Everything I need to know about tuning a 305

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DmcL

Not-quite-so-new-guy
Sep 30, 2014
33
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6
Definitely not putting 3k into it. Thinking a cam and possibly a different intake manifold plus what's already on it will work well.

Beyond that either boost, nitrous or another engine. As is the car does about 22mpg. Doesn't seem much worse than my wrx on fuel.

Anyone know a good ballpark air/fuel ratio for best power on these carbed engines? Previous owner has it tuned pretty well but he tuned via plugs and checking emissions. I have a wideband so I can dial it in a bit better.
 

autonaut

Greasemonkey
Feb 22, 2014
209
31
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Different cam and different intake manifold will not get you anywhere near 300 hp on a 305.. Those heads are only good for 4500 rpm. How will you manage to extract 300 hp below 4500 rpm? No cam will change this!

I give up.

Why am i even trying to guide you. You dont know anything about tuning and clearly you dont want to learn either.
 

pencero

Royal Smart Person
Feb 20, 2008
1,466
25
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Ind.
305's are just a 'hood fad'. People get 1 of those cheap turbos off ebay slap it on a stock 305, maybe do some cams maybe not even, and beat it to death pushing as much boost as they can. You won't get past like 325 hp on your best day is what everyone is trying to say its kind of a waste of money unless you happen into all the parts super cheap like you already work at a parts yard or something.. otherwise its just a huge waste of money
 

DRIVEN

Geezer
Apr 25, 2009
8,087
14,570
113
*CENSORED*
Could always stroke it to 334. An honest 300hp should be doable with the extra cubes.
 

don4life

Apprentice
Jun 22, 2014
76
2
8
if you just want quicker launches and burnouts then just put lower gears in the rearend and forget about blowing money on the 305
 

DmcL

Not-quite-so-new-guy
Sep 30, 2014
33
0
6
Dunno about rear end gearing.. The tach is way high and I don't know how high it revs at 60 or 70mph. I want to keep half decent fuel consumption also because fuel prices here are nuts compared to what u got a pay. We pay about £1.30 a liter. Considering £1.30 is maybe like $2.10 and there's how many liters in a gallon? You get the idea lol

I'd be plenty happy with around 300hp honestly. Even maybe 270 ish as that's about where my wrx is and it moves nicely.
 

DmcL

Not-quite-so-new-guy
Sep 30, 2014
33
0
6
Just thinking.. Giggle gas might be the ticket. I could build the 305 a little with an intake and cam, maybe pick up a spare pair of HO heads and get them worked and fit larger valves (replace the smaller of the stock ones) which I think I read was the exhaust valves which should give a little better flow but not run into clearance issues.

I'd get a nice honest boost in power from that stuff and could install a 100-150 wet kit for when I want it to really move.

I think that might be my best bet all things considered. I'd retain decent fuel economy but also have a bit of power on tap and I wouldn't need to trawl eBay for sketchy 350 blocks etc.

There is one place that sells 350 crate engines here but it would cost about £3k whereas I could do those things to the 305 for like 1/3 the price and have better fuel consumption.

Long term I may look at building a 350 or something for it but that would be way down the line if ever. Also I'm led to believe most stuff I get for the 305 could be used on a 350.
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,875
2,630
113
Galaxy far far away
There is a lot of ignorance about 305s on the Internet, people blindly bad mouthing them and parroting what they read. It is not hard to get 300 hp, out of a 305, 059 vortec heads and a decent cam will get 300 easy. Heck I am making 240 HP, with stock heads with a 2040 cam and TES, headers. However 300 is about the limit for 305s, if you want more than that then go 350 or bigger. Montecarloss.com has a nice writeup for beefing up a 305 on their home page and thridgen.org is the most knowledgeable about 305 performance, this place only knows 350 performance or ls swapping. The mistake people make is supping up a 305 like a 350, 305s require different techniques than 350s. Indeed 305s are very underrated motors.
 

88ss408

Master Mechanic
Feb 25, 2007
281
34
28
baie st anne n.b
I am assuming that a full rebuild is out of the question ?
So here is what I recommend. Not sure how hard parts are to find where you are but a set of 113 heads would put you ahead of the game. But if not the 416 heads you have will do. But will need a lot of work.
1.94/1.5 valves gasket match the ports and some bowl blend.
For caniI would use a XE 262 or XE 268. Long tube headers and duals.
And air gap intake 650 carb and recurved HEI
 

84cutspreme

Royal Smart Person
Jun 4, 2009
1,147
153
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