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Old 10-01-2008, 01:18 PM
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grabit Building up a gm 305

     

I am not sure how many of you are gm motor heads,but I figured Id give it a shot.
I am going to be building this HO 305 out of a 85' caprice and put it in like a 2nd or 3rd Gen camaro.Where should I start?The motor runs very good and only has 61,000 miles so getting rid of a good low mile motor would be stupid.It already has a 4-barrel on it,not sure if that makes any diff.I read on another forum that if I got some better flowing heads and valve train,cam,HC pistons off set ground the crank 3.39" and bored .030 over it would be basically a quick little 302 from back in the day.
I also thought of building it up to support a supercharger,it would probably be just as much work and I could get a used supercharger for a good price,plus it would be faster.
This is ganna be my first build and my dads a body man so he can paint it any color I want,I am in no hurry to finish it and if it is ganna cost me more then I suspected then I will just drag it out longer.This is ganna be a father son project so there is no deadline.
Any insight is appreciated

Last edited by ktm_cody_199; 10-01-2008 at 01:29 PM.
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Old 10-01-2008, 02:11 PM
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No offense but you would probably be better off selling that 305 and picking up a 350 4 bolt main block. You need to decide if you are going hi comp or with a supercharger because doing both without spending 20k usually ends up with a lot of blown money. If you do keep that motor though, get a set of Dart heads with crane roller rockers and go with a roller cam. Make sure that you do not use junk pistons like TRW or Keith Black. Go with great forged Arias, or JE pistons. I also recomend forged steel rods and not alluminum. Remember when building an engine go with forged everything and cast or billett nothing since forging provides a grain flow. Also make sure they are not multiple press forgings also (TRW and KB) pistons. Your weakest weak will be your bottom end though, and with that motor theres not much you can do about it.
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Old 10-01-2008, 02:22 PM
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What do you think the motor's worth?Not sure what the tranny is but I do know it is a four speed auto.Will 350 or 327 internals fit in it?
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Old 10-01-2008, 02:25 PM
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If I put a good bottom in it, HC pistons, a better valve train and some porting will it hold up under boost?What should I put on it for a carb if I do go the blown route,holley or edelbrock?Could I put maybe a 283 crank with spacers in it? and go the 302 route.I am looking to build a high revving/high HP motor.
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Old 10-01-2008, 02:27 PM
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We've got an old Caprice cop car with a 350 in it. I think we're going to rebuild it and put it in my truck.
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Old 10-01-2008, 02:30 PM
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Quote:
Originally Posted by jhendrix View Post
We've got an old Caprice cop car with a 350 in it. I think we're going to rebuild it and put it in my truck.
There you go
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Old 10-01-2008, 02:35 PM
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Dump the 305. Go with a 383 stroker or a 350. How long do you want it to last is the question you need to ask yourself. Mine lasted about 15,000 miles and it was done. 11 1/2:1 compression. We had 194 heads and ground them out to 202's. 336 duration with a 556 lift on the cam. steel crank, roller rockers, triple valve springs. high volume oil pump, I also ran a duel point on it. I was going to go HEI, but I had the duel set up, so I went with it. I perfer HEI anyday. If your thinking a blower, better run down in the 8's on compression. That will in turn give you more boost and last awhile longer. Oh yea, and just because someone says they got a big 750cfm double pumper don't mean nuttin. I tryed the 750 on mine. Ended up with a 625 carter with 68's in it to make it run right. Bigger is not always better bud.
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Old 10-01-2008, 02:41 PM
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So,sell the 305 and get a 350.What is the 305 good for if I cant sell it?
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Old 10-01-2008, 03:16 PM
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Quote:
Originally Posted by Freak View Post
Dump the 305.If your thinking a blower, better run down in the 8's on compression. That will in turn give you more boost and last awhile longer. Oh yea, and just because someone says they got a big 750cfm double pumper don't mean nuttin. I tryed the 750 on mine. Ended up with a 625 carter with 68's in it to make it run right. Bigger is not always better bud.
Blown sounds alot less work and more relible then a decked out High comp,high lift motor.What do I have to do to build my little 305 to support boost.I really would like to utilize the motor because I dont have the heart to junk it and I dont think anyone will buy it,plus it will save some money.What type of cam should I run with a blower?I know Holley makes a supercharger specific car but I dont know if theyre any good.How big of a carb should I use on a blown 305?I probably sound stupid building a 305
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Old 10-01-2008, 03:26 PM
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If you want to stick with that 305, punch it out 30 over and add a mild cam. It will last for ever, and you won't spend a ton of money on it. Building the small block chevs are easy. So many parts out there. Honestly, the 4 bolt vs the 2 bolt does not jive with me. I know it's stronger, but honestly, when the last time you seen a main break?
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Old 10-01-2008, 03:56 PM
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Quote:
Originally Posted by Freak View Post
If you want to stick with that 305, punch it out 30 over and add a mild cam. It will last for ever, and you won't spend a ton of money on it. Building the small block chevs are easy. So many parts out there. Honestly, the 4 bolt vs the 2 bolt does not jive with me. I know it's stronger, but honestly, when the last time you seen a main break?
Ive never heard of a main cap breaking.How much horses you think I could get out of the little motor?Im looking to get around 400,this isnt going to be a daily driver,thats what my trucks for.This is ganna be my toy to pick on the little fart can rice racers all the rich kids at my school drive They seem to think that intake,ignition,exhaust,and bigger injectors is enough for a little civic or celica to smoke anything the us ever came up with
Wish I could find a 302 laying around in a junk yard
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Old 10-02-2008, 04:09 AM
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Quote:
Originally Posted by Freak View Post
Honestly, the 4 bolt vs the 2 bolt does not jive with me. I know it's stronger, but honestly, when the last time you seen a main break?
Not in a competition race car......twice but that is two times to many for me.
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Old 10-02-2008, 04:13 AM
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Quote:
Originally Posted by ktm_cody_199 View Post
Blown sounds alot less work and more relible then a decked out High comp,high lift motor.What do I have to do to build my little 305 to support boost.I really would like to utilize the motor because I dont have the heart to junk it and I dont think anyone will buy it,plus it will save some money.What type of cam should I run with a blower?I know Holley makes a supercharger specific car but I dont know if theyre any good.How big of a carb should I use on a blown 305?I probably sound stupid building a 305
100% wrong. If you supercharge it your going to have to build a stronger motor just with low compression and if you don't do the headwork you will use a supercharger at about 40% of what it could be.
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Old 10-02-2008, 04:21 AM
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No offense, but the 305 is one of GM biggest boat anchors. The block castings alone are horrible. Get a core 350 from a Salvage facility or from an individual:

