What to do with my 305?

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midwestls

Royal Smart Person
Aug 15, 2007
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Bismarck North Dakota
But, if you start getting into changing cam's and heads and everything else wouldn't if have made sense to do it to a 350 and got more power for the same amount of money, and probably the same gas mileage as the 305? My 350 I have in my car right now gets like 8mpg better on the highway then my 305 did in my 86 LS I had last year, and that one was completely stock and no where near as quick. Something to think about. :shock:
 

megaladon6

Comic Book Super Hero
May 29, 2006
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Danbury, CT
actually, i'm wondering if you could bolt a q-jet to a TBI intake? if so, you could junkyard source the heads and intake, replace the TBI with a non-computer carb, and only have to buy the cam kit. that would really keep the price down.
i just ran the build through cam quest 6 and we're looking at some MAJOR low end torque. since normal driving is in the 1500-300rpm range, and the torque/efficiency peak is at 2k it'd probably do pretty damn well at MPG. and it'd be really fun to drive! not a huge amount of HP, only about 250 or so but it's enough.
 

TBRtat2

Greasemonkey
Aug 30, 2008
180
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Take your stock set of heads and give them a MILD porting (just enough to knock off the casting marks) Guys years ago would take the 305 heads and put them on 350's to raise the comp. ratio.

Add a set of headers to ur list (they will still work for a 350 or 383)
Ditch the glass packs and put a set of good open chamber mufflers (you will be glad you did when its done, cause it will sound so much better, just my opinon, and the mufflers should flow just as good, if you get some good ones) (also a lil bit of backpresure can help economy)
And a good set of headers can increase economy well increasing horse power

Go for the intake for sure (once again you can use it on the 350 or 383 later)

as far as a cam goes, i would try to find a stock style h.o. cam, or a good heavy duty RV, truck cam, you will have more off the line tourqe, then some high power cams

And you might be able to find a "all ready to go" distributer, with everything you want (and again you can use it on a 350 if you decide to swap later)

As far as the carb, get urself a modid quadrajet, which will perfor like a highend carb, but get a lot more economy (if you keep you foot out of it), and leave you with more to go if you decide to use it :twisted:

and if it has that low of miles, the stock oil pump should soot you just fine, just throw a bottle of lucas oil additive in the motor and you should be fine, even in hot weather

With all that you should be able to get over 15mpg in city, and even higher on the highway (depending on how you drive it)

I say this cause I used to 18mpg in city in a 1978 buick electra 225 (over 5000 lbs of car), with the same motor that i am putting in my cutlass, Which is a 40 over 403 with heavy duty rv cam, edelbrock intake and carb and a few other things :twisted:


Also a side note, a 305 can be a high power engine, if built right, and no it does NOT cost more to build a 305, instead of a 350, Remeber most of the parts are the same, short of crank and pistons, also a shorter stroke and smaller pistons like whats in the 305, are ideal for a high rpm motor.
 

Phoenyx

Royal Smart Person
Jun 27, 2007
2,392
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Alberta, Canada
Thanks to everyone for the input. But now I still don't know what to do lol. But like some earlier posts said, Maybe I should just get duals and give it a good tune up. And spend my money on other things like suspension.

But now I have two other questions.

One is about the module in the distributer. I've had experiences with those dieing in the past. SO when I do my tune up I want to replace mine. What do you guys recomend? Are the fancy aftermarket ones worth it, or should I just go with a stock replacement?

And second, spark plugs. Should I stick with stock replacements, or will the duels change things enough that I will need a different type?

And one last thing. I live in a place where we don't have tough emission laws. Would getting rid of the vacume hose nightmare help or hut things?
 

megaladon6

Comic Book Super Hero
May 29, 2006
4,006
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Danbury, CT
i'd stick with a stock module, but you might want to spend the money on a name brand one as opposed to some autozone POS. if you have an Autopart International/Foreign Autoparts i'd go to them. there's one near me and they carry very good quality parts and the prices are the same as the cheap crap. same with spark plugs, stick with copper. going to NGK might be worth a bit, but going to platinum won't do crap. i would use platinum and a MSD or Pertronix module when you build the 350 though.
you can get rid of most of the vac lines. i'd keep the carbon canister, PCV, and any necessary sensors.
 

TBRtat2

Greasemonkey
Aug 30, 2008
180
0
0
As far as a module goes, stock would soot you fine, but some do claim to increase response, hosepower. My self I always just went with a stock replament, unless We went full race ready,(race only style) So that I would say go with what you can afford, maybe try to find a hiperf 1 that is 50 state legal.(jegs, summit, etc.)

I would recomend a set of bosch platinums(I have the best results with them), the standard ones, not +2's or +4's or anything like that. Althoe everyone has there favs. either way Just go with a "stock" Replacment, the guy at the parts store will tell which ones will work for that car and engine.

Which makes me think of something else, I would recomend a hotter ignition coil, they make direct hiperf replacments for eveything nowadays, And it will increase power and economy.(a hotter coil will burn the fuel more compleatly=more power, less wasted fuel)

As for the emisions, removing everything, will increase power, but can decrease your emisions, also when doing duals you "Tecnichly" need to have 2 converters if your running true dual front to back.
But there is something you can due to help pass the c.o. test, just detune your motor for the test, cut the fuel way down and turn down your timeing, the motor should run fine, but it wont have any power
(caused buy the lack of fuel and timing, which means less raw fuel coming out, which means a better result in the test)

Also if you want to get the best results from duals, get the headers, they do make they 50 state legal headers.

Althoe with duals if they only stick the test tool in 1 pipe, they only read the output of half the motor, which helps to lower the emision reading


Now if you want to get around the emission laws altogether, just buy an older car, one without a converter, as I understand any car that didnt come stock with a converter, is exempt from the emision laws.(check local laws)
 

Phoenyx

Royal Smart Person
Jun 27, 2007
2,392
7
0
Alberta, Canada
Well where I live we don't have to worry about the emissions laws :) so that's not a worry.
 

pose_442

Greasemonkey
Feb 12, 2007
243
2
18
IMHO, find a good 87-90 350 Truck EFI engine, go with either the TBI or carb, swap it out and roll.

IIRC, these had the roller cams which are more efficient since there is less rolling friction. These engines are easy to find and do very well in stock form.

If you keep the TBI, you can get a JET or Hyperech chip for the ECM that will improve power and MPG's even more.
 
Sep 1, 2006
6,687
33
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Tampa Bay Area
A Quadrajet will not fit a TBI intake manifold. It has a 2 barrel design and a odd bolt pattern.
 

megaladon6

Comic Book Super Hero
May 29, 2006
4,006
15
0
Danbury, CT
ohhhh well
 
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