Thread: 305 heads junk?

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Why can't you use 305 heads on a 350 mild drag only car with a high octane mix and a cam duration to match? All I won't to do is run consistant 14's. All other engine mod's will be matched to these heads,pistons,intake,etc. All I hear is that it won't work,why not if I match octane and cam and don't want a car any quicker than 14's? Anyone ever try this? And yes,,,before someone lectures,,,,I know full well that higher flowing,bigger valve heads would offer benefits but if the 305 heads are the ones I want to use then that means,,,,I want to use 305 heads! They just won't work on a 350 or will they? Talking bigger,better,more expensive is not the only way to skin a cat. Point is,I would like to build something that is 'not' a top fuel dragster,not expensive, and would like to see more subjects about 'tricks of the trade' speed secrets on here other than more cubic inches,hell,everyone knows that. How about if I install the pistons backwards,is it worth anything? Any 'old school' stock class veterans on here with some class tricks to share? I really get sick of the cubic in's.,nos,trick cams,and the high buck sells promotions that fool the youngins out of their money.

.....probably the MOST important thing in an engine build up is the heads. I once talked to a major engine builder about building a 305 that I had {it was stock except for a 'chip'}. I wanted to put a cam in it. He said that to do a cam without heads was almost a waist of money. So if it's a waist of money to put a cam in a stock 305 without also doing the heads I certainly WOULDN'T use 305 heads on a 350 drag car. just my opinion..... Bill

Ps, Just rethinking on my answer; what does your car weigh? or what kind of car is it? I went to campbellenterprises.com, they have a place where you put in the weight of your car & it tells you what HP you need. Check it out. Mid 14's are probably possible. Exspecially in a light car, or add nitrous.... It's just that the 'weak link' will definately be the heads......

"I really get sick of the cubic in's.,nos,trick cams,and the high buck sells promotions that fool the youngins out of their money."

I can assure that nobody on this board is attempting to "fool the youngins out of their money". You probably see the same old answers to the same old questions because those of us who answer have been doing this for decades and we know what works and what does not.

If you want to try to re-invent the wheel by using 305 heads on a 350, knock yourself out. Yes, they bolt on.

Another thing, I am not trying to belittle you in any way, but they are spelled Chevy and Hemi, not shevy and heme.

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.

Old school is camel hump heads.
Fool school is 305 heads on 350.

You'd be better off angle milling your stock 350 heads and intake to match. 305 heads slow down a 305, what you think they do to a 350.

The stock 350 heads should be able to turn 14's with a mild cam unless you got it in a land barge.

Originally posted by shevy not heme
Why can't you use 305 heads on a 350 mild drag only car with a high octane mix and a cam duration to match? All I won't to do is run consistant 14's. All other engine mod's will be matched to these heads,pistons,intake,etc. All I hear is that it won't work,why not if I match octane and cam and don't want a car any quicker than 14's? Anyone ever try this? And yes,,,before someone lectures,,,,I know full well that higher flowing,bigger valve heads would offer benefits but if the 305 heads are the ones I want to use then that means,,,,I want to use 305 heads! They just won't work on a 350 or will they? Talking bigger,better,more expensive is not the only way to skin a cat. Point is,I would like to build something that is 'not' a top fuel dragster,not expensive, and would like to see more subjects about 'tricks of the trade' speed secrets on here other than more cubic inches,hell,everyone knows that. How about if I install the pistons backwards,is it worth anything? Any 'old school' stock class veterans on here with some class tricks to share? I really get sick of the cubic in's.,nos,trick cams,and the high buck sells promotions that fool the youngins out of their money.

The 305 heads are very prone to cracks.The 305 heads also use a very small combustion chamber that "shrouds" the valves.If you install the pistons backwards you might not even beable to turn the engine over thus getting rid of your side to side rod clearance.Also some pistons have the valve relief's cut only on one side.If they where put in backwards the valves might hit the pistons.Are you just messing with us?

My old humps on my 283 were not doing to well with the original setup, they had a big solid cam and still had points. I had a set of completely worked 305 heads so i put them on along with a 480 hyd cam, electronic ign steert dom intake and a new 650 edlbrock. It runs better than I expected around 7,000 rpm's.
On the other hand a knew a guy that had 305 heads on his old 350 nova and all he good get was 5000 rpm, when he put the cammel humps on it gave it much more power and 6000 rpm's.

Nobody is saying you can't, just warning you not to bother. Yeah,you can lay a 350 head gasket on the suface,scribe all the chambers,and then grind off the material that sticks out beyond the bore.this will help stop all the pre ignition,and lower the compression back down, now after all that grinding,you've only got to overcome small ports and valves,and the fact these heads are prone to cracking,are you starting to get the point?

.....Chevy not hemi mentioned in a previous post about having a set of 305 heads {58cc, 1.84 / 1.5 valves} & a set of 350 heads {76cc, 1.94 / 1.5 valves}. I don't remember the exact wording but the only person to reply told him to use the 305 heads to raise the compression & then rework them to hold the 350 valves. May be this is where he got the idea??? bill

I am not saying use the 305 heads at all, only reason I used them is because a guy had spent 400 buck reworking, shaving and putting new springs, then wrecked the truck and and gave me the heads. I am going to run them until I rat hole enough money to get some better heads for myself. Either work the humps or buy some new. Here about a year ago I hauled all my spare 305 parts to the scap iron yard, I don't think I could ever bring myself to spend money on a 305 setup.

Originally posted by chevydrivin
I am not saying use the 305 heads at all, only reason I used them is because a guy had spent 400 buck reworking, shaving and putting new springs, then wrecked the truck and and gave me the heads. I am going to run them until I rat hole enough money to get some better heads for myself. Either work the humps or buy some new. Here about a year ago I hauled all my spare 305 parts to the scap iron yard, I don't think I could ever bring myself to spend money on a 305 setup.

NO, NO not you!!! What I meant by 'previous post' was I did a search on Chevy not Hemi's posts. You know, I did a search to see what kind of posts he'd done in the past. When Erik Erikson mentioned that may be he 'wasn't for real' I looked back to see if he was.... & he is..... Someone 3 months ago told him to do it. Looks like he has a S-10 that he's building. Just doesn't want to put that much money in it.....

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 are offset on the rod to keep them from being noisy. I can assure you that if you install them backward, they will be noisy.

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.

Oh my gosh, what am I going to do with you Chevy not Hemi??? And right after I made the statement "Chevy not Hemi is for real". Now I have ege all over my face! You stated "Your trying to get some people out of the mentality that bigger is better???". In other words your going to talk 'us' into using 305 heads instead of 350 heads on a 350??? You ALREADY OWN the 350 heads, why not use them??? You can do one of two things; a) use your 305 heads & run high 14's. or b) use your 350 heads & run low 14's. Sorry but your not going to talk me into 'giving up' a half a second in the quarter! And NO ONE said to "go buy $600 heads!!!". What everyone is saying is "USE THE 350 HEADS THAT YOU ALREADY OWN!!!". And now your saying "The 305 heads will do 14's" & "Sure you can go 14's with 305 heads!!!" IF YOU ALREADY KNEW THE ANSWER THEN WHY DID YOU ASK THE QUESTION???"You don't want advice, YOU WANT TO ARGUE!!!
love, Bill......

Originally posted by techinspector1
Pistons are offset on the rod to keep them from being noisy. I can assure you that if you install them backward, they will be noisy.

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