urban legend , truth or trash ?????
 

The legend is: all 350 truck engines were 4-bolt mains. Is this so???

I have seen both but by all means I am not a expert.

I would say NO. I have seen a lot of truck motors that were 2 bolt, nothing wrong with a 2 bolt.

I say no as well. I had a 350 2-bolt in my truck back in the day.

If they were all 4 bolts, engine builders/sellers wouldn't brag about motors being 4 bolts. :D

Definitely NO. Not all 350's are 4 bolt mains. Take a 3970010 for instance, it could be a 2 or 4 bolt main.

4bolts are overrated

Better to have and not need, than to need and not have.

Id sell the 4 bolt for some useful cash to somebody who thinks 4 bolts are better & than use 2 bolt...ive done it before, & will do it again

I have a 4 bolt 4 sale!

My truck 350 is a 2 bolt.

not true.

plenty of trucks had 2-bolt motors....even 3/4 and 1 tons...although those are the truck you would most likely find a 4-bolt in.

2-bolts are good to 500hp anyway (just use MainStuds/quality fasteners)...and if you build a motor that pushing that you should be running a new GMPP block or Dart or something and has provisions for a roller cam

an off topic question, do they make main girdles for chevy motors? I ask because I see them availible from everyone for olds motors, but not for chevies...I'd assume that since you can pretty much fall over a 4 bolt main block, that it's not necessary?

Very interesting!! So a Myth it is seems!! I was also told they used only 4-bolts in the bigger station wagons and Suburbans.
Dave

lots of "theories" on what they put them in and identify them by....i don't think anyone reall knows...maybe not even GM.

they were more popular in heavy trucks, burbs, big station wagons - but not all of them had 4-bolts, and i'm pretty sure alot of the performace years - camaro's etc had some 4-bolts.


as far as the main girdles - i've seen them before but don't know who makes them - you would have to be pushing some serious hp/tq numbers to need one. - most guys just go with a dart/world block if they need that much beef..and you can get them with billet steel splayed main caps :metal: :cool:

I had a 4 bolt 350 in a(original) 69 Camaro SS I once owned.

I heard that all truck V8s were 4 bolt. We know thats not true.
I have two 69 300horse 350s(one is the original motor in my 69 Camaro SS) both are Tonawanda engines, one is a 4 bolt, one is a 2. I'm guessing supply and demand determined if a vechicle got 4 or 2 bolts.

:rolleyes: I'VE BUILT MORE THAN A FEW ENGINES, & MAYBE A 4 BOLT MAIN IS OVERKILL BUT I WOULDN'T CONSIDER BUILDING A TWO BOLT WHEN 4 BOLT BLOCKS ARE SO PLENTIFUL. THEY ARE THE SAME COST FOR THE BLOCK & THE SAME TO REBUILD SO WHY NOT?? . ANYBODY GOT A THEORY ON WHY 2 BOLT BLOCKS ARE SO MUCH STRONGER & BETTER THAN 4 BOLT BLOCKS.??

(QUOTE) most guys just go with a dart/world block if they need that much beef..and you can get them with billet steel splayed main caps (QUOTE)

EXCEPT THE COST OF THEM MAKES IT IMPOSSIBLE FOR ME. FOR THE COST OF A DART BLOCK WITH SPLAYED CAPS, I CAN BUILD A COMPLETE 4 BOLT 350 FROM CARB TO PAN. :rolleyes: :rolleyes: JOHN

as far as same cost, I geuss that depends. here I can get 2 bolt 350s for little or nothin...but guys are gettin 250.00+ for 4 bolt bare blocks...so depending on what its usage was, Id rather spend the 250.00 elsewhere. Ive never busted a 2 bolt in all my years, however ,I do believe 4 bolts are crucial in heavy towing applications

:rolleyes: OUT HERE IN NV. YOU CAN GET A BARE 350 BLOCK FOR $50 -$75 AT MOST ANY JUNKYARD , & IT DOESN'T MATTER IF IT'S A 2 OR 4 BOLT BLOCK. FOR $250 + YOU CAN GET A COMPLETE RUNNING ENGINE. :rolleyes: :rolleyes: JOHN

I asked a buddy about this who owns a machine shop and has built many 350s from stock to built. His opinion is a 4 bolt block is good for hi horse/ torque applications. He also said about 9 out of 10 stock 4 bolts will have at least one main bolt that is not even close to torque specs. (usually 2 will be loose).
And to answer the main question, trucks came with 2 or 4 bolt mains.

I've got a #010 350 that came from Tonawanda.....

....and I've been waiting to pull the pan this spring to see if it's a 2-bolt or a 4-bolt. :)

It gets better!!! I pulled the engine ( owner said it was original and tag on truck has an option listed for the 350 c.i.) I started checking numbers for 2 or 4 bolt and the block numbers say 400 c.i. and the head has 350 numbers!!!!
Still need to pull apart to find out for sure.

wolfthing, thats the only true way to know.
there is nothing wrong with a 2 bolt. around here they are using them in street stocks for the dirt circle. some guys are even running upwards of 600 HP on them.
truth be told the main caps is not the weak point. all the extra bolts do is HELP keep the main bearing journal round under SEVERE low RPM torque load or idiot drivers side stepping the clutch.

Its always been a debate and always will be..Does anyone personally know anyone who has had a problem with strength after building a 2 bolt motor?