Machine 360 crank to fit in a 340 main block

[TXcharger07]

I used the TC 1930 Clevite Pistons, you need to have the Valve reliefs cut in them though any competent machinist can handle this process. The Compression distance is 1.678 so final deck height at 0 with the 3.58 crank will be 9.591 leaving the machinist to square deck it .009 or more if needed. You can clean it up for compression you want with the head gasket. Compression with these and valve reliefs at 5cc ends up right at 10.5:1 with 62 cc heads. I am using the INDY/RHS X heads no port work at all. Comp Cams XE284 Hydraulic Flat Tappet, Gear Drive, Mopar Performance Crank, Eagle SIR ESP 5140 Rods, Line Honed with main studs, Head Studs...Cometic Gaskets Should be put together in 2 weeks from today. I had all the parts laying around including the block. Need to keep busy in my mind. This one is just a hobby motor that I am possibly trading for a 69 Dart GT...

Here is a current link to these pistons. I used .030 over. These ones are .040 over.

http://cgi.ebay.com/ebaymotors/MOPA...r_Truck_Parts_Accessories?hash=item5636ac50d8

Is that in a 318?

what pistons are you going to use?

KB steel pistons, steel rods, I would think stock size would be fine. And it should have a really high rpm and turn it quickly. Should be a pretty bad motor. Might even put a 6-pac on it.. but we'll see how I like tuning when i get to that point

 

[Mad Dart]

318 Block 360 Crank..... You need to be really careful on the Compression Distance or you will be jacked if you try to use the wrong ones. I have already figured this out for the 349 build using the 318 block. Almost perfect deck height using a CHEAP piston!

 

[70aarcuda]

besides the compression height .....

watch out for the crank hitting the skirt of the pistons....

 

[hemijoejr]

I have built 1 of these 3.58 stroke 318s and am working on #2. Both of them were with the now discontinued 3.58 stroke cast crank that mopar offered. The first one I built was with forged .060 over pistons out of a 283 chevy. That equates to a .025 over 318 bore. I had the rod journals cut down and widened to LJ chevy 2.100 size and rehardened the crank (they hold up better when they are rehardened) I also used pressed 6.00" chevy rods. Machined dished into the pistons to get 9.5-1 comp with magnum heads. The underside of the piston also needs to be cut about .040 to clear the crank. That one chassis dynoed very close to 300hp at the rear. The other one I am building is with exactly what you have. .030 over TC 1930 pistons. I cut the block to zero deck. I have valve notches cut into the pistons and am waiting to check the assy. It should work fine!! Check your clearances!!

 

[Mad Dart]

besides the compression height .....

watch out for the crank hitting the skirt of the pistons....

I checked and the MP Crank will clear the skirts with these pistons so far. Have not put in block yet but mock up so far is good on the bench. If you are in a situation where the skirts hit you can shave the counter weights on the crank before balancing.

 

[Mad Dart]

I have built 1 of these 3.58 stroke 318s and am working on #2. Both of them were with the now discontinued 3.58 stroke cast crank that mopar offered. The first one I built was with forged .060 over pistons out of a 283 chevy. That equates to a .025 over 318 bore. I had the rod journals cut down and widened to LJ chevy 2.100 size and rehardened the crank (they hold up better when they are rehardened) I also used pressed 6.00" chevy rods. Machined dished into the pistons to get 9.5-1 comp with magnum heads. The underside of the piston also needs to be cut about .040 to clear the crank. That one chassis dynoed very close to 300hp at the rear. The other one I am building is with exactly what you have. .030 over TC 1930 pistons. I cut the block to zero deck. I have valve notches cut into the pistons and am waiting to check the assy. It should work fine!! Check your clearances!!

Yes clearances need to be checked. Did you have to notch your block for the rods/stroke??

 

[hemijoejr]

With the Chevy stuff, it fit right in. I checked but didn't need any clearancing at all. I havn't checked the all Mopar setup yet. Should be doing it within the next month.

 

[superdart]

I would prefer to go with a 318/340 stroker crank instead of cutting one down.

I stumbled on a NIB Mopar Performance forged 3.55 stroker crank. It's sitting at home just waiting for the day I decide to build a 346. The standard bore 318 block is idle in my shed until I'm ready.