PONTIAC Best 305 Rebuild Kits?

g0thiac

Apprentice
Sep 6, 2020
80
8
I'm trying to see about options for rebuilding a 305 in my 1984 Pontiac Bonneville.

It's a Chev small block, so nothing fancy.

However, the only reason why I am considering a rebuild, and not throwing in a 350, is to keep things numbers matching.

Any ideas? Cheers!

-Chris
 

08Malibu

G-Body Guru
Feb 9, 2014
555
93
North Jersey
I'm trying to see about options for rebuilding a 305 in my 1984 Pontiac Bonneville.

It's a Chev small block, so nothing fancy.

However, the only reason why I am considering a rebuild, and not throwing in a 350, is to keep things numbers matching.

Any ideas? Cheers!

-Chris
There’s no reason to keep a car with a 305 numbers matching.
 

pontiac guy

Master Mechanic
Oct 28, 2016
465
93
Royse City, TX
Don't mind the nay sayers too much. They are correct that numbers matching isn't (at this time and likely ever) important on a run of the mill G body, however....
There is nothing inherently wrong with a 305. They are durable, parts are plentiful and they can be better on fuel than the 350. You can even make decent power out of them. Yes a 350 will always make more power. It's also true that a 383 will out power a 350 and a 400 SBC will make more yet. If you are doing a stock rebuild then you can source all your parts from Rock Auto or your favorite online source of choice. Dont bother with hypereutectic pistons or forged. Stick with name brands though. Just get your rods reconditioned have the bores cleaned up and get your crank redone. A good valve job and you're golden.

If you want a little more out of it but don't want to break the bank. Go for Vortec heads and the matching intake. Use caution there because your quadrajets is a spreadbore and most vortec intakes are square bore. Get the right intake or use an adapter. One thing I would do for sure is a quality timing chain and a cam button. Its the Achilles heel of the SBC. Inaccurate cam timing because the stupid thing isn't retained. Feel free to PM me if you'd like. I have a 305 I'm in the middle of right now. I'll be glad to share any info you may need.
 

Cuse99

Apprentice
Dec 21, 2020
99
18
I'm trying to see about options for rebuilding a 305 in my 1984 Pontiac Bonneville.

It's a Chev small block, so nothing fancy.

However, the only reason why I am considering a rebuild, and not throwing in a 350, is to keep things numbers matching.

Any ideas? Cheers!

-Chris
we were just talking about this in another thread. I've been doing some research and hitting 300 hp in a 305 is ver doable. Doesn't seam to be too many drivers on this forum but there drivers out here. Here is an article, 1 of many, I found by doing a yahoo search.


I'm looking into this myself. Good luck.
 
  • Like
Reactions: g0thiac

Cuse99

Apprentice
Dec 21, 2020
99
18
Ok I have 1 more comment. Go to youtube and search 305 build. See what you get. I don't think you'll be disappointed.
 
Last edited:
  • Like
Reactions: g0thiac

g0thiac

Apprentice
Thread starter
Sep 6, 2020
80
8
There’s no reason to keep a car with a 305 numbers matching.
And theres no reason why you had to post that comment. I'm not a fan of LS Swaps, but you don't hear me posting negative comments there, just saying.

Hmm.png
 
  • Like
Reactions: James Morris

g0thiac

Apprentice
Thread starter
Sep 6, 2020
80
8
Don't mind the nay sayers too much. They are correct that numbers matching isn't (at this time and likely ever) important on a run of the mill G body, however....
There is nothing inherently wrong with a 305. They are durable, parts are plentiful and they can be better on fuel than the 350. You can even make decent power out of them. Yes a 350 will always make more power. It's also true that a 383 will out power a 350 and a 400 SBC will make more yet. If you are doing a stock rebuild then you can source all your parts from Rock Auto or your favorite online source of choice. Dont bother with hypereutectic pistons or forged. Stick with name brands though. Just get your rods reconditioned have the bores cleaned up and get your crank redone. A good valve job and you're golden.

If you want a little more out of it but don't want to break the bank. Go for Vortec heads and the matching intake. Use caution there because your quadrajets is a spreadbore and most vortec intakes are square bore. Get the right intake or use an adapter. One thing I would do for sure is a quality timing chain and a cam button. Its the Achilles heel of the SBC. Inaccurate cam timing because the stupid thing isn't retained. Feel free to PM me if you'd like. I have a 305 I'm in the middle of right now. I'll be glad to share any info you may need.
I'll try not to, I just don't appreciate people judging my preferences, when this topic isn't about showing off or swapping motors, but rather rebuilding them.

Now a 383 in my Chevrolet Caprice, I would love to do that.

And thanks, I will definitely give you a shout when it's time.
 

g0thiac

Apprentice
Thread starter
Sep 6, 2020
80
8
we were just talking about this in another thread. I've been doing some research and hitting 300 hp in a 305 is ver doable. Doesn't seam to be too many drivers on this forum but there drivers out here. Here is an article, 1 of many, I found by doing a yahoo search.


I'm looking into this myself. Good luck.
Thanks for the links man! I'll take a look at it :)
 

g0thiac

Apprentice
Thread starter
Sep 6, 2020
80
8
Ok I have 1 more comment. Go to youtube and teach 305 build. See what you get. I don't think you'll be disappointed.
Will do, thanks for the reply :)
 

ck80

Royal Smart Person
Feb 18, 2014
1,695
113
I'll try not to, I just don't appreciate people judging my preferences, when this topic isn't about showing off or swapping motors, but rather rebuilding them.

Now a 383 in my Chevrolet Caprice, I would love to do that.

And thanks, I will definitely give you a shout when it's time.
Right now there are some very good reasons people haven't mentioned for you to think about another direction... and it's all about the long term.

Rebuilding a motor isnt cheap... at least not done right. You're probably looking at an easy $500-1000 or more on the low end by the time you've torn down, hot tanked, honed/bored, bought new parts etc.

Considerations

1) going to roller cam setup - flat tappet cams require lots of extra diligence as they keep reformumating oils, which they did yet again recently. With a roller you don't need to worry about the lack of metals (zinc etc) in modern oils and pricey additives.

2) building an e85 friendly motor. Let's face it, war has been declared on the ICE. Maybe you don't have longterm plans on the car. But if you do, its time to invest wisely for the future. My bet is you see ethanol content raised again with the idea being EV or e85 hybrids. In a carb motor, e85 is about 25-30% less energy than regular gas and needs to be planned for accordingly- both fuel volume and all you various rubber/plastic parts and seals from tank forward.

3) if the idea is to have the correct motor... but you swap out the original heads, carb, ignition system, etc... it does t really count as numbers matching motor, just original block. Beyond displacement, tere are benefits to the 1pc rear main seal, to getting a motor with roller cam already in place, serpentine setup, all down to even running a slightly reworked l31 motor without rebuilding it or some such similar option.

The idea isn't necessarily kill the 305s... it's more a case where people new to the hobby and type of cars may not see the long game, and the cost vs benefit. Replacing a 305 doesn't have to mean an ls swap. Theres many other acceptable options to think about.

If you are set on doing it, you'll wind up with better quality parts overall if you pick components individually. The "kits" are basically just the cheapest Chinese junk thrown in a box and marked up in price for the uninitiated when you're ordering for a smog era 305.
 
G-Body Performance Upgrades

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

contact[email protected]for info on becoming a sponsor