Thread: 305 heads junk?

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#1, Tech., with all due respect, I have done it with a sbc 350,and a Ford 302 (78 model) and there is no,absolutely no,piston noise. Yes it does happen sometimes but your invited to the southside of Columbus to hear for yourself,or if you know anyone here,send them. Also will be glad to tear the heads off to prove it if they will just bring a gasket set for my trouble. Come listen,,,
#2 Bill,no,no, I didn't say anything about the 305 heads being better than 350 base heads,we would have to see real world dyno results. What I did say was that 305 heads can get my vehicle in the 14's. Thats what I am content with so why put my hard earned money in some fat cats pocket for another set. ALSO, I will argue that with the particular motor combination that I am useing,the higher compression 305 head will out-perform the sick base 350 head. It's not a choice between the two sets that I had anymore,I put the 350 heads on the 305 and will sell it. So, that junk 305 head 'won't' flow enough on 'any' motor to run better than high 14's? That's the impression I get from those that criticize 305 heads. That they won't work over 55 mph,geesh.I know they are not race heads but I also know that they will flow enough to make a 350 run quicker than 14's.Want to come to National Trail Raceway this year and see if they will flow anything or not?

Originally posted by billlsbird
DA, hey Tech Inspector, If I put the pistons in UPSIDE DOWN, how much Horse Power will I gain??? zzz

Bill, I'm not sure what you mean by this, but there is horsepower to be gained by mounting the pistons so that the pin offset is the other way, notwithstanding valve relief problems (arrow on piston pointed to the rear of the block). Hot rodders have been doing it for years.

Originally posted by techinspector1
Bill, I'm not sure what you mean by this, but there is horsepower to be gained by mounting the pistons so that the pin offset is the other way, notwithstanding valve relief problems (arrow on piston pointed to the rear of the block). Hot rodders have been doing it for years.

.....I was just fooling with Chevy Hemi, by unside down I meant the wrong side up, connectiong rod on the top.... bill

Originally posted by shevy not heme
#1, Tech., with all due respect, I have done it with a sbc 350,and a Ford 302 (78 model) and there is no,absolutely no,piston noise. Yes it does happen sometimes but your invited to the southside of Columbus to hear for yourself,or if you know anyone here,send them. Also will be glad to tear the heads off to prove it if they will just bring a gasket set for my trouble. Come listen,,,
#2 Bill,no,no, I didn't say anything about the 305 heads being better than 350 base heads,we would have to see real world dyno results. What I did say was that 305 heads can get my vehicle in the 14's. Thats what I am content with so why put my hard earned money in some fat cats pocket for another set. ALSO, I will argue that with the particular motor combination that I am useing,the higher compression 305 head will out-perform the sick base 350 head. It's not a choice between the two sets that I had anymore,I put the 350 heads on the 305 and will sell it. So, that junk 305 head 'won't' flow enough on 'any' motor to run better than high 14's? That's the impression I get from those that criticize 305 heads. That they won't work over 55 mph,geesh.I know they are not race heads but I also know that they will flow enough to make a 350 run quicker than 14's.Want to come to National Trail Raceway this year and see if they will flow anything or not?

.....hummm, come to the National Trail Raceway??? Can I sleep on your couch??? Carefull, I'm retired, I have the time ..... No, all I was saying was I'd use the 350 heads, but just my opinion. Yes, you can get in the 14's with your 305 heads, especially if your willing to run race gas. With a 2800 pound car you need 235 HP {flywheel} to go 14.5.... That's according to the calculator thats at campenterprises.com... Of course there are a lot variables that this isn't considering. The '84 Camaro that I had with a 305 had {I think, it's been awhile} 195 HP??? or was it 185??? I just liked some of the ideas that you got on milling the 350 heads if you want more compression. Also someone mentioned that the 305 heads didn't 'fit' the bore size of the 350 very well......

Bill,Techinspector,other replies, I wasn't bragging up 305 heads, I was defending the rap that they won't work on a mild build up with the right combination of parts,when race heads are not needed. Actually if someone had the money and was building an all out drag car, heads would be at the top of my list, right behind traction/suspension. Thats the place to start,or perhaps the place to put the money.
I read the posts, I have the mag. subscriptions,I have bought the products,the right ones and the wrong ones at times. All the talk is around high dollar,top of the line products,which I agree with as long as it is the 'right' combination. However,,,there are many of us that don't have the money or the desire to compete with the big boys. Neither am I saying that something like 305 heads is a place to start, not at all. What I am saying is that too many brag up the high dollar products as though they are a cure all that works 100% of the time,whether it be heads,a cool popular name cam-shaft,intake, or what ever. Example? How many guys have put massive cams,heads or a Vic.junior on just to find out that performance has suffered. But how,why, when everyone swears by them? I see that mentality on here sometimes and I was just trying to make a point that unless you want to run a very fast rod, there are many factory products that will run fast at a fraction of the cost. We get so caught up bragging about our high dollar pro-stock cars that we spit on stock eliminator. A $1000 14 sec. brackett motor is just as important as a $50,000+ Pro motor when it comes to keeping the sport alive. Must be nice to have the money you guys have that disagree with me!

