305 blocks- whats the best one to use ?
 

I now have a cracked 305 block. Is there any other 305 blocks that are good, for a stocker ?(I have heard that 307's sleeved down are the best to use.) I have seen a few 305 (5.0) generator motors and figured that would have to be stronger block. Anyone have a connection to Generac or Kohler ? This one cracked at the top of #5 hole.
If you have any ideas, please pass them along. I want to get going again soon !

Thanks
Kenny
kwigracing@yahoo.com

Re: 305 blocks- whats the best one to use ?
 

Kenny, I use an early 305 block (2-piece rear seal) in my stocker. I have the block filled
with Hard-Blok and have never had any problems with cracks. I am curious as to why the
block would crack up there at the top. Did your block have any core shift? I have heard
GM has a "Bow-Tie" 305 block but, I have never seen one. If this is the first incident with
cracking I'd say you just got a bad core. That's my two cents worth.

Reggie Winkles
4102 J/Stick

Re: 305 blocks- whats the best one to use ?
 

Kenny--GM did offer 2 blocks for the 305CI------A stock version of the block part#-10066098 & a Bowtie block part# -10051181(casting # 10051182)--The Bowtie block is machined for a 1 piece rear main seal and if you need a 2 piece seal you will need cshaft seal adapter #10051118 -- I do not know if these numbers have been changed or are up to date or if either of these blocks are still available from GM..Also remember that a stock production SBC block weighs approx. 152 pounds and a Bowtie SBC block will weigh approx 183 pounds . Good luck---Comp 387

Re: 305 blocks- whats the best one to use ?
 

Thanks Reggie, and Dick. I'll check into that block. Mine has hardblock in it.

Re: 305 blocks- whats the best one to use ?
 

steve is right...take a 350 4 bolt block & sleeve it down to 305....my machinest dose it..about $620.oo though.

Re: 305 blocks- whats the best one to use ?
 

Kenny,

Better not use a 4-bolt 350 block as a core to sleeve, as they aren't a legal replacement for a 305 (based on a call to NHRA). The 305's were all 2-bolt and that's what NHRA wants to see IF the pan ever comes off. The best block to use if you can find one is the '68, '69 307 block. Many were cored as 350's so you end up with the very thick walls of a 350 but can use a more generally available sleeve.

Jerry

Re: 305 blocks- whats the best one to use ?
 

Kenny,
Jerry is giving you the correct info, they will not accept the 4 bolt block, I learned the hard way. Some run them but they are not legal.

Re: 305 blocks- whats the best one to use ?
 

The 80 corvette had a 305 4 bolt block

Re: 305 blocks- whats the best one to use ?
 

Thanks guys. I do appreciate the info.

Just for the sake of asking, how much extra would a block weigh , with all sleeved ? Is it lighter than that Bowtie block, Dick and Reggie mentioned ?

Re: 305 blocks- whats the best one to use ?
 

Don,

Re: 305 blocks- whats the best one to use ?
 

I think the "201"? truck blocks are the stock 305 blocks of choice. Seems I remember the Shermans using them when they ran that combo a few years ago. Cliff said they were stronger.

Re: 305 blocks- whats the best one to use ?
 

Kenny,

The best block to use is the block that you have. This would be most cost effective considering the total cost to machine another block to duplicate what you already have. Sleeve that block. Knowing the history of the engine and the head issue-this crack was caused by water in the cylinder. Just my two cents.

Respectfully submitted,

Steve Williams

Re: 305 blocks- whats the best one to use ?
 

Kenny,Don & all
I finnaly got back on line. About 6 yrs ago I did the sleeved 350 4 bolt deal. When we began to assemble we were told what Jerry told you. I called Calif. and they said no way. I guess we need to ask Travis about that 80 vett. They should be ok if that is correct. I think I got 2 cases of beer for my $800.00 block.
Jim

Re: 305 blocks- whats the best one to use ?
 

Mortec shows 2 different castings # for 305 4bolt blocks. They say there for hd trucks of course there Canadian.

John

Re: 305 blocks- whats the best one to use ?
 

Thats really suprising , I live in Canada and have never heard of a production 4 bolt main 305 block .
I am going to investigate this a little further, just for my own interest. I remember a few folks claiming their mid '80s Monte Carlo SS were 4 bolt but when they tore them down they were always 2 bolt main.

I guess you have to wonder why a HD truck would be 305 equipped in the first place ?

Re: 305 blocks- whats the best one to use ?
 

Casting # 361979 460778


John

Re: 305 blocks- whats the best one to use ?
 

http://www.mortec.com/castnum.htm

Re: 305 blocks- whats the best one to use ?
 

Really dont think they exist ... has anyone ever seen one ??? Small block interchange manual SA Design #SA 55 shows #361979 as 305 78-79 2 bolt main and #460778 as the same . (pg7). It states "these5.0 liter Gen. 1 motors are all medium journal 2.45" blocks and production blocks were only made with two-bolt main bearing caps". (pg 13 ).

Re: 305 blocks- whats the best one to use ?
 

Yes i use to have one, they were mainly used for marine use.

Re: 305 blocks- whats the best one to use ?
 

I checked my core supply i have a 305 block #460778 and it is a 4 bolt main. I also have 350 010 blocks that are 4 bolt and 2 bolt.

Re: 305 blocks- whats the best one to use ?
 

I stand corrected gentleman. I never had heard of or seen a 4 bolt 305. Thanks for the positive proof.