Looooong stroke crank

[Dave]

Have you guys seen the NEW Mopar Perf. catalogue? They have a small block 'heavy duty' cast crank with a 4" stroke!! WOW talk about a jump up from the 360's 3.58" stroke.
With that crank and one of the old (496)casting 360 blocks and a .100 over you would end up with a 420 CU.IN. motor and tell the world its 'just' a 360. Even with a normal .030 over it works out to something like 402cu in
I've heard conflicting opinions on whether that old block can take .100 over but they would all take .080 and that's still lots more than a 360.

[Jesse Lackman]

I have sonic tested many pre 1974 360 blocks that would go 4.100" and still have .150+ cylinder wall thickness. What I wonder is what is the minimum cylinder wall thickness?

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[OldReliable]

A 4.1 bore with a 3.6 stroke is 380cubes.
The 3.6 is made by offset grinding the 360 crank .020". I reduced the 360 mains to the 340 size and used a early 340 block plus .060"
We used to build Hoover motors (Still have one left) that were a 360 engine with modified Low compression 340 pistons but they were hard to balance. Cubes with them were 368 to 371 depending on how far you overbored. I didn't think the 360 would stand a 4.1 bore but maybe it will. Interesting thought thanks for mentioning it.
big-d@sympatico.ca

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Don
94 V10 Ram(001),74 440 Charger,63 Max Wedge

[Christopher]

The old 360's when first released as passenger car engines were made with the 340 cylinders.This is why they will take a +.060 overbore and larger and still have meat left.

[Jesse Lackman]

This spring I built two 360s with 340 HIGH compression pistons for IMCA Modified racing.

One was built with used cast pistons, used piston rings, used Manley Thunderstick hydralic cam, Holley strip Dominator, ported smog cylinder heads. In other words a bunch of used parts we had laying around. The pistons were fit using a Makita side grinder. It was not balanced. This engine made 400hp and 430 ft. lbs on the dyno. The car was geared for 6500 rpm on the straights. It spun the tires so easily that as an experiment to drop off some power it was run in SECOND GEAR for 20+ laps. I wasn't there so I asked what was the rpm? They said we were afraid to look! THis engine went on to run two more months before the head gaskets started leaking. I spent more on fuel for dyno testing it than on the engine itself!

The second engine was built with TRW forged 340 pistons. It had a Hughs HEV-4550 solid lifter cam, new (wow) piston rings, 273 rockers, 12.5-1 compression, ported smog cylinder heads (250+ cfm@28" intake). This engine actually ran on Amoco Ultimate on the dyno. It put out 450hp 430 ft lbs. (J1349 correction). The driver did not like this engine, it had way to much power. It wasn't balanced either. THe pistons ended up weighing about what stock 360 pistons weighed. The IMCA Mod engines can be claimed for $350 so we tried to keep the costs down. This engine is being sold for $1750 carb to pan.

If anyone is interested you can see and hear the 450hp engine on my web site. The 180 degree headers make it sound so neat.

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[This message has been edited by Jesse Lackman (edited February 12, 2000).]

[Dave]

The coolest thing about this crank (to me) is that it is done with production balance!! If this comes true in actual production the only thing left to figure is what pistons to use and what cam. I don't know, but I would suspect that the cam for a long stroke 402 would be significantly differant than one for a "short" stroke 400BB. I could be wrong. (It's happened before )