Originally posted by shevy not heme
Erik,no, I'm just trying to get some people out of the mentality that says that it has to be bigger to be better. Fact is,these heads have 80,000 miles on them with no cracks or serious problems at all. A good valve job and they will flow plenty good enough to get me in the 14's. Here's my point,if these 'junk' heads will do what I want, then somebody tell me why I should put $600 or more in a better flowing head if I don't need to? Can't get 14's out of 305 heads??? Sure you can. If I can run these junk,disrespectful heads and get a consistant 14 sec. 'bracket' racer why should I feel bad when I send guys trailor loading that have $2000+ heads on 10 & 11 sec. cars?
And come to think of it,if only the high dollar,fastest cars are the only one's to deserve respect then only top fuel cars should be allowed in the NHRA. But as I recall,I think there are still several classes/catagories. Isn't this what the different classes are all about?
Our American mentality gets the best of us sometimes. Bigger,better,more expensive, or it is trash? There has been quite a few 14,15,16 sec. brackett cars take the trophy home running 'junk' and we break far less parts.
Erik,pistons can be installed backwards,add 10hp,& not be noisy.

Pistons can be installed backwards and add 10 h.p. and not be noisy.Who in the world told you this?Why would you even try this?How or why would it make more h.p.?Here is a thought.The next time I buy a $700 set of buckets for one of my race engines I am going to install them backwards.I think not!!Don't you think the engineers that designed the pistons knew what they where doing?Why even try to second guess them?

Originally posted by shevy not heme
Bill,Techinspector,other replies, I wasn't bragging up 305 heads, I was defending the rap that they won't work on a mild build up with the right combination of parts,when race heads are not needed. Actually if someone had the money and was building an all out drag car, heads would be at the top of my list, right behind traction/suspension. Thats the place to start,or perhaps the place to put the money.
I read the posts, I have the mag. subscriptions,I have bought the products,the right ones and the wrong ones at times. All the talk is around high dollar,top of the line products,which I agree with as long as it is the 'right' combination. However,,,there are many of us that don't have the money or the desire to compete with the big boys. Neither am I saying that something like 305 heads is a place to start, not at all. What I am saying is that too many brag up the high dollar products as though they are a cure all that works 100% of the time,whether it be heads,a cool popular name cam-shaft,intake, or what ever. Example? How many guys have put massive cams,heads or a Vic.junior on just to find out that performance has suffered. But how,why, when everyone swears by them? I see that mentality on here sometimes and I was just trying to make a point that unless you want to run a very fast rod, there are many factory products that will run fast at a fraction of the cost. We get so caught up bragging about our high dollar pro-stock cars that we spit on stock eliminator. A $1000 14 sec. brackett motor is just as important as a $50,000+ Pro motor when it comes to keeping the sport alive. Must be nice to have the money you guys have that disagree with me!

if you have 350 heads, they will flow better than the 305 heads, the only benefit of 305 heads are the 58cc chambers, allowing for a higher compression than with a smaller 64cc 350 head, it will give you a slight gain in the low end over a stock 64cc head, because of the diffrence in compression, but they will choke on the high end

eric, please read this blurb from HPC Research.....

Take a Vice. Most any vice. Install a protective covering over the teeth of the Vice. Push wrist pin out of Piston until 2/3 of the wrist pin is sticking out. Stick the section that's sticking out into the covered jaws of the vice. Snug jaws of Vice around Wrist pin. Place one "leg" of a Carpenter's Square or equivalent on the table where the Vice is. Place the other "leg" of the Square up against the side of the Piston. (Adjust the Piston if necessary). Without moving the Square, Rotate the piston until the OTHER side of the Piston is facing the Square. Note that there is now a noticeable "gap" between the leg of the Square and the Piston. That "gap" is a measure of the "offset". (Actually, the gap is TWICE the wrist pin "offset", and it is left to the Student to prove why this is so.) Oh, so when you rotated the Piston, the Piston moved the Square back a little? No problem. Line the Square up again against the side of the Piston. Then Rotate the piston until the other side of the Piston is facing the Square. NOW, note the "gap". When you see the "gap", that side of the Piston is the one where the Wrist Pin is closest. (Think of the "offset" as increasing or decreasing the angle of the "lever" arm of the Connecting Rod on the Crankshaft. (Some Formula V racers purposely put their VW pistons in backwards- to INCREASE the Lever arm and Torque- piston slap be damned- especially if you win the race.) A Tip o' the Maestro's Hat to Mr. Stoddard for this simple but effective, handy-dandy little homemade tool to measure piston "offset".

(The diagram didn't come out right, but all it entails is using a carpenter's square stood on edge and up against the skirt with a reference on the table for the square to butt against.)

