentence .
http://fazed.org/video/?id=506

OK.,here we go again back to the old basic's.
Have you ever weighed a set of 305 or 350 heads?
If you have then you would notice that the 305 heads are lighter in weight meaning less material.
The same thing applies for the 305 block.
I don't think they even made a 305 4 bolt did they.
Oh,by the way the bore difference is not .100 it is .260 which is more than a 1/4 of inch.

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