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I am overhauling a 1974 sb chevy 350 4 bolt mains.
It just have 150 hp that year,what stock cast iron heads would work on this to raise compression to around 9 to 1.
this is not a race engine, it is in a 51 mercury. driven on street.
what else did gm they do to it to come from around 287 hp to 150 hp?
this is a low buck build
 

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they went from leaded to unleaded gasoline, and under there current technology and research had to go from 10.5-11.5:1 engines to 8.0:1 engines and in turn also took the lift and durations out of the cams, takeing the power down to horrible #'s, you should look for a set of chevy vortec heads 062's are the best as they have a better exhaust seat and allow better flow, but the 906's are a very good head to they are 64cc instead of 76cc combustion chamber this alone will raise you compression ration up by a full point getting you to that 9.0:1 number your looking for, they also have a larger int valve, and runners to increase flow, these head are one of gm's best flowing production heads ever made for the sbc, you will need to run a vortec style intake but im sure you could find a decent performer/or perf rpm intake with the vortec bolt pattern on craigslist or e-bay for cheap, then buy a 600-650 cfm carb, a mild cam, and you will increase hp/tq#'s by at least 100
 

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throw a pair of 305 heads on it. preferably casting #14014416. These were produce from 1980 to 86(?). Should bring you up to almost if not more than 10:1 compression. Should be able to get them at a decent price from the junkyard. a lot of the k10 pickups from those years had 305s. Theres a few on ebay as well. just search the casting number. Heres a link to one pair of rebuilt ones, theyre about $350 including shipping, but there are a couple pairs on there that probably need rebuilt but theyre asking $50 buy it now. Main problem with those is theyre local pickup only, but maybe youre close! Anyway, the 305 heads have a 58cc chamber. thats probably you're best best without spending big bucks on high performance aluminum heads.
You could also go with a set of vortec heads. a brand new pair is $600. wouldnt help compression a lot, as they have a 64cc chamber, but they seem to improve power quite a bit. keep in mind if you go that route you'd also have to buy a vortec intake. so long story short, cheap improvement = 305 heads, more expensive, improvement = 350 vortec heads + vortec intake + port / polish. Then top either setup off with an edelbrock performer carb. 650 or 700cfm. you'll have a pretty decent setup. Should give you a decent power boost. Have fun!
 

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klutchmaster427 said:
throw a pair of 305 heads on it. preferably casting #14014416. These were produce from 1980 to 86(?). Should bring you up to almost if not more than 10:1 compression. Should be able to get them at a decent price from the junkyard. a lot of the k10 pickups from those years had 305s. Theres a few on ebay as well. just search the casting number. Heres a link to one pair of rebuilt ones, theyre about $350 including shipping, but there are a couple pairs on there that probably need rebuilt but theyre asking $50 buy it now. Main problem with those is theyre local pickup only, but maybe youre close! Anyway, the 305 heads have a 58cc chamber. thats probably you're best best without spending big bucks on high performance aluminum heads.
You could also go with a set of vortec heads. a brand new pair is $600. wouldnt help compression a lot, as they have a 64cc chamber, but they seem to improve power quite a bit. keep in mind if you go that route you'd also have to buy a vortec intake. so long story short, cheap improvement = 305 heads, more expensive, improvement = 350 vortec heads + vortec intake + port / polish. Then top either setup off with an edelbrock performer carb. 650 or 700cfm. you'll have a pretty decent setup. Should give you a decent power boost. Have fun!

:rolleyes:

yes the 416 head are a decent head but to get anywhere near the performance of a vortec you would need change the int valve as it is only a 1.84 not a 1.94, the you would need to port and polish them and now you are talking $$$, you can look on e-bay or craigslist for a set or rebuilt vortecs, i just found some in dallas for 360.00 from a guy who does it for living, if you look you will be able to find them, and they are far and beyond more worth it then the 416's, since you are running this on the street you dont want to run anymore than around 9.6:1 as when you get past that it gets much harder to tune the engine and to keep it tuned and you will also most deffinatly have to run high-test gas, plus colder plugs and possibly a cooler thermo to avoid detination, you should be staring off with about a 8.0-8.2:1 compression ratio, the 64cc heads would give you around 9.0-9.2:1 and the 58cc would give you around 9.6-9.8:1 compression ratio, vortecs are a far better head, and you can find the intakes used as well very easily, and there is nothing wrong with a used intake, and use either a 600-650 cfm carb not a 700, unless you plann on reving it a bunch past 6000rpm a 600 is plenty but a 650 is fine too
 

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my87Z said:
:rolleyes:

yes the 416 head are a decent head but to get anywhere near the performance of a vortec you would need change the int valve as it is only a 1.84 not a 1.94, the you would need to port and polish them and now you are talking $$$, you can look on e-bay or craigslist for a set or rebuilt vortecs, i just found some in dallas for 360.00 from a guy who does it for living, if you look you will be able to find them, and they are far and beyond more worth it then the 416's, since you are running this on the street you dont want to run anymore than around 9.6:1 as when you get past that it gets much harder to tune the engine and to keep it tuned and you will also most deffinatly have to run high-test gas, plus colder plugs and possibly a cooler thermo to avoid detination, you should be staring off with about a 8.0-8.2:1 compression ratio, the 64cc heads would give you around 9.0-9.2:1 and the 58cc would give you around 9.6-9.8:1 compression ratio, vortecs are a far better head, and you can find the intakes used as well very easily, and there is nothing wrong with a used intake, and use either a 600-650 cfm carb not a 700, unless you plann on reving it a bunch past 6000rpm a 600 is plenty but a 650 is fine too
You have a good point. I also didnt pay attention to him wanted it to be a daily driver kinda. rather than looking just for cheap power. the vortec is a great setup. Ive heard numerous times that rebuilders can rarely replicate the setup of a factory vortec head, and that its best to buy new ones. i think hot rod magazine did an article for a "cheap" 400hp 350. you might wanna check that out. they used vortec heads for it. ill post the link if i find it
 
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