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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 09jjtierney on December 16, 2014, 06:44:24 AM

Title: 305??
Post by: 09jjtierney on December 16, 2014, 06:44:24 AM
I have a 305 crate motor with less than 20k. Wanting to do some upgrades to get more power, but could a 305 really be wort it or should I just swap for something bigger?
Title: Re: 305??
Post by: Captkaos on December 16, 2014, 03:26:48 PM
What are you wanting to achieve, how much power?  What is the usage?

Chris Lucas
73-87chevytrucks.com
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Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 07:26:08 PM
Its a daily driver for now and one day hope to be a show quality truck.I'm not looking for enough power to race or anything just want to improve enough to get on the the highway and keep up with the other cars. Right now a Prius could get up to speed quicker and pass me if I had a head start haha. And that doesn't settle well.. I know my way around a motor and how everything works but as far as blueprinting an improvement plan I don't know where to start.
Title: Re: 305??
Post by: VileZambonie on December 16, 2014, 07:28:41 PM
Sounds like you need to start at the back end. What is your final drive ratio? What trans do you have?
Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 07:43:46 PM
I have 700r4 and I don't know what final drive is
Title: Re: 305??
Post by: VileZambonie on December 16, 2014, 07:47:04 PM
Well that's where you should start. Tell us more about your truck
Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 07:59:23 PM
Ill tell you anything you want to know. To be honest I don't know how to find out what the final drive ratio is. I know I just had the 700r4 rebuilt <2000 miles ago. Motor is stock crate motor from advance auto I believe.  4 barrel Edelbrock that I can't ever seem to get adjusted quite right. Rear end is stock from what I can tell.
Title: Re: 305??
Post by: VileZambonie on December 16, 2014, 08:04:27 PM
Year, make, model?
Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 08:09:34 PM
1985 Chevy c20 custom deluxe. And I don't know that it makes a difference on specs but originally it was a fire truck
Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 08:11:05 PM
Fleetside standard cab long bed 2wd
Title: Re: 305??
Post by: VileZambonie on December 16, 2014, 08:12:59 PM
check the glove box to see if the spid label is there. If so see if it lists the rear axle ratio or code
Title: Re: 305??
Post by: gwcrim on December 16, 2014, 08:42:09 PM
A 305 is a small motor with small valves.  Other than a 4 barrel and headers, you'd be better off spending money on a good 350 (or more.)

I changed my rear gears from 2.7 to 3.73 and it didn't accelerate any  better at all.  A 305 isn't a performance engine.
Title: Re: 305??
Post by: 09jjtierney on December 16, 2014, 09:31:27 PM
Sticker say 3.23 and option code is gu5
Title: Re: 305??
Post by: flips87c30 on December 17, 2014, 08:05:11 AM
My 92 Chevy has a 305 with a 700r4 and I love it granted it is TBI but it has plenty of power.
Title: Re: 305??
Post by: VileZambonie on December 17, 2014, 07:18:28 PM
What size tires are you running?

I changed my rear gears from 2.7 to 3.73 and it didn't accelerate any  better at all.  A 305 isn't a performance engine.

Are you sure you didn't put the 2.73 back in?  :P

Title: Re: 305??
Post by: gwcrim on December 18, 2014, 09:09:03 AM
Tires are 26".  I did 0-60 time with a GPS.   It went from 11.5 to 11.2.  So there was a minor improvement.  A 1980 305 two barrel is not a performance engine by any stretch of the imagination.
Title: Re: 305??
Post by: 80midnightchevy on December 20, 2014, 01:16:41 AM
I have the same set up, except I have a t350 tranny. The 305 and 350 are very similar in specs. GM said the 305 was the economical V8, while the 350 is the power. The 305 saved people money on gas in the 70/80 gas shortage while still giving people the opportunity to say I have a v8. You have a 5300 lbs truck and the 305 won't get it up to speed very well. You're better off finding a junkyard and rebuilding a 350/383/454, money situation dictating. If money is not an issue, buy a new fuel injected LS motor.