Disaster...360 Engine blew a connecting rod

[chargerdon]

   Tragedy struck on May 30'th...

Took my 74 Challenger with 360 to the local track on test and tune day.   Its an 1/8 mile track and my best pass out of three was an 9.258 74.5 MPH.   This would equate to a 14.43 1/4 mile.   Track conditions were poor...it was unprepped so traction wasn't great and the temperature was 88 with 65% humidity.   Track itself (Galot in Dunn NC) is at 400 ft above sea level, so this would equate to around 2140 ft altitude and that correction .974 would have given me a 13.9..   Not bad.   

However, on the drive home...  a connecting rod gave loose and put a big hole in the block, ruined the crank, two rods and pistons !   Ouch DAM

I didn't have the engine built originally...  But after disassembly and showing rods to the new engine builder, he did a part number cross reference and found the connecting rods to be "oem" qequivalent Cast I beam rods.  They believe they just weren't strong enough and that a snapped ARP bolt may have been over torqued as well.   

The good news is that my Heads ( 915 casting J heads with 2.02 Intake valves, cut so that CC at 65) are not damaged other than two valves need replaced.  New Lunati Cam, springs, hydraulic lifters all good as is the Edlebrock Intake manifold and the Patriot long tube headers.   Also, will need new oil pan and timing chain cover.  All cracked or with holes.   

So, I need a new short block.   Looking on line on Ebay and other searches found several "crate engines" 360 strockers to 408 mostly all in the $2500-$3800 price range.   But, based on threads here and reading the "reviews" more horror stories than successful.   So, very leary of engine builders doing a crate short block.   I decided to look for a salvage yard 360 core (i live near Raleigh, NC) but none of the salvage yards around here had any.   Found one in Winston-Salem, NC...  It was listed as "good running engine when pulled from wrecked 72 Plymouth".   They started out wanting $600 but when i explained i was only looking for a good 360 La core, they came down to $200.  Ok...  So, made the trip to get it, only to find it had sat out in the open for who knows how long.   I put a wrench on the crank pulley and it was fully seized !   I was allowed to strip it and remove a head, and i found it full of water !...   Maybe still rebuild-able and maybe not.    I showed displeasure at being told it was a running engine..  and negotiated a price of $100 and at that i was taking a chance..but..at worst there is my replacement timing chain cover and oil pan.   

Took it straight to a local engine/machine shop to see what they thought of it.   "ive seen worse they said" but wont know until its stripped and put into the block boring machine.   My plan is to have it cleaned, checked, bored to .030, new cam bearings and all new frost plugs.   Then put in a stroker kit.   It took me two afternoons to strip the engine..had to pound out the pistons.  Then took stripped block to the engine machinist.  Im still waiting on the shop to say yea or ney..   Im very hopeful. 

Machine shop is going to help and purchase all of the parts individually (to get a better price) but it basically will be the same as a SCAT 1-98113BI rotating assembly.   It will have new Icon Forged pistons, SCAT forged Iron crank, Scat forged 4340 connecting rods, new rings, and bearings.   For all of the parts and including resurfacing the heads, and putting in 2 new valve guides and stems and a new intake and exhaust valves total comes to with tax $2026.   Not so horrible. 

So ill end up with a new 408 stroker engine. 

Will keep everyone posted..   And welcome any suggestions..   

[RUNCHARGER]

Sounds like you are on the right path. A few positives I see; Choosing a forged stroker crank, 72 block which should have fairly thick cylinder walls. Hopefully the block does not have freeze cracks from having water sit in it.

[ledphoot]

That's not bad at all. In the end you will like the extra 40 cubes you get with the Stroker crank. Make sure they go through your heads so they can get air in and out of the engine. Also note you can run a cam with a little more duration and maintain street manners. Even with a mild cam and heads you should be in the low 13 / high 12 second club.

[Brads70]

Sorry to hear this. Crappy luck but building a replacement  at least you will know whats inside.

[1 Wild R/T]

Just a thought... I'd be looking for a 89-93 360 roller block...   Roller cam for a fraction of the typical cost...

[ledphoot]

Just a thought... I'd be looking for a 89-93 360 roller block...   Roller cam for a fraction of the typical cost...

Good point on the roller... I'd love to have a roller cam in my build!

[RUNCHARGER]

That would be a step up alright. Factory engineered, roller lifter setup just works especially for a mild streeter.

[Chryco Psycho]

He was looking for a roller block , just nothing around there at all , Maybe Petty used everything up 

[chargerdon]

Good News...Engine/machine shop called and let me know that they bored the worst two looking cylinders (.030) and that they look ok !   So good block.   

Interesting...his prices for the rotating assembly separately as individual parts came out to be around $40 more expensive than buying the "kit" from Jegs which had the best price thanks to a $100 discount on parts exceeding $1,000.   $1408 to be exact.   So, my engine builder will cost about $40 more at around $1445.   However, modern economics...wife has a credit card that this month (June has a "buy local" promotion going on..) they are giving 10% cash back on any purchase from local retailer of over $500.    This means that by having my engine builder buy the parts (and im sure he gets a discount) then i can get close about $202 back on the total purchase including his labor !   Guess what its crazy, but, i'm having him buy the parts and then use the credit card on the entire $2026 bill with them !! 

[dodj]

Sux what you are going through, but glad you are getting a break..

[RUNCHARGER]

It's nice your local builder will benefit from selling you the parts. I'd sooner a little guy make a profit than Summit or Jegs make one. Mind you it will probably come from there anyway.

[Chryco Psycho]

Timing is everything , I am glad you are able to move forward on this at least 

[Flatdad]

I thought mopar factory I-beams were forged? Did somebody replace stock forged rods with cast rods? Are stock 360 rods cast??

[RUNCHARGER]

Mopar rods were forged.

[Chryco Psycho]

I don't recall any Mopar engine using cast rods but there were lighter duty rods .
I maintain someone did something wrong machining or building  it