Destroke? 199 crank in 4L?

[sureshot007]

I know everyone goes the other way, but due to the constraints of the rules for my class, I was curious if anyone knew anything about the ability to swap a 199 crank into a 4L.

[Cheromaniac]

It's possible but the problem is finding suitable pistons. If you use the 4.0 rods, the pistons would need to have a compression height of ~1.828" and finding them off-the-shelf is almost impossible.
You might, however, be able to make the 6.0" connecting rods and 1.935" high pistons from a Chevy 292 I6 work for you:

http://www.summitracing.com/search/Make ... Rank%7cAsc
http://www.summitracing.com/search/Make ... Rank%7cAsc

Deck clearance would end up at just 0.018" and flat top pistons would leave the SCR at ~9.5:1.
Displacement with +0.030" overbore pistons and the 199 crank would be 3533cc (3.5L) or 215.6ci.

[sureshot007]

The max displacement in the class is 3313cc...

[Cheromaniac]

In that case you're going to need a 4.2L block. The cylinder bore in the 4.0L block is 3.875" so even without an overbore, the minimum displacement you're going to get is 3478cc. If you use a 4.2L block and 199 crank, the minimum displacement without a cylinder overbore is 3258cc. If you overbore +0.030" displacement will be 3310cc so that'll be perfect for you.
The question now is which piston/rod combination to use. The 4.2L block has a deck height of ~9.490" so if you use the 4.0L rods (length 6.125") and Sealed Power Z233P30 pistons (height 1.80"), the deck clearance will be 0.065" so you'd need to shave it down. The pins of those pistons are slightly small for the 4.0L rods but you could either have the rod small ends bushed or lightly modify the pistons to accept 0.931" pins.

[sureshot007]

It just blows me away that you guys know all of these specific measurements offhand.

Do you think I'd be able to get the CR into the 11:1 range?

[IH 392]

If you go with the 258 block you might as well stay with the 199/232 ('70 and earlier blocks) as all 199's, 232' and 25's all use the 3.75" bore, the one and limiting factor is the bellhousing, it's unique to these blocks, so it somewhat limits transmissions.
Custom domed pistons will be required to get any compression over about 8:1, the 199's all had flat top pistons to begin with, and the heads had smaller chambers too, I had a 199 head on my 258 in my '68 American before I swapped in a V8.

[sureshot007]

My original idea was to swap the crank into a new block because I figured it would be a lot easier to locate a crank vs a whole engine. It doesn't seem like the 199/232 engines are a dime a dozen, or else I'd just use a 199 in the first place. I thought it would go without saying that it has to be cheap enough to be feasible.

[SIXPAK]

A person could take the 199 crank and have it bored to remedy the trans issue. The 199's have the small pilot but a good machine shop could take care of that. I have a complete 199 (less intake and exhaust manifolds) sitting in the garage. If you need it let me know, I'm in Ohio.

[IH 392]

The trans issue is the bellhousing's not the pilot bearing?, I'd make a pilot bushing long before I whittled on the crank?

[SIXPAK]

IH, In my case you would have to machine a $1000 converter to get it to fit the crank. That is why I would go the crank wittling route.

[jsawduste]

Check with the JeepSpeed folks. They are doing Destrokeing for the class. Then turning around and running 6,000rpm plus with them.

[IH 392]

IH, In my case you would have to machine a $1000 converter to get it to fit the crank. That is why I would go the crank wittling route.

I still don't see the fascination with slush boxes? , the one and only slip"O"matic I own is in my Scout and I have a Warner T-19 sitting in the garage to replace it with!

[CobraMarty]

I would like to destroked to 3.0L and put a supercharger on it.

[sureshot007]

It's already low compression, why bother destroking it?

[SIXPAK]

IH, In my case you would have to machine a $1000 converter to get it to fit the crank. That is why I would go the crank wittling route.

I still don't see the fascination with slush boxes? , the one and only slip"O"matic I own is in my Scout and I have a Warner T-19 sitting in the garage to replace it with!

Trust me, I'm a gear jammer at heart. I used to race a T-15 with transplanted gears from closer ratio Gremlin trans. Then we went to a Liberty prepped Super T-10 and ran three gears in 300 ft. Miss those days!