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Old 02-02-2013, 05:59 PM   #1
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Default first rebuild 305 help

hi my name is mike irun prolly 3 to 5 county fair demo derbys a year i usually run whats in the car i am for the most part mechanically inclined done alot of motor swaps bought used performance engines but they dont usually last i wanna build my first motor to keep cost down its a 305 i am looking for info as far as best way to go mild build an power i need full spec from crank to rockers its an early 80s block i possibly would bore 30 over but i dont have the knowledge to choose good number valve size lift duration ect ect so if someone has a combo that works or stroke out to 331 i herd was possible please give me the specs thanks
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Old 02-03-2013, 11:20 AM   #2
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no body builds those because by the time you buy the parts to make it better you could just get a 350 to start with and have more displacement. you can find a cheap 350 from the 80'* tons of places and just get different heads, intake, cam etc. you will end up with more power for the same money. i have a 305 in my junk pile out back because i couldnt sell it for more than scrap value
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Old 02-03-2013, 10:05 PM   #3
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Ditto with jwfirebird, I'd start with a 350 vs a 305 if you want some power. I'm more into the new LS style engines than the old smallblocks when it comes to performance. But I know you can take a 350 and knock it out to a 355 or stroke it to a 383, add a good cam and some higher compression heads and you'll have a pretty good powerplant.
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Old 02-04-2013, 08:12 PM   #4
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i started coming to that conclusion after i posted i thanks for the info u 2 got a complete set of specs (crank to rockers) to get maybe 420 to 450hp with a budget in mind self built will have professional machine servicing while staying in the 1800 range i have the block
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Old 02-04-2013, 08:14 PM   #5
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while keeping the heads an block cast iron
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Old 02-05-2013, 07:33 AM   #6
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an ls maybe the better way then shaun would be better at that then me im a old school builder. but you arent doing anything with the 305 for those $ and hp. but if you scored a decent 5.3 or 6.0 steel truck vortec block for 3 hundred or so then you would spend the rest making it go with a aftermarket ign and they make a carb intake or you would have to get hptuners to tune the fuel injection and ign. but that way would easily be 450-500hp. thats what im making with my "pre 86" SB 350 but i got at least twice that into it. heads are where your power is at and cam and everything follows, you would have over 1k in just heads
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Old 02-11-2013, 12:28 PM   #7
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There are tons of articles on the web on 305'*.
This is a good article on 305:
305 Chevy Engine Blocks - Engine Masters Magazine
and:
HOT ROD'* 400hp 305
Even though I also agree that a 350 is a better starting point, if you already bought the 305 there are options.
My first question is how much are you willing to spend on the 305 build?
Some of the first folks really to have discussions with are engine builders. You are going to need boring,deck,porting etc.
My last 305 build was flat top pistons,30 over, Crane cam, roller rockers, ported,headers,edelbrock intake & carb 4 barrel,fluid harmonic balancer, Accel hei coil, and the distributor was re-curved on a sun pro distributor machine,w/variable vacuum advance, thst really woke it up.
Never had it on dino, but lets put it this way, no problem getting tires lit.
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Old 02-11-2013, 12:56 PM   #8
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havent heard that term in a while, distributor machine.

like i said though the key to any pre 86 sbc build is heads. without changing them you just spent a ton on making a 305 into about a stock 350 power wise.
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Old 02-11-2013, 01:08 PM   #9
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Here is a good article on Hei timing is everything...without SunPro Dist. Machine.
The Sun Pro machine if you can find some one who has one, allows spring changes etc and easily shows curve relative to rpm while distributor is mounted to the machine. It is a much more accurate way of testing and adjusting the final curve with variable vacuum advance.
I had my 305 set with base timing of 12 degrees advance, after re curve.
http://temp.corvetteforum.net/c3/joe..._Recurve.shtml
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Old 02-11-2013, 01:18 PM   #10
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the last time i saw one was in the garage of a guy we used to call his house the mopar museum. he had all the old tools and such in his garage and the memorabilia. dont get to hang out with him anymore he moved to detroit.


you dont see stock hei'* too much at the track, mine firebird has an aftermarket everything.
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