Small Block Engine EXPERTS

-
Treblig

Treblig

Well-Known Member
Joined
Oct 5, 2013
Messages
8,464
Reaction score
6,764
Location
South Texas
I got some main caps with a group of parts and don't know what they fit (318 or 360). I want to sell the ones I don't need but first I need to identify. PLease chime in if you know what these fit??

The first 3 pics are one set of caps (no main). The last 5 pics (complete set). I think the complete set is 318 (??) but I have no idea what the first set fits???
thanks,
Treblig
 

Attachments

  • DSC05961.jpg
    47.4 KB · Views: 512
  • DSC05962.jpg
    47.2 KB · Views: 474
  • DSC05963.jpg
    46.1 KB · Views: 447
  • DSC05964.jpg
    33.5 KB · Views: 432
  • DSC05965.jpg
    43.8 KB · Views: 417
  • DSC05966.jpg
    36.8 KB · Views: 418
  • DSC05967.jpg
    37.2 KB · Views: 414
  • DSC05968.jpg
    35.9 KB · Views: 410
Measure the bolt spacing; 360 has greater spread due to larger main journal dia. Don't have any thing handy to measure myself to give you a reference, sorry. Maybe others can give you the dimension.
 
I'll go out and check the bolt hole distance and compare the heights.


Thanks,
Treblig
 
340 main caps are also slightly taller than the 318 caps, although they can be interchanged. If I remember correctly, the 340 caps are about .250 taller than the 318 caps.
 
replicaracer43 said:
340 main caps are also slightly taller than the 318 caps, although they can be interchanged. If I remember correctly, the 340 caps are about .250 taller than the 318 caps.
Click to expand...

Well I went out to do a little checking. The heavier duty caps are taller and the bolt holes are further apart. The bolts that came with the larger caps do screw into the 318 block I have but the bolts seem to be too long. Since the larger caps are taller the bolts are also longer and probably wouldn't work on the 318 block. It looks like the taller caps will fit on the 318 but since the holes are further apart they must not be 340 caps??? So are the larger caps 360?? The larger (taller) caps also have a bigger bearing (larger diameter).

treblig
 
Treblig said:
Well I went out to do a little checking. The heavier duty caps are taller and the bolt holes are further apart. The bolts that came with the larger caps do screw into the 318 block I have but the bolts seem to be too long. Since the larger caps are taller the bolts are also longer and probably wouldn't work on the 318 block. It looks like the taller caps will fit on the 318 but since the holes are further apart they must not be 340 caps??? So are the larger caps 360?? The larger (taller) caps also have a bigger bearing (larger diameter).

treblig
Click to expand...
sounds like 360 caps. 360s have a larger main bearing journal. the 318 and 340 caps have the smaller bearing.
 
The 318/340 diameter is just a tick under 2 3/4" whereas the 360 main bore diameter is 3". Measure across the open of the cap to see what you have.
 
Well the larger caps are very close to 3" across where the bearing sits so I can try and sell them as 360 bearing caps with bolts. I have no idea what they are worth but I figure $25 would get them out of my garage?? However I do need some 318 main cap bolts so maybe someone will make me a trade??

Thanks to all..... Treblig
 
Treblig said:
Well the larger caps are very close to 3" across where the bearing sits so I can try and sell them as 360 bearing caps with bolts. I have no idea what they are worth but I figure $25 would get them out of my garage?? However I do need some 318 main cap bolts so maybe someone will make me a trade??

Thanks to all..... Treblig
Click to expand...


I would recommend using new bolts vs used for the mains. You don't know how many clamp cycles that the used bolts have been through and how stretched that they are. You shouldn't use them more than 5 times, then throw them out and get new ones.

I wouldn't take chances on main, rod, or head bolts...
 
krazykuda said:
I would recommend using new bolts vs used for the mains. You don't know how many clamp cycles that the used bolts have been through and how stretched that they are. You shouldn't use them more than 5 times, then throw them out and get new ones.

I wouldn't take chances on main, rod, or head bolts...
Click to expand...

I really can't argue with your point and since I don't have any 318 main bolts at all I'll just buy new ones. The 360 main bolts have been on the shelf for at least 20 years so they haven't seen much use at all so I'll sell them with the 360 caps.

thanks,
treblig
 
Just a shot in the dark but I'm in the market for a set of 360 main caps and bolts. Thanks.
 
The bolt holes should be 3.7" center. Building a '72 block hoping for a successfull build.
 
Have your machine shop check the line bore when mixing caps from other engines.
 
jimbo said:
The bolt holes should be 3.7" center. Building a '72 block hoping for a successfull build.
Click to expand...
I'll check them later this morning. I'm a machinist so I know how to get a good measurement.

Treblig
 
Treblig said:
I'll check them later this morning. I'm a machinist so I know how to get a good measurement.

Treblig
Click to expand...
Line bore. Already prepared to do one, Not bothering to hit the machine shop until I have main caps. Stay tuned.
 
I measured the distance outside of one hole to outside of the other and got 4.137", then I measured the hole .515". So 1.137 minus .515" equals 3.632" (center to center, more or less). The holes are larger than the bolt and they are not perfect so maybe that's why I can't get 3.7. I do know that the other caps I have are 318 and the holes are closer together by about .100". I don't have the rear main cap, only the 4 caps and bolts shown above in post #1.

Treblig
 
You can also measure center to center by inside of one hole to the outside of the other.
 
toolmanmike said:
You can also measure center to center by inside of one hole to the outside of the other.
Click to expand...


That's true but since the holes are not on dead center with the block holes it still won't give me a much better measurement. Even the shouldered part of the main bolt fits with a few (.008"-.010") of play. The cap centers itself in the block "saddles" and the bolts float in the holes. But I can also check them the other way if "jimbo" wants me to.

Treblig
 
I guess we're both out of luck unless to want to buy them then look for a rear main?? I understand if want to keep looking.

Treblig
 
I can't find anything aftermarket. This is making me crazy. Just stupid sh*t. Cheaper to scrap this block and find another one.
 
You must log in or register to reply here.
-

Back
Top