Are LG4's 2 or 4 bolt main? I have an 86 Iroc with an LG4 and i was told not to do anything to it if it was a two bolt.

 

2.

Reports are some truck/van 305's were 4-bolt main.

The reason not to do anything to the LG4 shortblock has nothing to do with 2- or 4-bolt mains.

You can do a lot without touching the shortblock. Check out the 305 thread on the FAQ forum.

 

305...78-79...2 or 4, some Canadian assembled heavy duty truck blocks have 4-bolt. main caps ...

http://64.233.167.104/search?q=cache...nk&cd=30&gl=us

http://www.hotrodsforsale.com/hrfs/t...lock_chevy.htm


no light duty 305 were 4 bolt

light duty = 1 ton and under trucks, and all cars

no vans or pickups will have this in it, no matter where it was built or sold



and all LG4 are 2 bolt

LG4 was not a heavy duty engine lol

 

A stock LG4 block is 2 bolt main caps.

That is FALSE. My 1983 G20 fullsize van with the canadian cast LE9 305 was 4-bolt main from GM. I still have the block to prove it.

Mortec has my block listed as a 2-bolt main and refuses to change that listing, despite the multiple examples I have found and are out there.

14010203...305...80-85...2

I have two of these blocks, the stock one from my 1983 G20 with the UCK suffix code and one from a 1981 G20 van with the UAW suffix code, both are 4-bolt mains

I brought this to Ed at Mortec's attention and recieved this in reply. I replied with pictures of said blocks and nothing was changed. A subsequent email basically told me to **** off. They already changed the description of the 14022601 casting heads for myself and other members of the Chevytalk.com forum. Several of us had CC'd them and had another member get his engine black flagged on a 305 sprint because of their 53cc chambers. Mortec had them listed as 58cc chambers and the other member was called out as a "cheater" because he supposidly milled the heads (they are stock at 53cc mind you).

 

hmm interesting

i know some exist probably but i just wont totally believe it until i saw it myself

no offense

especially with the 203 casting :P

 

I have a picture of the casting number and I think one of the main caps hanging around. I know I can get a shot at the spare block that I have in the garage. They are more common in the 203 castings than some would leave to believe. They are pretty common amoung the Canadian cast 305s used in the 1981-1986 fullsize vans with the 180 HP LE9 305 and the factory 6,000 lbs tow package (stock oil/transmission cooler/etc.)

1989 model G20 Van with the factory tow package and a TH400. It is a 9.5" GM corporate 14 bolt that has 5 lug axle hubs like the chevrolet 454 SS trucks though. It was ordered with the factory tow package, G80 rear with the HE3 RPO for gears. I have verified the gear ratio is in the 3.07-3.08 range due to a cruise rpm of 1,500 rpm at 60 mph with 28.6" tall tires (P295/50/R17s).

 

so i guess that my 86 iroc has a 2 bolt main.... will how much torque/hp will a two bolt hold?

 

More than the rods.

If you make enough power/torque to break a 2-bolt 305, you're making something nearly impossible to drive on the street.

If you're thinking S/C, then you need better rods right off the top. Then you can get aftermarket splayed 4-bolt main caps (same thing as a 350).

4-bolt mains from the factory were to keep the caps from walking. It had nothing to do with strength (especially since the way the factory did it weakened the block web).

 

id like ot add/point out just for an example that the '73-80 400 sb were all 2 bolt and they seem to hold up, and actually they are more desirable than the 70-72 ones
probably because the extra bolts meant extra holes which meant less metal/material

i agree with the above about it not having to do with strength so much

good luck

 

ok thanks. I just needed to prove to someone that I could still give an LG4 some ***** without thrashing it.

 

You said the factory used 4 bolt mains to prevent cap walk. I've heard this many times, what exactly is cap walk?

 

Movement of the block and cap relative to each other.

 

five7kid, you said the rods where weaker than the 2 bolt main. How much hp/ftlb can a stock 305 handle?