Finally got my car out of panel shop prison and pulled the motor/trans last night . Trying to locate the coolant leak in the motor .

The block is cracked in #4 main from cap up into coolant passage .

I guess from a glass half full view I am lucky , it ran maybe 6-8 passes like this and I didn't drive over the crankshaft .
If only there was a readily available cross bolt iron block , I would buy 1 in a heartbeat ( realistic pricing )
Oh well time to put the new TF270 heads onto my old 440 short and keep going


Tex

Glad you caught it before it got you. Do you guys run engine diapers

No diapers , not fast enough . Be to awkward on a street car .

Tex

Good catch. Could have been a lot worse.

Those dang stock 440 blocks will crack the main webbing once you exceed the design limits on the HP, sorry to hear that
Detonation and main cap walking are the cause usually

Fixed it for you

hahaha
20 months of racing once a month minimum and daily driving .
BAH
darn it , conservative tune and billet caps/studs
back to the drawing board

Tex

I haven't seen or heard of a stock 400 block cracking the main webs yet I know a NHRA S/G racer that broke a bunch of stock 400 main caps before switching to after market main caps, he would run the tune up on the ragged edge also
My old 518 C.I. low deck 400 block stroker pump gas motor had the heck wrung out of it, shifting above 7000 RPM at the track for hundreds of runs and some beating on it on the street with no block problems other than some main cap walking when I had the 906 heads on it
I did have the old Mopar brand ductile iron main caps and ARP main studs installed in it to start with
I now use the 440 Source aluminum main caps and ARP main studs, so far no negative results on any of my customers motors Knock on wood

Yes Cab .
But even if I could get a 400 block here , is major swap all my stuff is RB .
I had 440 Source billet steel caps/ARP studs

Tex

Now you have my 400 crack the main webs after 1250 runs made good power best pass 8.69@156 went throw the traps at 7600 it had the 440 Pro-Gram bullet steel caps Keith Black 9/16 studs 4.150 stroke steel h beam rods might of been OK with the aluminum caps.

I can’t tell you how many 400 girdled blocks we have had break in the Pittsburgh area but we have a lot of good running Mopars in this area. It’s been a lot I’ll tell you that. About everyone I know stepped up to an Indy or Keith Black blocks years ago.

John ,
I accept stepping up , don't need to tempt fate
BUT
a KB wedge will cost give or take A$10000.00 on my doorstep - bare .
I would far prefer an iron block for daily use and my goals , low 10s @ 3700lbs through the exhaust

Tex

Honestly if I was 3700 pounds and only wanted to run low 10’s I would put my car and myself on a diet and build a nice small block. These things can be impressive plus you start out lighter already from the small block.

DIET !

I am barely 150lbs wringing wet .
Not sure my 68 B Body is going much lighter , already has aluminium engine parts , aluminium radiator , light wheels , glass bonnet and front bumper . There is no rear seat / bench front .
And again all I have is big block and there is no new small block blocks either . And no not gen3 .


Tex

Stock 400 block in my ride at 2330# race weight.....I make the sign of the cross every pass lol

Sure seems to me that aftermarket caps and girdles don't do much, if anything, to keep the block from cracking. Seen just as many cracking w/ good caps and/or girdles as I have w/ stock caps.

The solution for not cracking stock blocks is really simple....... make less power.😎

Or let it sit in the shop unused. Make power and use it and both high and low deck blocks will break.

After seeing this, I am really mad at myself for not getting a aftermarket block, sorry this happened to you Tex.

That’s why even though I had my Keith black block the more I thought about it I grabbed a mega block that was offered to me. The way I looked at it was I would sooner or later be building an engine for another car I have sitting here and it costs me about 1100.00 to prep a stock block to build. The mega block was more or less ready to go from another build so it made sence to grab it. It sits in darkness.