8 bolt small block crankshaft

-
S

Sb Valiant

Active Member
Joined
Jun 21, 2013
Messages
25
Reaction score
0
Location
West Middlesex
I have a 8 bolt 3.31 stroke crank from 6-17-74 and has the numbers 905 off to the side from the date. Any idea what brand crank? Moldex, Kellog, T/A??? I believe this is a forged crank.
 

Attachments

  • 2013-06-22 23.56.35.jpg
    40.2 KB · Views: 348
hit one of the counter balances with a screw driver handle and see if it rings like a bell
 
agree 318-3 truck crank.....and that is one bad-a$$ crankshaft, luck to find one...
 
How could it be a 318-3 truck crank? Sorry just not familar with it. So if it is they are a good piece I see! How good exactly? Will it handle the throw wt of h beams rods and 7000 rpms?
 
yes they did but only in some "rare offerings" by MOPAR. They were mostly used in industrial apps, farm trucks etc. Look it up in the old MOPAR PERFORMANCE book. (Written by Larry Something [sorry forgot the last name] According to the book they were the ultimate 3.31 crank and good for 9000 rpm's (from what I can remember....I have the book, I should go look at it...)
 
That would be cool if you could look it up omahamoparguy I guess I might have a real nice piece on my hands! If they are good for 9000 then H beam rods and the throw weight wouldn't hurt it like a cast mopar crank. I only plan on 7200-7500 rpm max so I'm in good shape!!!!
 
Actually, I think this may be an old Direct Connection race crank as they were sold over the counter. the 905 casting number was mentioned in the old mopar performance book (BY Larry Schreib and Larry Atherton). The info is kinda vague. All it says is something about the 905 "Good guy" crank and that Petty enterprises was making a copy of the "factory crank" only with a longer stroke. It is indeed a "P" part and is listed in the book as a 340 forged crank with 8 bolt flange.
 
OK here are the numbers:
P3690905 340 Engine Forged 8bolt flange
P3690945 355 Engine Forged 8bolt flange
2843885 318-3 Forged, Hardened Crank, 3.31-inch stroke

It does not say if the truck crank is an 8 bolt or not and I cannot tell by looking at the picture of it so I may have heard that info from somewhere way back in the deep recesses of my brain.....haha. would be interesting to actually find one of those truck cranks. I have a feeling they were in polysphere engines.
 
check to see if the bolt holes are 7/16 thread or 1/2 thread...as the 8 bolt cranks used 1/2 threads. Also check to make sure all the holes are threaded as even the 6 bolt cranks have holes that are not threaded..

I had a 340 main 3.58 stroke billet MP crank with the P number stamped on it....bought it for 300 bucks..sold for 550...

none of the OEM cranks had 8 bolts...
 
I'll try and get some better pics and post them later. I'll also look at the crank again for any more numbers. It would be nice to possibly identify which one it exactly is! Thanks for the info omahamoparguy and others! We got it narrowed down on what it could be!!
 
in the picture of the 318-3 truck crank from the book it show the crank also being solid in the journal throw area (unlike the one you have there).
I'm sure you will be good to go as, according to this book, stock 360 cranks were used in nascar by some people with fine results!!
 
Wasn't able to find out crank bolt size but I got some way better pics
 

Attachments

  • 2013-06-23 14.51.00.jpg
    95.8 KB · Views: 345
Last pic and thanks for all of the info so far everyone! Greatly Appreciated
 

Attachments

  • 2013-06-23 14.52.13.jpg
    93.2 KB · Views: 303
I found some numbers on the crank but are hard to make out. Looks like 253245 then something else could be a p then 14 at the end.
 
how about a picture of the flange with the "8" holes...lol

and are all 8 holes thread?
 
You must log in or register to reply here.
-

Back
Top