Originally posted by firebird77clone
it's all about flow and chamber size. The chamber size will have the final say on your compression ratio, and the valve size will determine your flow. You want the two-oh-twos valves for max flow, and then some mild grinding to unshroud them ( but don't enlarge the chamber too much ). Pretty basic stuff. Get a 350 build book, there are plenty out there to choose from and they pretty much have all the same information, wheras the 350 is the most common motor to build.

Peronally, I haven't made the leap to aluminum heads yet, but I can see it in the distant future. Money on your heads is money well spent, provided the chamber size is right for what you want. The heads and cam gotta be matched up, else it will be a dog.

I will have to disagree with this just slightly. It is not valve size alone that makes a set of heads good or bad, the port size is the other half of it. Look at the L31 Vortech heads with the 1.94" / 1.50" valves. They'll outflow any other pre-'87 Chevy head that has 2.02" / 1.60" valves.

I don't get it. If you have allready decided to use 305 heads, then why even bother asking the question????? Use them.

And it's not only port size, it's also the port shape that counts, especially in low RPMs, where you need high port velocity.
305 heads will bolt on and run on a 350. They will starve it out by about 4000 Revs, no matter what cam you put in it.
Any junkyard 350 head in good shape with a 64cc Chamber will outperform every stock 305 heads (ON A 350!!) and might cost as much as $50.
Bigger valves aren't always better. In small chamber heads the bigger valves are more shrouded, either you want to get rid of this shrouding or you stay with smaller valves and go for better-flowing seats.
350 heads are made for 350 engines and 305s for 305s respectively. If there were any gains to be had from using small volume, small chamber heads on a 350, then Chevy-techs would have come up with it.
I'm not trying to put you off trying things that nobody else has tried before, but there are many things that haven't been tried FOR GOOD REASONS
Just my opinion,
Max

I have tried using 305 heads,that's why I said to stop all the pre- ignition you're going to get you will have to open up the chambers to match the bore. I have built claimer engines which have to run stock 2bbl manifolds,and I work more with port velocity than volume. Yes flopping the pistons does increase the TDC squish,and therefore adds power,but at the cost of much more rapid piston and cylinder wear. I save a lot of money by getting engines from the small block modified guys over at the dirt track that can no longer be freshened back to 358 cu in. Lose your idea that everyone else has deeper pockets than you,or likes to piss away pay checks on billet dipsticks guaranteed to make 500 hp. Most of us out here are in hock for a house,and a family to feed.

Originally posted by techinspector1
eric, please read this blurb from HPC Research.....

Take a Vice. Most any vice. Install a protective covering over the teeth of the Vice. Push wrist pin out of Piston until 2/3 of the wrist pin is sticking out. Stick the section that's sticking out into the covered jaws of the vice. Snug jaws of Vice around Wrist pin. Place one "leg" of a Carpenter's Square or equivalent on the table where the Vice is. Place the other "leg" of the Square up against the side of the Piston. (Adjust the Piston if necessary). Without moving the Square, Rotate the piston until the OTHER side of the Piston is facing the Square. Note that there is now a noticeable "gap" between the leg of the Square and the Piston. That "gap" is a measure of the "offset". (Actually, the gap is TWICE the wrist pin "offset", and it is left to the Student to prove why this is so.) Oh, so when you rotated the Piston, the Piston moved the Square back a little? No problem. Line the Square up again against the side of the Piston. Then Rotate the piston until the other side of the Piston is facing the Square. NOW, note the "gap". When you see the "gap", that side of the Piston is the one where the Wrist Pin is closest. (Think of the "offset" as increasing or decreasing the angle of the "lever" arm of the Connecting Rod on the Crankshaft. (Some Formula V racers purposely put their VW pistons in backwards- to INCREASE the Lever arm and Torque- piston slap be damned- especially if you win the race.) A Tip o' the Maestro's Hat to Mr. Stoddard for this simple but effective, handy-dandy little homemade tool to measure piston "offset".

(The diagram didn't come out right, but all it entails is using a carpenter's square stood on edge and up against the skirt with a reference on the table for the square to butt against.)

Very interesting article but the dome design dictates what way the piston is installed for my application.This might be possible for a blown or turbo application when a flat top or dish piston is used.You might have to do some extra fly cutting on the piston to make this work.

interesting post... i have a set of what i believe are 305 heads *checked the casting number and thats what it showed* on my 350 that apparently have some serious machine work done to them, they are 2.02/1.6 valves, 64cc chambers, swapped them with my old set of stock 350 1.94/1.74 76cc heads.... and there is quite the performance jump with my my new heads.... or maybe im dreaming??? lol... but im just a young buck anyhow... and havn't dyno'd the car or raced it yet, but i do beat on it quite a bit and it damn near pulls the front end.... but again... who knows...

"it damn near pulls the front end."

You almost had me convinced about those 305 heads until you said that