Everything I need to know about tuning a 305

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oldmansmonte

G-Body Guru
Oct 29, 2010
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Buffalo, NY
DmcL said:
Nah it's not about beating things.. If I want to do that I'd bring out my 06 wrx which is roughly 270bhp/320lbft which I can patch launch control and flat foot shift on in about 5 mins with my laptop lol it runs high 13's on stock turbo and stock cats. Only have a handful of mods and remapping by me.

I want ideally about 300bhp from the 305. You guys are likely thinking in whp. Probably about 250whp I'd like to see from it. Basically enough for it to move decently and spin wheels/do some donuts once I fit a posi or something. Eventually I might want to make some decent power but for now anyway I just want to make the 305 a bit more fun.

I got a pic of what I think must be the part number of the intake manifold. Anyone know of this manifold and would I need to look at something aftermarket for the sort of hp I'm after?


If you have a WRX why are you bothering trying to get horsies from a 305? What kind of car is this anyways?
 

autonaut

Greasemonkey
Feb 22, 2014
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Your decision. Just so you know aproximately what gains to expect:

My 87 el camino did 241 crank hp by adding the previously mentioned mods. This was on a dyno. Stock figure was 150 i believe so i did pick up 90hp and equal torque. It hauled nice, and sounded real good. But compared to my new 350 it was a turd.
 

oldmansmonte

G-Body Guru
Oct 29, 2010
594
348
63
Buffalo, NY
autonaut said:
Your decision. Just so you know aproximately what gains to expect:

My 87 el camino did 241 crank hp by adding the previously mentioned mods. This was on a dyno. Stock figure was 150 i believe so i did pick up 90hp and equal torque. It hauled nice, and sounded real good. But compared to my new 350 it was a turd.


Nice. Curious, what gears are in that thing?
 

autonaut

Greasemonkey
Feb 22, 2014
209
31
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oldmansmonte said:
autonaut said:
Your decision. Just so you know aproximately what gains to expect:

My 87 el camino did 241 crank hp by adding the previously mentioned mods. This was on a dyno. Stock figure was 150 i believe so i did pick up 90hp and equal torque. It hauled nice, and sounded real good. But compared to my new 350 it was a turd.


Nice. Curious, what gears are in that thing?
I sold it to build a new one. This is the new one. They both have 2.41 rears. Although this one is getting a 442 olds 8.5 3.42 rear end once i get the time to rebuild it. So far it only needs new body bushings. New bushings for all control arms. new shocks, springs, f41 rear sway bare, swap the stock front bar for a 36mm hollow one, and then some bracing various places.. I just need the time. Im working alot these days.
IMG_8007.jpg
 

81msw79

Master Mechanic
May 5, 2013
391
126
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roselle park , nj
I read the o.p.'s intro post. Here is a link for everyone who is asking where he is from and about the car
viewtopic.php?f=24&t=53506&start=0#.VDcI1BnD_qA

I understand his thoughts of maybe not finding a sbc real easy. I would suggest calling the ase mechanic that i found the car through to see if he may be able to help track down a decent 350 or one worth rebiulding. He may even be able to set you up with a good machine shop to help biuld it. Jegs and summit racing will ship international or buy the parts when you are state side and ship them home before you leave.
I have done everything you have done and cammed a stock 305. It is not really worth the time and funds. Save up and do the 350. You will be alot happier. And you mentioned in your other thread about brakes. If you do the 2wd front blazer brakes you can get adapter brackets to run corvette brakes.
 

DmcL

Not-quite-so-new-guy
Sep 30, 2014
33
0
6
Basically I just want enough for the car to be able do do easy burnouts and all that fun stuff.. The wrx is great but I miss good old fashioned rwd. I have an 89 bmw 325i which was never driving straight lol the Bmw will probably be sold so I'd like enough power to have some fun with the Monte.

Plan is to work with the 305 and then if I want more look into other options.
 

DRIVEN

Geezer
Apr 25, 2009
8,087
14,570
113
*CENSORED*
DmcL said:
I got a pic of what I think must be the part number of the intake manifold. Anyone know of this manifold and would I need to look at something aftermarket for the sort of hp I'm after?
I can't tell if the last digit is a 3 or 5. Either way, it's early-mid '80s 305. Nothing special.
 

MUELLERBU

Not-quite-so-new-guy
Apr 6, 2013
47
0
6
Delta, Bc
305 vortec heads ported & polished, machined valve guides for higher lift, new springs, bigger cam, vortec manifold, headers, true dual exhaust & you'll get the best out of yor 305 but unless your a craigslist shark your 350 is almost paid for'
PS those 305 vortec flow numbers are pretty impressive with small valves & I don't care what the internet says
 

DmcL

Not-quite-so-new-guy
Sep 30, 2014
33
0
6
The guy I bought the Monte off swears the 305 is a majorly overlooked engine. He's an ase certified master who lives here in Ireland (hence doc's don't grow on trees here) and he's built plenty of drag engines for people with US imports here. The Monte was one of his cars. He was definitely smart putting in a lower than stock converter on the Monte, it suits the 305 perfectly the way it sits.

Regarding ratchet shifters.. Would I need a reverse valve body for a shifter that you pull to change up rather than push?
 

autonaut

Greasemonkey
Feb 22, 2014
209
31
18
It's overlooked for efficiency. It can do great mileage and have good torque. But for your purpose is it not suited.
Think about. Why does almost everone on the internet tell people to swap them for a 350 or bigger?
I am. I have had several 305's with "full bolt ons". I have also had all aluminum bigblocs chevys, regular bigblocks, pontiac olds and one buick, LS engines and several of the infamous traditional 350's.

If you want to throw 3k in parts to have a mediocre 305 that will get its *ss handed to it by Vtec Hondas at the stoplight, GO AHEAD. But dont say you wasnt informed of the outcome.
 
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