Chevy 350 short block core
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Old 10-02-2008, 04:25 AM
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Quote:
Originally Posted by ktm_cody_199 View Post
Ive never heard of a main cap breaking.How much horses you think I could get out of the little motor?Im looking to get around 400,this isnt going to be a daily driver,thats what my trucks for.This is ganna be my toy to pick on the little fart can rice racers all the rich kids at my school drive They seem to think that intake,ignition,exhaust,and bigger injectors is enough for a little civic or celica to smoke anything the us ever came up with
Wish I could find a 302 laying around in a junk yard
I hate to be the bearer of bad news but unless you put about 10g's into your car a civic with those mods that you said is going to walk all over you. I am not an import pusher at all but I got stuck with a Honda that I bought for someone a bout 8 years ago so I decided to see what 3 grand would do and it was good enough to pull a 13.25(not bad for a honda) the one time I took it to the track. But the power to weight ratio that those kids are going to have on you with those slight mods will take you out. You're gunna need a 383 stroker to take em. With that said I have a 468 BBC without heads, never been put together that I would sell but shipping might be a bit high.
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Old 10-02-2008, 04:26 AM
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Quote:
Originally Posted by ktm_cody_199 View Post
Ive never heard of a main cap breaking:
You wont break a main cap usually, but you can get what is called main cap fret. And that can lead to a spun bearing and other problems.

http://www.landlinemag.com/archives/...rformance.html

Never never never skimp on the bottom end.
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Old 10-02-2008, 10:28 AM
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Quote:
Originally Posted by krzywhiteboy View Post
You're gunna need a 383 stroker to take em. With that said I have a 468 BBC without heads, never been put together that I would sell but shipping might be a bit high.
IMO A big block is to much for a little camaro, and even if I did want to put one in it shipping to FL from Cali is going to be crazy.I was thinking a built 327,I found a few cheap on ebay,everyone builds 350's and I would just have what the guy down the street put in his hot rod.So im down to a 383 stroker,or a tastefully modded 327.Which would be better,I was looking for something light that can rev to the moon and back hitting some high HP # but still make traction.
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Old 10-02-2008, 11:00 AM
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Here's what you need Cody, even comes in KTM orange

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Old 10-02-2008, 11:32 AM
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I cant see it what is it?
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Old 10-02-2008, 11:35 AM
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Quote:
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I cant see it what is it?
It went that quick it's gone!
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