Seriously thinking about 305 upgrades

[bhw33191]

I've posted about this a long while back but i'm actually seeing this as a possibility. I know someone who can do it cheap. I figured i have an engine that works and if i can do it for cheap then why not do some mild yet effective upgrades? I'm up for the learning experience anyway, despite the bad reputation this motor has when it comes to response and power.

So what i want to know is what exactly should i do? I was thinking replace the carb, intake, and camshaft, but what exactly should i get? I remember Silicon or somebody else might have mentioned a specific cam i should use. I think whoever it was said i'd be happier with a mild cam? (I'm good with that economy-wise) but also a certain (mild) cam would ensure i don't actually lose power when it comes to low end torque, and this engine would be NOTHING without that. So what should i use for a new intake/carb setup? Would i be ok with the stock heads or even exhaust headers too? Like i said i think i want this to be a mild, yet noticable upgrade.

[J-Ri]

I believe the major reason these engines lack power is that the bore is too narrow to allow enough valve space for the length of the stroke. Intake and carb may help, but I don't think you'll get enough of a difference to justify the cost. Honestly, you'd probably be better off swapping in a salvaged 350 and leaving it stock.

[beat88ls]

quadrajet carbs may be disrespected but i would stick with the e4me. i may be wrong (please correct me if so) but i recall reading somewhere the e4me quadrajet flows 600+cfm. my buddy always had "toys" his first car was a 72 chevelle, his old man had a 56 chev belair with a m22 4speed and a 305 from a camaro. they dumped crazy money into the engine, cam, heads, complete low end and after all the work the engine was still lacking. they eventually dumped the 305 and picked up a 327... if you are willing to tear apart your engine and be without your car long enough to get it back together why not go with a 350?

[j cAT]

no way on a 305cu....waste of your money...

the 350 cu with the engine work can be do able and worth the effort, with results.

[wafrederick]

305s are worth nothing and most machine shops will tell you this.The Quadrajet carb,most peoplw walk away from and do not know they are very simple and easy to rebuild.If looking for a 350,lok into a good crate engine.Edlebrock,Jasper and GM have them with a warranty on them.Rebuilding an engine these days is not worth the time.

[2dooreighty5]

Dude... i was wondering the samething about 6 months ago and went and just did some upgrades and already regret doing them... i rebulit my carb(quadrajunk) and did a intake and some other minor things and other than about 1 mile more per gallon i got no more power... i am planning on upgrading to a 350 before summer but from what i hear its hard to do when your caprice is your daily driver any way if i was you stay away from 305's that what every one says!!!!!

[bhw33191]

Originally Posted by beat88ls

quadrajet carbs may be disrespected but i would stick with the e4me. i may be wrong (please correct me if so) but i recall reading somewhere the e4me quadrajet flows 600+cfm. my buddy always had "toys" his first car was a 72 chevelle, his old man had a 56 chev belair with a m22 4speed and a 305 from a camaro. they dumped crazy money into the engine, cam, heads, complete low end and after all the work the engine was still lacking. they eventually dumped the 305 and picked up a 327... if you are willing to tear apart your engine and be without your car long enough to get it back together why not go with a 350?

Yeah that might be true. I even know someone with a 350 they were selling for $100 so i hope they still have it. Of course it needed to be rebuilt though. I just thought a rebuild would be too much money..but hey it'd be a good engine that i could dump into almost any GM RWD car so its very flexible.

[j cAT]

Originally Posted by bhw33191

Yeah that might be true. I even know someone with a 350 they were selling for $100 so i hope they still have it. Of course it needed to be rebuilt though. I just thought a rebuild would be too much money..but hey it'd be a good engine that i could dump into almost any GM RWD car so its very flexible.

get a bad 350 motor cheap. then get the motor worked on to your specifications.. why pay more for a good 350 if your gonna do some power modifications ?

when its all fixed up pop it in..little down time ..

[Blt2Lst]

Originally Posted by beat88ls

quadrajet carbs may be disrespected but i would stick with the e4me. i may be wrong (please correct me if so)

Those Q-Jets flow around 750 CFM

[beat88ls]

Originally Posted by Blt2Lst

Those Q-Jets flow around 750 CFM

wow, a bit more than i thought

[j cAT]

Originally Posted by beat88ls

wow, a bit more than i thought

how is the 305 with a quadrajet gonna handle 750 that is too high..

its 600..

[Blt2Lst]

Originally Posted by j cAT

how is the 305 with a quadrajet gonna handle 750 that is too high..

its 600..

I realize even a mild 305 will never need the 750 CFM but that's the flow rate on the q-jet.

http://smicarburetor.com/products/sf...ID2/9/sfID3/32

[j cAT]

Originally Posted by Blt2Lst

I realize even a mild 305 will never need the 750 CFM but that's the flow rate on the q-jet.

http://smicarburetor.com/products/sf...ID2/9/sfID3/32

if you look closely you will see these are not for any stock 305cu engine.
these carb's can be modified however and maybe 900cfm can be had..

I did a search and found that these can be jetted to 1000cfm...

the 305 cu is a problem using a higher cfm...the intake ports are restricted in the design thats why you go with the 350cu..
the 350 cu is a common boat engine..this is where the high cfm carbs are used..
maybe you could put a 650 cfm and get away with it ...could destroy the cat converter ...

[wafrederick]

Plus the 350 out of Boats have a differant camshaft,a RV cam which has to be changed.Another problem with rebuilding an engine is finding someone that stands behind their work on machine work and does not screw you around.

[Blt2Lst]

Originally Posted by j cAT

if you look closely you will see these are not for any stock 305cu engine..

Their electronic stage 1 Q-jet for my stock olds 307ci is also rated at 750 CFM so they claim.

I plan on having them do a rebuild on mine soon.