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how to tell a 4 bolt from a 2

129K views 21 replies 19 participants last post by  TANGO 
#1 ·
hey you guys im about to buy a 78 350 four bolt casting numbers 3970010, and i just want to be sure before I go buy this how to check to make sure its a four bolt..

also how can I tell if it has been cracked or stressed also?

Im buying it for 75.oo and the crank and pistons for another 25..

I just want to know most the warning signs. he said it has a set of junk heads on it so the clynders didnt rust and what not. though he did say that it did blow a head gasket, but theres no stress cracks or anything over heated, they saw the anti freeze and they pulled it, which sounds iffy to me..he also said he had eldelbrok heads a **** and it was fast wich makes me beleive even more that he ran it hot.

so im getting back to the point on warning signs to look for and to make sure its a 4 bolt, cause I already have a 2 bolt 3970010 and dont need another, specially if its broke..

thanks and have a merry baby jesus day.
 
#3 ·
No way to be sure unless you physically confirm it by looking at the mains with your own eyes.

That same 010 block was drilled in both 2 and 4 bolt configurations.

Cracks can be checked by a process called magnafluxing. Most machine shops will do it for not much money. But you have to buy it first, then test it. Buyer beware.
 
#4 ·
A casting number will not disclose if it's two bolt or four bolt. You said it had a pair of junk cylinder heads on it to prevent the cylinders from rusting. Before I bought it I would remove those and take a serious look at the cylinders, especially if it has had a blown head gasket.

Buyer beware is excellent advice
Vince
 
#5 ·
302 Z28 said:
A casting number will not disclose if it's two bolt or four bolt. You said it had a pair of junk cylinder heads on it to prevent the cylinders from rusting. Before I bought it I would remove those and take a serious look at the cylinders, especially if it has had a blown head gasket.

Buyer beware is excellent advice
Vince

myself, i'd see if the guy will let you have 'em maggged before you pay him...
but honestly, for a 100 bucks i'd find a complete 350 someplace....
what are you plans?
do you REALLY need a 4 bolt block?
 
#6 ·
Picture of a 4 bolt main.



Picture of 2 bolt main.



Even with stock 4bolt mains your not safe it you detonate the motor it'll
cause this kind of damage.


So you would be better to get a 2bolt main block and have it splayed for 4 bolt caps like the one in the first picture.

Depends on what your doing with the engine as well. The more power your planning on making the better you'lld need to build the bottom end.
Good luck,
Scott
 
#7 ·
Is this imaginary 350 the same imaginary 302 you claim you have????? Please go bother some other board with your fantasies.
 
#8 ·
Centerline said:
Is this imaginary 350 the same imaginary 302 you claim you have????? Please go bother some other board with your fantasies.

Naw,... It appears that the imaginary 302 is on hold,+ this is a cherry brand new hot rod imaginary 350,.....

I imagine if Nathannoschool was even reading the advice supplied to him, you'd probably get your Wish....

I suggest some Great Reading,....
Click on Nathannoschool's name,+ read some of his Other Bazillion threads....
His post down in the Art forum is a Great Read.... :nono:
 
#9 ·
NaythanOldskool said:
hey you guys im about to buy a 78 350 four bolt casting numbers 3970010, and i just want to be sure before I go buy this how to check to make sure its a four bolt..

also how can I tell if it has been cracked or stressed also?

Im buying it for 75.oo and the crank and pistons for another 25..

I just want to know most the warning signs. he said it has a set of junk heads on it so the clynders didnt rust and what not. though he did say that it did blow a head gasket, but theres no stress cracks or anything over heated, they saw the anti freeze and they pulled it, which sounds iffy to me..he also said he had eldelbrok heads a **** and it was fast wich makes me beleive even more that he ran it hot.

so im getting back to the point on warning signs to look for and to make sure its a 4 bolt, cause I already have a 2 bolt 3970010 and dont need another, specially if its broke..

thanks and have a merry baby jesus day.
Maybe you should post's some more pic's of your art work ? :rolleyes:
 
#10 ·
UR50SLO said:
Picture of a 4 bolt main.



Picture of 2 bolt main.



Even with stock 4bolt mains your not safe it you detonate the motor it'll
cause this kind of damage.


So you would be better to get a 2bolt main block and have it splayed for 4 bolt caps like the one in the first picture.

Depends on what your doing with the engine as well. The more power your planning on making the better you'lld need to build the bottom end.
Good luck,
Scott
DUDE, no offence, but you are comparing apples to oranges. the first pic is a 400 bloc, ( note the 3 freese plug holes) a 350/327s and all other engines have just 2 of those freese plug holes ( like the other engine). if you ever see a block with 3 freeze plugs just buy it for cash, then just run away like a baby---> that's would i would do, but there ARE no more 400 blocks here on the left coast, out here in cal. i have looked for a 400 block for years with no luck. i have crawled under 100s of the most likely cars and trucks at "pick and pull yards" and never seen a 3-freeze plug block. now i just buy the "goodwrench 350 engines" (those are 4 bolt aftermarket engines, they say "goodwrencch 350" on the stamped steel valve covers. i just build them into 383s, the next best thing to a 400 small block is a 383 stroker. later... and merry christmas to all of you... :welcome:
 
#11 ·
DUDE, no offence, but you are comparing apples to oranges.
That was the quickest pictures I could find that shows the visual differences between a 2bolt and 4bolt block... I did not care if it was a 400 or 350-down block.
The 4bolt part looks the same regardless. This isn't my first rodeo. :mwink:

If he was not sure what to look for... now he does.

~Scott
 
#17 ·
ap72 said:
YOu can also buy a used stock 400 block on ebay for $200, then get it shipped for $150, and do the required machine work $700. You'll save about $400 and have a nice weak 400 block instead of one of those silly aftermarket "better" blocks. :mwink:
I have a friend who builds sprint car motors who would disagree. The stock blocks run many races. None of his motors ever came back. He's worked with Sonny Lenord and other big names.

But yes, I do agree with if you're going to spend $1100, spen $1500 and get the new one. There are oil improvements and such too on the new block. In my mind it's "insurance.
 
#18 ·
What kind of engine are you going to build? Do you even need a 4 bolt? If you are going to build mild engine dont worry about 4 bolt. If 4 bolt has blown head gasket and ran hot cracked block or ran blown head gasket long enough that you may have to deck the block. I sold a guy a nice 2 bolt block I had he built it put it in a modified ran it on the local 1/2 mile dirt oval. He ran it 10 night won a couple then motor got claimed. Then he put in 4 bolt that I had sold him....it had same problems your 4 bolt had been blowning head gaskets, been ran hot it blew up first night. Go with 2 bolt will be better base for you project!!!
 
#20 ·
that four bolt pic looks to be a dodge engine to me.......but yeah four bolt mains ...looks like splayed caps too...If the timing cover is off and you can turn the crank out of the way sometimes you can peek in past the front main and get a peek in to the second and see the outer bolt..need a good flashlight too..works for me anyway..
 
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