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1977 Chevrolet LG3 305cid V8 motor

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1977 Chevrolet LG3 305cid V8 motor

camochrist camochrist
New User | Posts: 49 | Joined: 07/06
Posted: 07/24/06
12:41 PM

I recently received one of engines as a gift (?) and was wondering what to do with it.  Somebody fit some decent aftermarket speed parts on her at some point... Edelbrock performer intake manifold, Holley 'rochester" carb,  Hedman headers.  It was attached to the gift 55 Bel Air,  and it does ok in the mid range and higher power areas...

But I'm also hearing smack about it being just another smogger, and one which parts are getting expensive for.  So,  just tell me what you think,  don't hold back... I can take it.  As I said,  it was free,  I don't care if it just becomes a boat anchor.


hot_rod_mike hot_rod_mike
New User | Posts: 25 | Joined: 07/06
Posted: 07/24/06
02:28 PM

get rid of the heads dude you'd be better off with better heads like afr,or edelbrock rpm heads ..thoes heads that are in that eng are for smog wich kill hp ditch thoes heads or get a 350 your choice

youll do beter with a 350 you can use the intake and carb if you want .. the parts are interchangeable from  305-350



min301 min301
Enthusiast | Posts: 494 | Joined: 02/05
Posted: 07/24/06
07:05 PM

Mypersonal opinion is that it is only good for a running engine. No amount of speed part's will make it even close to as good as a 350. Ok for a driver, no good for performance.  
Just here to help,  
 Professional Automotive Technician, Engine Builder, and Ford guru.
Bill Voorhees

camochrist camochrist
New User | Posts: 49 | Joined: 07/06
Posted: 07/24/06
07:50 PM

Right... the 350 advice... here's the funny part: the former owner thought it WAS a 350!  'Cause who would add the shiney bits to an old 305?  You mention transfering parts from 305 to 350, how would the intake manifold mate up to a different block?  Aren't they different blocks?  Aren't they different cylinder heads?  Is the performer really interchangeable?  

camochrist camochrist
New User | Posts: 49 | Joined: 07/06
Posted: 07/24/06
07:54 PM

Let's say i keep the tiny 8... and get some better heads on it.  Heck, while we're at it we'll assume it gets a nice new cam too:  Am I looking at 200+ hp?  What kind of smallish Chevy product would I be looking to screw this into?  

AmericanMuscle13 AmericanMuscle13
Enthusiast | Posts: 581 | Joined: 01/07
Posted: 07/24/06
09:03 PM

Everything from the heads up on your 305 will bolt on to 283,302,307,327,350,and 400.  I believe the crank between a 305 and 350 will swap too.  My opinion unless you live in like India and can't come across a 350 block don't waste your time.  Hell I have one I'd probably sell you for 20 bucks if you came and got it.

Mitch "I'm a Mean Machine, Drinking Gasoline and Honey you can make my motor run"-Guns and Roses

User | Posts: 119 | Joined: 10/04
Posted: 07/26/06
04:19 AM

     I must agree with the 350 idea... 305's are o.k. for smaller lighter cars (torana, monza, etc..) but in your case the 350 would be a better choice. The 305 heads, inlet manifold, dizzy, oil pan, will swap straight on a 350. The crank should be a go, as well as the conrods. The 350 has more potential for power, due to larger bore. However if you are really stuck with the 305 for now, you can spice things up a bit with it, until you find a good 350. Better heads are in order as well as a cam suited to your rear end gearing and intended driving purposes. The performer is a great intake and will work on both the 305 and 350. Headers/extractors will also interchange. So you do have some options open for the smaller motor, in a pinch.  Good luck with your project!



Guru | Posts: 793 | Joined: 11/05
Posted: 07/27/06
03:03 PM

200HP is easy...tpi 305's got that...actually the later ones got 230HP.  But its really not worth it.  I'd strongly suggest the 350.  Like the other guys have said, pretty much everything will interchange...except pistons obviously.  You should be able to pick up a 350 for cheap and would have a considerably stronger starting point.  I have a 305 TPI in my camaro and did a bunch of stupid stuff like an adjustable borla cat back exhaust, high flow catalytic converter, edelbrock headers, milled the heads, matched them to the intake, had a 3 angle valve job done, increased fuel pressure, advanced timing from stock...never noticed any difference (it was in good running order since to get it there I had to replace every sensor on the car plus the computer).  My 305 has a roller cam in it and yours will not...another thing to consider.

Go with the 350.  For the cost of the heads and a cam you can get a running 350 easy.


Casey McCall:What happened to your values?
Dan Rydell: I find that maintaining them is a lot of work. I take a day off every now and then.
Casey McCall: You take a vacation from doing the right thing?
Dan Rydell: Yeah. I don't loot storefronts or anything, but once in a while, when I consider the effort it takes to diligently adhere to a moral compass, I take myself out of the lineup and I rest up for the next game.
Casey McCall: I swear, you could run for Congress and win.

tpimachine tpimachine
New User | Posts: 7 | Joined: 08/06
Posted: 08/03/06
06:18 PM

A 305 in a decent size car like a shoebox is just asking to be slow.  The only way you can make that 305 work for you is to spend a ton on cyl heads, a good size cam, stroke it, and tune it for days with an awesome gear and converter combo.


You could be just as fast with a 350 with a much smaller cam, stock heads and much less gear.  In the long run, it would cost about the same investing in a 350 block, but atleast people wont laugh at you for using that boatanchor 305.