Big Inch Small Block

[33IMP]

I have done some research on cranks, I've seen Molnar makes one for 4 inch stroke as do a few others its going to be awhile before I do anything with the motor, I have a few people that want to buy the motor as is I guess for the Indy heads and the " R ' block. It all depends on my finances the next few months, it will determine if I sell it or not. My just finished back up 367 bent a valve after 15 runs that problem has to be addressed first.

Ouch.
BEAUTIFUL Dart, by the way!

 

[Bighead440]

To me, unless there is no budget limit, the 422" 340 or 360 stock-block-based engine is the best CID bang for the buck. That's a 4" crank with 4.100" bore. It needs W2/W5 or Trick Flows with 2.05-2.08" intake valves and roller valvetrain to really be worth it, IMO. The extra cubic inches are nice, but the 4" combos have torque aplenty and still rev quite nicely. You need some serious heads to utilize 476", and lots MORE MONEY than even an R-block!

 

[33IMP]

To me, unless there is no budget limit, the 422" 340 or 360 stock-block-based engine is the best CID bang for the buck. That's a 4" crank with 4.100" bore. It needs W2/W5 or Trick Flows with 2.05-2.08" intake valves and roller valvetrain to really be worth it, IMO. The extra cubic inches are nice, but the 4" combos have torque aplenty and still rev quite nicely. You need some serious heads to utilize 476", and lots MORE MONEY than even an R-block!

Agreed! But every mega inch small block Mopar I know of, has some very,VERY serious hi dollar heads on it. There would be no point otherwise. So far, pro ported w8/w9 appear to be the minimum, on the ones I have seen.

 

['68cuda416]

To me, unless there is no budget limit, the 422" 340 or 360 stock-block-based engine is the best CID bang for the buck. That's a 4" crank with 4.100" bore. It needs W2/W5 or Trick Flows with 2.05-2.08" intake valves and roller valvetrain to really be worth it, IMO. The extra cubic inches are nice, but the 4" combos have torque aplenty and still rev quite nicely. You need some serious heads to utilize 476", and lots MORE MONEY than even an R-block!

4.100" bore is not something that many 340/360 blocks will be able to safely handle is the issue with that.......at that point you may as well just pull your pants up and pony up for an R block and be done with it.

 

[BVoelzke]

Ouch.
BEAUTIFUL Dart, by the way!

Thanks! its been an almost 40 year labor of love! ( bought it in 1982) with 7 different small block combos based on a.... 318 ( 12.60s best ...360 head ) 340 ( 10.70s...W2 head, 12 1/2 to 1 comp. 627 lift roller cam ) and (11.30s .."J" head 9 1/2 to 1 comp. 557 lift purple shaft mech. cam) 360 ( 10.40 best ...W2 head 11 1/2 to 1 comp. 590 lift mech. cam) and 408 ( 10.69 best ...R 3 block , Indy head , 9.8 to 1 comp. 600 lift mech. cam ) present is my back up 367 .. 360 Magnum block 40 over ...10 to 1 comp. W2 head , 585 / 594 lift mech.cam went 11.09 so far... picture from 1984 ran 15s with a mostly stock 318

 

[Bighead440]

4.100" bore is not something that many 340/360 blocks will be able to safely handle is the issue with that.......at that point you may as well just pull your pants up and pony up for an R block and be done with it.

Yes, you must sonic check, but many 318s will safely take 4.000" and 340/early 360s will go 4.100" if they pass the test. If you are scared, go 4.030" and live with a 408/416." Aftermarket block is always best, especially for main webbing girth, but at a premium cost/availibility.

 

['68cuda416]

Yes, you must sonic check, but many 318s will safely take 4.000" and 340/early 360s will go 4.100" if they pass the test. If you are scared, go 4.030" and live with a 408/416." Aftermarket block is always best, especially for main webbing girth, but at a premium cost/availibility.

Not a matter of being scared, I already run a .060" 360 block that has held up fine but everything else is aftermarket blocks and yes it comes at a cost but also comes with complete confidence in my blocks holding up too.

 

[justinp61]

Yes, you must sonic check, but many 318s will safely take 4.000" and 340/early 360s will go 4.100" if they pass the test. If you are scared, go 4.030" and live with a 408/416." Aftermarket block is always best, especially for main webbing girth, but at a premium cost/availibility.

Its one thing for a production block to go 4.100, but it’s another for it to survive making good steam.

I’m not going to invest a bunch of money in good heads, machine work and rotating assembly, then take a chance on pi$$ing it all away with a production block failure.

 

[Nat]

If you put it back together, I would recommend a molnar crank, or at least a scat.
Eagle doesn't have a great reputation in my circles, but I guess that is a little late, hunh?
All in all, It could have been a lot worse!

Agree got over 8000 miles on my 426 with molnar crank and rods still runs well plenty of 7000 rpm runs on it . Molnar makes good stuff at least all my **** checked out well and has not broken , yet .