Thread: 305 race engine?
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05-05-2005 06:03 PM #1
305 race engine?
first off 305's are junk and i shouldnt even post this but i gotta...the plan was to get a 350 from a impound lot my dad worked at but that fell through cuz he passed away and his bosses are being assholes so now im stuck with a 305(im not sure if ill waste my time)but i wanna build a race engine with the stock reciprocating rods and crank.stock heaviley ported heads and a 2200-5500 cam what else would work and wut would be better its crazy but i might have to do it with my very tight budget
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05-05-2005 09:59 PM #2
If you're gonna bolt a 305 together because of limited budget, o.k., but don't spend one red cent trying to port those turd heads. Run 'em like they are with a good valve job until you can afford some decent heads. Figure you exact compression ratio before you ever try to pick a cam. If you don't know how to figure it, see this paper I wrote....
http://streetmachinesoftablerock.com...opic.php?t=124
Here's a dyno-proven combination....
http://www.goingfaster.com/spo/325_h...chevrolet.htmlPLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.
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05-06-2005 11:06 AM #3
i got the heads resurfaced and deburred the inside of the engine...it needs to be bored to 4.000 but doin that and adding new pistons is probably just as much finding a cheap 350...i need new heads these are really crapy anyone have some vortecs?
thanks tech
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05-06-2005 12:12 PM #4
Autocity...bore it out to 4.00" ? um you cant bore it .265". the stock bore on a 305 is 3.735"...so to get 4.00" youd need to boreit .265"....your right...you shoulnt have started this thread75 GMC C-15 factory 454, automatic, lowered
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05-07-2005 05:59 AM #5
305
I know there's an advantage in cubic inches, but there's also an advantage in smaller displacements in being able to spend them quicker. Wouldn't you be able to spin a 305 faster than a 350 produce higher horsepower but less torque?
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05-07-2005 07:04 AM #6
Re: 305
Originally posted by firebird45331
I know there's an advantage in cubic inches, but there's also an advantage in smaller displacements in being able to spend them quicker. Wouldn't you be able to spin a 305 faster than a 350 produce higher horsepower but less torque?
Answer < NO > You have the same stroke in both. If there were even the slightest gain in rpm which I doubt, You are pissing up a rope.
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05-07-2005 12:38 PM #7
Fire, if it was a short stroke engine, like a 302 or 307, than yes, they can spin up quicker. The only rev factor that the 305 MAY have over a 350, is the fact that because the pistons are smaller...they are lighter, & also less ring friction....but its not enough to hardley mention....so ..in this case ..no.75 GMC C-15 factory 454, automatic, lowered
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05-07-2005 05:18 PM #8
that's what I was thinking of reciprocating mass. I knew the stroke was the same. That's what makes the 283's and 289's so cool
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05-07-2005 05:21 PM #9
Hi RPM motors are kewl, but they have their quirks, Narrow power band, etc. (Ok Scooter, you can jump in now!!!) I prefer big cubes, big torque, and lower RPM.. JMOYesterday is history, tomorrow is a mystery, Live for Today!
Carroll Shelby
Learning must be difficult for those who already know it all!!!!
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05-07-2005 05:24 PM #10
not that ricers are in anyway cool, but they can spin the hell out of their motors and sound like pissed off weedeaters while still have crap for torque and still spend 7 times as much to do it.
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05-07-2005 07:28 PM #11
torque is really important coming off a turn.RPM dont have anything to do with the diff of a 350 and 305 its the pistons heads and cam "soft cam" but since im changeing all that ecept the heads and getting it borred to 4.000 its like a 350 with a crapy 2 bolt main.i have a ? is it normal for a crank to rub against the main caps and block im not sure? whats wrong with racers firbird?we got just as good of cars as you do just a little modified and i have a semi hot rod to 76 camero so im not just a race car driver
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05-07-2005 07:44 PM #12
autocityman4, didn't you read stepside454's answer to this. You CANNOT bore a 305 block to 4.000"PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.
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05-07-2005 07:53 PM #13
yes the bore allows like .30 over and i know someone who does the odd bore sizing
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05-07-2005 07:56 PM #14
Originally posted by autocityman4
yes the bore allows like .30 over and i know someone who does the odd bore sizingPLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.
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05-07-2005 07:59 PM #15
i dont meen allows it but a 305 can be bored that large not a safe thing but it can be done
Welcome to CHR. I think that you need to hook up your vacuum advance. At part throttle when cruising you have less air and fuel in each cylinder, and the air-fuel mixture is not as densely packed...
MSD 8360 distributor vacuum advance