what to do with this 305?

Probably a long shot, but if this is a late 70's (77-79) engine there were problems with a cold start knock that was traced to excessive clearance in the front main bearing. It was addressed in a TSB at the time. The fix was selective fit front bearing shells.

Also, that era had camshafts with soft lobes, we replaced a bunch of them under warranty back then.

If the engine was originally painted corporate blue be aware of these issues also. I remember this from back then as the 305 in my 77 El Camino had that, along with excessive oil consumption until at 37k I lost a lobe on my camshaft in '79. And it was getting regular oil changes at the dealership that I worked at then along with GM Engine Oil Supplement added at each oil change.

 

shit, this motor is out of a '79 truck...so I guess a cam change is a for sure thing now lol

 

Ok,why is that? I have actual experience that might say otherwise........

 

305 crank and rods are the same as a 350 - pull the internals and buy a 350 block

Heads, if they are 1.94's see what it takes to freshen them up, or just lap the valves in and run umbrella seals - they dont flow much over 5000 rpm, depends on how much cam you want to run if they will work for you.

Keep all your brackets, balancer, etc to dress your new engine.

If you do freshen the 305 dont spend much, hone it, ring and bearings. if a 305 block needs bored throw it away.

 

Indy, you are kind of right on the crank. The stroke and bearing sizes are the same, but the balance factor is slightly different. Again going back to the bad old days, when I was in management in that era, one of our inexperienced counterman at the dealership gave the wrong crank out, put a 350 crank in a 305. We found out when the warranty claim was bounced due to a incorrect part number on the order. A quick meeting with the service manager, a trip to the parts book, and the fact that the engine was in a Caprice (unlikely to be thrashed) we let it go as the car was running and on the road. Just changed the part number on the claim. The parts man never loked at the VIN code on the order, just guessed it was a 350.

punkabilly,

Probably by now if that motor has any time on it, the cam should have failed by now. Not all of them did, same situation with the cold engine knock on startup. Just wanted to let you know, as that was a LONG time ago and many people probably do not know about it. I lived it more than one way as I too got burned by a bad engine.

 

that's a pretty dumbass statement.
i think i made pretty good use of my free 305;

sure she smokes on first start up, but she's only got 90k grampa caprice miles on her, plenty of o.p., runs cool, and nobody thinks twice when i tell them "it's a 327 w/ a 3/4 race cam"



if your gonna take the time to throw a new cam & heads (or at least fix the heads on it) at the motor you should really consider spending the time & money on some new lower end bearings. i've seen breaking in a new cam on old ass lower end bearings turn into a rod-knock in no time. and a valve spring upgrade wouldnt hurt either,

again, it all comes down to time/money/return on investment of both.

 

Rudebaker is right!

Summit's version of the old Performer cam....

But if it was me, I would step over a 305 as I packed off a free 307 engine right out the door.

Now that said, I've posted many times over on both T/C's and NastyZ28 mag links to several 305 engine build-ups that have been done over the years, one of which is slightly above 400hp.

So if you want to, please look them up under my handle.

Us old guy's know that we can take a 307, de-stroke it down to the 283, 3" stroke, and then hotrod the hell out of it and GO big engine hunting!!

He, He!!

Or make a 4"x4" = 400" engine out of it the hard way like of old!!

Like the lovely Miss Dolly say's, "It's like 5 pound a sugar in a three pound bag", and I love Miss Dolly.

pdq67

 

got one in my coupe, and i love it. it burns a little oil. its from an 88 camaro with vortec heads and roller cam. it run real strong[ i've embarressed a few people with it!] and it gets about 27 mpg.if you put one in a light car you will be impressed. oh yea, its stone stock.

 

I don't know why and I'm sure they all didn't but I've read numerous times, been told that by GM mechanics and I owned '77, '78 and '79 305's and in stock form they liked to detonate even on mid-grade. Maybe it was the pathetic camshafts and heads they used on them back then along with the crap gas and 2 something gears but in my actual experience they seemed very prone to "rattle"........ My new '81 305 didn't but it had a 4 speed with 3.42 gears and I slipped a mild Engle cam in it.

If your experience says otherwise lay it on us, no fair holding back.

 

well now I'm reconsidering this motor

 

small block Chevy is a small block Chevy. They all run good with the right mods. It aint no hemi, nail head or Rocket. just fix what it needs for cheap and run it. you wont be sorry.

 

thanks everyone for the help, I'm going to go the cheapest route that will give me a strong reliable motor. Fix the valve seals, replace the cam with the summitt cam, new pushrods and lifters and new gaskets all the way around.

Does anyone think I should replace the lower end bearings and wrist pins?

 

yeah i already said you should replace the lower end bearings if you plan on breaking in a new cam on them. you could easily wind up with a rod knock a month down the road.

 

oh sorry, wealth of information I evidently forgot you already said that...thanks though

 

Those early 305's came with steel shim head gaskets (.010"-.015" thick) from the factory. That and cheap gas will make it knock.

 

well, you asked. dick.

 

thanks lol

 

Do us a great service and chain a dozen copper wire thieves to it and let them feel the "tow" down to the bottom of 50 or 60 feet of water. That's performance!

 

Rudebaker on 305 detonation

I thought the discussion was modified 305's...I'll take your word on stock ones.
Anyways,the small bore,small combustion chamber of the 416 or 601 head allows quite a bit of compression on pump gas.Like 9.5 actual compression,a mild cam,15 degrees initial spark advance with about 34 total give very snappy throttle response and good fuel mileage on 89 octane fuel. But if ya got to buy a lot of new parts and do machine work then a 350 is a better deal.

 

ok this thread doesn't need to turn into a "I hate 305's...they are junk...don't mess with one..etc..." Let's leave this thread for the technical aspect and make it a good useful thread.

 

i didnt know your name was dick

 

I would pull the valve covers and turn it over watching the valves if they all go up and down properly . I would simply put unbrella valve seals on it. Very easy to do without pulling the heads.

 

heads are currently off of the block because I wanted them to go to the machine shop anyways (pressure test, surface grind, valves, etc..) I talked to my buddy today about what I want to do and I think we came up with a pretty good plan that should "freshen" the motor up pretty good without breaking the bank

 

ive got a 305 tbi with a 5spd from a 96 chevy pu..in my 31 chevy sedan..
the motor runs like a champ...plenty of power...i run the factory harness and
black box..so it still uses the 2bbl tpi..
killer combo..just wish i could find valve covers for it..these ones bite...
cheapst.

 

for some reason I can't find crank bearings from summit, anyone know what to search for ?

 

http://www.summitracing.com/search/.../C10-PICKUP/Engine-Size/5-0L-305/?Ns=Rank|Asc
whew...

 

really I do appreciate your advice and efforts but if you are going to be a smart ass fuck face then please quit posting.

 

hey mang just tryn to help a brother out

 

yes, and I do appreciate that...this thread has turned into a wealth of information that is definitely going to help me when I start in with this motor.

 

So what's are your thoughts on the late '80s 305s. I've got one sitting in a van right now just needs to be yanked and put into somethin for fun.