305 Vs. 350 - Team Camaro Tech
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post #1 of 9 (permalink) Old Dec 2nd, 05, 10:04 AM Thread Starter
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305 Vs. 350

What is the difference in horsepower, and what are some options to give a 305 more hp.
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post #2 of 9 (permalink) Old Dec 2nd, 05, 10:47 AM
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Re: 305 Vs. 350

First off - WELCOME to Team Camaro

The difference in HP varied over the years for the 305 v.s. the 350 - anywhere from @10 ~45.
The biggest drawback for the 305 has always been its small bore size (3.736") which prevents using larger valve sizes due to the shrouding of the valves and the limited overbore capability of these blocks. These were small CI 2bbl V-8's in all the early confiqurations, used as the base V-8 in almost all applications.
The upsides - if there are any , is that they shared the same stroke (3.480") and many internal parts from the 350, so replacement stuff is easy to find.
The later production 305 (5.0L) engines with TPI are fairly easy to modify to get a decent street crusing engine - but, you are still money ahead to just start with a 350 and build from there unless you are really interested in moderate HP output and higher fuel milage for a street car.
I've never seen a really highly built 305 in anything other than a LSR vehicle. I can't think of a single performance article specifically trying to build a 305 to have anywhere near the power to CI ratio of a 350 recently* - I'm probably wrong and hopefully someone will respond with the feature article I missed...
(* - I've seen a few 'it what's in the vehicle, so let's run with it' type articles...none of them were all out - how much can we get outta this sucker! )

Hope others that may favor these little mice will chime-in;
John

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post #3 of 9 (permalink) Old Dec 2nd, 05, 03:12 PM
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Re: 305 Vs. 350

If you have a choice, just get a 350. The money you spend chasing power with a 305 will buy you a 350 with lots more power. The 305 just isn't gonna be worth building up IMHO........................

Dave F. in Rhode Island
'68 Camaro SS Accel DFI 454 (SOLD - I'm a boring Corvette owner now)
Bought my first big-block Chevy in 1970
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post #4 of 9 (permalink) Old Dec 2nd, 05, 03:48 PM
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Re: 305 Vs. 350

I had a 305 in my 80 Camaro that was built with forged flat top TRW pistons .030 over with a Crane cam and aluminum Corvette 58cc heads with stock 350 valves, Edelbrock carb and manifold that would surprise many people but honestly, 350 is way to go for same money mo power.

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post #5 of 9 (permalink) Old Dec 2nd, 05, 07:57 PM Thread Starter
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Re: 305 Vs. 350

Thanks for the help i was leaning towards the 350 as well, but the car was purchased with the 305 in it and didn't know if it was worth it to purchase a 350.
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post #6 of 9 (permalink) Old Dec 5th, 05, 01:57 PM
 
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Re: 305 Vs. 350

Quote:
Originally Posted by Chevy-SS
If you have a choice, just get a 350. The money you spend chasing power with a 305 will buy you a 350 with lots more power. The 305 just isn't gonna be worth building up IMHO........................
my son and I bought a 1988 Iroc Z 28 stick with a 350 (5.1 L) recently installed up from a small block. It hesitates like mad and will nor pass smog. We heard that for that year, only the automatics were offered with the big block option. We have heard of a 'burned chip' that can be installed to let the computer 'read' the signals from the big block systems. Do you know if this is true...if so, do you know where we can buy one? Thanks lost in Cali
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post #7 of 9 (permalink) Old Dec 5th, 05, 02:01 PM
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Re: 305 Vs. 350

a 350 is not a big block. It's still a small block.

Christropher

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post #8 of 9 (permalink) Old Dec 6th, 05, 08:47 AM
 
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Re: 305 Vs. 350

and 350 heads do not properly mount on a 305. i forgot where its off , but it is somwhere by a few thousandths. they do bolt on but i think its the combustion chamber that willbe off a tad and can cause premature head gasket leak. I think i remember reading that in popular hot rodding or hot rod about 10 or 12 years ago when they did some 305 build for god only knows why.

U can get a 350 crate motor from summit or jegs starting cheap , complete intake to pan. i think summits is 1700 and change and jegs is 1300 and change for the Gmgoodwrench 350 cid 260 horse and they go up from there. going to swap meets or searching the net for a decent set of heads a used intake and carb , u could probly come out with close to a 400 horse sbc for about 2500 bucks if you are thrifty and can do the work yourself.
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post #9 of 9 (permalink) Old Dec 6th, 05, 09:49 AM
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Re: 305 Vs. 350

Quote:
Originally Posted by ddymichael
..."It hesitates like mad and will nor pass smog.
We heard that for that year, only the automatics were offered with the big block option. Do you know if this is true...
Thanks lost in Cali
'ddy';
The hesitation and not passing smog may very well be due to a incorrect PROM program in the ECM. There are plenty of shops and sources for updated programs to make the engine perform as designed and desired. Look in some of the current Magazines on the sore shelves or do a web search for 'engine controls, eproms, efi' and the like for some sources. You should come up with lots of links to explore. such as Arizona Speed and Marine.

While it is true that the 350 (which is still a "small block", as was previously stated...) was only offered with an 'auto trans' in 1988, there is usually no reason the state ( I take it your in Calif. - you should add that and other info to your profile - we like to know there are fellow Camaro-guys around...) will not certify your 'conversion/engine change' (NOTE: take notice of those words - and ONLY use them when talking to a state smog referee - they HATE to hear other 'swap words'... )
You can normally get an engine change approved in the state if you used an engine available in that model and of the same manufacturer without to many new 'hoops' to jump through - getting the tail-pipe passed the inictial "sniffer test" is the first step to getting the car back into good graces with the smog-folks.

(edit) We would need to know much more about the "change" to advise further. You might want to start a new thread with more specifics so we can help you out best.( Okay - belay that last request...:O just looked through 'todays' posts after searching 'subscrbed threads' and found your questions. We're going to lose our power here for some line work in a couple minutes , so I'll have to respond tonight or later today...)

John

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Last edited by Vintage 68; Dec 6th, 05 at 10:01 AM.
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